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1. i5 ik 10k E 100k requency Hz 940865e Fig 3 12 Pressurefidd correction for the microphone Response dB 54 100 1k 10k 100 k Frequency Hz 940869e Fig 3 13 Typical pressure field response for the microphone BE 1375 12 Falcon Range of Microphone Products 3 13 Microphone Handbook Chapter 3 Prepolarized Free field Ap Microphone Type 4189 Directional Characteristics 3 4 Directional Characteristics Typical directional characteristics are given in Fig 3 14 and Fig 3 15 The character istics are normalised relative to the 0 response Ti ATE AUT WI HEEL LETT mRNA ULL 5 101 I 2038 i 06 TLL VIN mE d HAT A M WAN Jl Ill 5 o M Il MUI HHN WW MA ai A UA n S arg HTT NGA MTM VV NLA li WIR Am any UL NIIE Jil QUUM 31 5 kHz J Ill 6 3 kHz 27 8 kHz 20 kHz Wor 10 kHz 9 KA os 12 5 kHz ies tre zx I N I UM Hill MUI 1802 940786e Fig 3 14 Typical directional characteristics of the microphone with Protection Grid DB 3420 Falcon Range of Microphone Products Bruel amp Kj r Microphone Handbook
2. 500 1k 10k Frequency Hz 50k 9405966 Fig 4 24 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 4 4 4 24 Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 4 Free field 1 5 Microphone Type 4190 Effect of Ambient Pressure The effect of temperature on the free field response see Fig 4 25 of the microphone is the sum of the following effects e the calculated effect of the change in the speed of sound due to temperature on the 0 incidence free field correction e the measured change in the actuator response due to temperature see Fig 4 23 Response dB 1 5 0 5 10 C 0 0 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940808 1e Fig 4 25 Typical variation in 0 incidence free fid d response nor malized at 250Hz as a function of temperature rdative to the response at 20 C see Fig 4 7 over the temperature range defined by IEC 651 4 12 Effect of Ambient Pressure The microphones sensitivity and frequency response are affected by variations in the ambient pressure This is due to changes in air stiffness in the cavity
3. 10 100 Ambient Pressure kPa 1000 940759e Fig 4 28 Typical variation in sensitivity at 250Hz from that at 101 3kPa as a function of ambient pressure 4 13 Effect of Humidity Due to the microphone s high leakage resistance humidity has in general no effect on the microphone s sensitivity or frequency response The microphone has been tested according to IEC 68 2 3 and the effects of humidty on the sensitivity at 250Hz and the frequency response have been found to be less than O 1dB at up to 95 RH non condensing and 40 C 4 14 Effect of Vibration The effect of vibration is determined mainly by the mass of the diaphragm and is at its maximum for vibrations applied normal to the diaphragm A vibration signal of 1m s RMS normal to the diaphragm typically produces an equivalent Sound Pres sure Level of 62 5dB for a microphone fitted with Protection Grid DB 3420 4 15 Effect of a Magnetic Field The effect of a magnetic field is determined by the vector field strength and is normally at its maximum when the field direction is normal to the diaphragm A magnetic field strength of 80A m at 50Hz the test level recommended by IEC and ANSI normal to the diaphragm produces a typical equivalent Sound Pressure Lev el of 4dB Higher frequency components in the microphone output become domi nant at field strengths greater than 500 to 1000 A m
4. 15 12 5 10 0 7 5 30 5 60 25 mpm 1 Random 0 ES 90 180 150 2 5 120 I i j 7 5 10 500 1k 10k Frequency Hz 50k 940805 1e Fig 2 8 Freefied correction curves for the microphone without protection grid Response dB 5 100 1k 10k 100 k Frequency Hz 940935e Fig 2 9 Typical freefidd response 0 incidence for the microphone without protection grid 2 10 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 2 Prepolarized Free field 1p Microphone Type 4188 Frequency Response Correction dB 15 12 5 0 10 30 7 5 1809 Y 60 Random 2 5 2 5 150 X 7 4 TKS 7 5 10 500 1k 10k Frequency Hz 50k 940796 1e Fig 2 10 Freefidd correction curves for the microphone with Ran dom Incidence Corrector DZ 9566 Response dB 5 dB 0
5. 100 1k 10k 100 k Frequency Hz 940885 1e Fig 2 13 Typical random incidence response for the microphone without protection grid 2 12 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 2 Prepolarized Free field 1p Microphone Type 4188 Directional Characteristics Response dB 5 dB 100 1k 10k 100 k Frequency Hz 940883 1e Fig 2 14 Typical random incidence response for the microphone with Random Incidence Corrector DZ 9566 2 4 Directional Characteristics Typical directional characteristics are given in Fig 2 15 to Fig 2 17 The characteris tics are normalised relative to the 0 response BE 1374 12 Falcon Range of Microphone Products 2 13 Microphone Handbook Chapter 2 Prepolarized Free field ip Microphone Type 4188 Directional Characteristics Note The non symmetrical responses are at frequencies outside the microphone s nominal operating range 16 and 20 kHz HITI lil IIl Ill MAU TINTE WEAN WM Il M o iO teu 2 5 n HHA AT AA M Mtf ITE lj N IM Il ll Hl HHH HUN MIN Wu dn mg ITI TIT 0 15 G iiy Mu 2018 25
6. 2 5 10 20 50 100 200 10k 20k See the microphone handbook for further information Frequency Hz Fig 4 2 Microphone calibration chart Open circuit Sensitivity The stated open circuit sensitivity is valid at the reference frequency 251 2 Hz for free field random incidence and pressure field conditions The stated uncertainty is the U gs value the value valid for 95 confidence level Ambient Conditions The ambient conditions are measured continuously during calibration at the factory The calibration results obtained at the measured Environmental Calibration Condi tions are corrected to the reference ambient conditions stated under Valid At 23 C 101 325 kPa and 5096 RH Frequency Responses Two individual frequency responses are shown on the calibration chart Both are normalized to OdB at the reference frequency 251 2 Hz The upper curve on the calibration chart is the individual microphone s open circuit 0 incidence free field response This response is the optimized response for Free field 1 2 Microphone Type 4190 The exact reference frequency is 102 Hz re ISO 266 BE 1376 12 Falcon Range of Microphone Products 4 3 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Introduction The lower curve on the calibration chart is the individual microphone s electrostatic actuator response meas
7. 500 1k 10k Frequency Hz 50k 9406006 Fig 7 25 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 7 4 BE 1379 12 Falcon Range of Microphone Products 7 27 Microphone Handbook Chapter 7 Low frequency Pressure field in Microphone T ype 4193 Effect of Ambient Pressure The effect of temperature on the free field response see Fig 7 26 of the microphone is the sum of the following effects e the calculated effect of the change in the speed of sound due to temperature on the 0 incidence free field correction e the measured change in the actuator response due to temperature see Fig 7 24 Response dB 1 5 10 C 0 5 0 0 0 5 50 C 1 5 500 Hz 1k 10k Frequency Hz 50k 940810 1e Fig 7 26 Typical variation in 0 incidence free fid d response with Protection Grid DB 3421 normalized at 250Hz as a function of temperature relative to the response at 20 C see Fig 7 7 over the temperature range defined by IEC 651 7 12 Effect of Ambient Pressure The microphone s sensitivity and frequency response are affected by variations in the ambient pressure This is due to changes in air stiffness in the cavity behind th
8. 180 100 1k 10k F 100 k requenc E y Hz 940669e Fig 3 5 Typical actuator response phase measured with Electrostatic Actuator UA 0033 This microphone is polarized by a fixed charge carrying layer deposited on the back plate This layer is negatively charged which at low frequencies results in a posi tively increasing output voltage for a positively increasing incident sound pressure 3 3 4 Low frequency Response The low frequency response see Fig 3 3 is the typical response with the vent ex posed to the sound field If the vent is not exposed to the sound field the sensitivity 3 8 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 3 Prepolarized Free field v Microphone Type 4189 Frequency Response increases from OdB at the reference frequency 251 2 Hz to approximately 0 3dB at 1Hz For applications where the vent is not exposed to the sound field take care to ensure proper static pressure equalization to prevent static displacement of the diaphragm The microphone s low frequency response is common for all types of sound field The microphone s lower limiting frequency 3dB is between 2 and 4Hz with the vent exposed to the sound field This is measured during production to ensure that specifications are fulfilled 3 3 5 Freefield Response The microphone s free field correction curves are shown in Fig 3 6
9. j i RR 1k 10k 100k Frequency Hz 940894e Fig 2 3 Typical freefidd response of the microphone with Protection Grid DD 0525 and the micro phones specified tolerances The low frequency response is valid when the vent is exposed to the sound fidd Prepolarized Freefield 1 2 Microphone Type 4188 meets the requirements of IEC 651 Type 1 and ANSI S1 4 1983 Type 1 2 3 3 Actuator Response The microphone s frequency response is determined by adding corrections for the type of sound field to its actuator response obtained using Electrostatic Actuator 2 6 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 2 Prepolarized Free field T Microphone Type 4188 Frequency Response UA 0033 This is a reproducible and practical method for calibrating a microphone s frequency response Response dB 5 20 100 1k 10k 100 k Frequency Hz EA Fig 2 4 Typical actuator response measured with Electrostatic Actuator UA 0033 Response Degrees 0 135 180 100 1k 10k 100 k Frequency Hz 940667e Fig 2 5 Typical actuator phase response measured with Electrostatic Actuator UA 00
10. T m 1k 10k 100 k Frequency Hz 940863 1e Fig 6 3 Typical pressurefidd response of the microphone with Protection Grid DB 3421 and the microphone s specified tolerances The low frequency response is valid when the vent is ex posed to the sound fidd The frequency response of Pressure field 1 2 Microphone Type 4192 meets the re quirements of ANSI S1 4 1983 Type 1 and ANSI S1 12 Type M 6 3 3 Actuator Response The microphone s frequency response is determined by adding corrections for the type of sound field to its actuator response obtained using Electrostatic Actuator UA 0033 This is a reproducible and practical method for calibrating a microphone s frequency response BE 1378 12 Falcon Range of Microphone Products 6 7 Microphone Handbook Chapter 6 Pressure field ty Microphone Type 4192 Frequency Response Response dB 5 20 100 1k 10k 100 k Frequency Hz 940674 1e Fig 6 4 Typical actuator response measured with Electrostatic Actuator UA 0033 Response Degrees 0 135 180 100 1k 10k F T 100k requenc MBRIEy Hz 940675 1e Fig 6 5 Typical actuator phase response measured with Electros
11. 100 1k 10k 100 k Frequency Hz 940933e Fig 2 11 Typical freefidd response 0 incidence for the microphone with Random Incidence Cor rector DZ 9566 BE 1374 12 Falcon Range of Microphone Products 2 11 Microphone Handbook Chapter 2 Prepolarized Freefield Ap Microphone Type 4188 Frequency Response 2 3 6 Random incidence Response A microphone s response in a diffuse sound field is equivalent to its random inci dence response The microphone s random inci dence correction curves are shown in Fig 2 6 Fig 2 8 and Fig 2 10 These corrections are added to the microphone s actu ator response obtained using Electrostatic Actuator UA 0033 in order to determine the random incidence response The typical random incidence with and without the protection grid and with Random Incidence Corrector DZ9566 are shown in Fig 2 12 Fig 2 13 and Fig 2 14 respectively The random incidence corrections are calculated from the free field corrections measured in 5 steps according to Draft IEC 1183 1993 Response dB 5 dB 100 1k 10k 100 k Frequency Hz 940934 1e Fig 2 12 Typical random incidence response for the microphone with Protection Grid DD 0525 Response dB 5 dB
12. 100 1k Hz 10k 100k Frequency Hz 940599e Fig 3 19 Variation of capacitance with frequency Typical capacitance at 250Hz 14 pF The capacitance is individually calibrated and stated on the calibration chart 3 8 Polarization Voltage The polarization charge of Prepolarized Freefield 1 2 Microphone Type 4189 is negative Therefore the output voltage is positive for a positive pressure applied to the diaphragm At the factory the microphone is polarized with a permanent charge Therefore do not apply an external voltage to the microphone In order to ensure the correct polarization during use the centre terminal of the microphone must be kept at the same DC potential as the housing Therefore connect the preamplifier pin normally used for the polarization voltage supply to ground potential OV It is not sufficient to leave it open circuit Falcon Range of Microphone Products Bruel amp Kj r Microphone Handbook Chapter 3 Prepolarized Free field p Microphone Type 4189 Leakage Resistance Accidentally connecting the microphone to a 200V external polarization will not damage the microphone However the sensitivity will fall by at least 8dB and the frequency response will change by 1 or 2dB We do not recommend use in this way Warning Static electricity can destroy the microphone s built in ch
13. 500 1k 10k Frequency Hz 50k 940798 1e Fig 7 6 Freefidd correction curves for the microphone with Pro tection Grid DB 3421 Response dB 15 100 1k 10k 100 k Frequency Hz 940892 1e Fig 7 7 Typical free field response 0 incidence for the microphone with Protection Grid DB 3421 BE 1379 12 Falcon Range of Microphone Products 7 11 Microphone Handbook Chapter 7 Low frequency Pressure field u Microphone T ype 4193 Frequency Response 15 dB 12 5 10 0 7 5 30 5 2 5 eee o 60 7 Random 0 150 120 90 2 5 180 7 5 10 500 1k 10k Frequency Hz 50k 940797 1e Fig 7 8 Freefied correction curves for the microphone without protection grid Response dB 15 100 1k 10k 100 k Frequency Hz 940893 1e Fig 7 9 Typical free field response 0 incidence for the microphone without protection grid 7 12 Falcon Range of Microphone Products Br
14. 500 1k 10k Frequency Hz 50k 940800 1e Fig 5 6 Freefidd correction curves for the microphone with Pro tection Grid DB 3421 Falcon Range of Microphone Products 5 9 Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Frequency Response Response dB 5 20 100 1k 10k 100 k Frequency Hz 940890e Fig 5 7 Typical free field response 0 incidence for the microphone with Protection Grid DB 3421 Correction dB 15 7 5 0 30 2 5 0 150 120 25 90 Ran dom 180 7 ail j 60 75 500 1k 10k Frequency Hz Fig 5 8 Freefied correction curves for the microphone protection grid 50k 940799 1e without 5 10 Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 5 Free field v Microphone Type 4191 Frequency Response Response dB 5 P m 10k
15. 100 1k 10k 100 k Frequency Hz 940872 1e Fig 6 13 Typical pressure field response for the microphone 6 4 Directional Characteristics Typical directional characteristics are given in Fig 6 14 and Fig 6 15 The character istics are normalised relative to the 0 response Hk NIIT WA MU WO 3 NINI TS A P l in Lr EDITI mag Wl WM 1 20 25802 H jS iN ri DUAL f N T M LUI J TUI T MI ui Ul m NNUS 1 ll il i UII M 6 3 kHz 8 kHz 10 kHz B 940852 1e Fig 6 14 Typical directional characteristics of the microphone with Protection Grid DB 3421 BE 1378 12 Falcon Range of Microphone Products 6 13 Microphone Handbook Chapter 6 Pressure field Lp Microphone Type 4192 Dynamic Range MITES A 1 il Ji iij ll I HTH tll Hull NUMINI em Gl BOUM AN NUNS TTA AI TIUS MA ll TH T MI TERRE tH Wn Wo M DAMM TUI Y TIT mu mas oid ul M d ud Hai 2705 i RUM A ll AUN I MINI III Mil 6 3 kHz KOO 8 kHz SS 10 kHz 25 kHz 20 kHz 9 ag as i joa HALT PO ME e TITTY 940853 1e Fig 6 15 Typical directional characteristics of the microphone without protection grid 65 Dynamic Range Definition The dynamic range is the range between the upper limit determined by distortion and the inherent noise floo
16. 10 100 Ambient Pressure kPa 1000 9407616 Fig 7 29 Typical variation in sensitivity at 250Hz from that at 101 3kPa as a function of ambient pressure 7 13 Effect of Humidity Due to the microphone s high leakage resistance humidity has in general no effect on the microphone s sensitivity or frequency response The microphone has been tested according to IEC 68 2 3 and the effects of humidty on the sensitivity at 250Hz and the frequency response have been found to be less than O 1dB at up to 95 RH non condensing and 40 C 7 14 Effect of Vibration The effect of vibration is determined mainly by the mass of the diaphragm and is at its maximum for vibrations applied normal to the diaphragm A vibration signal of 1m s RMS normal to the diaphragm typically produces an equivalent Sound Pres sure Level of 65 5dB for a microphone fitted with Protection Grid DB 3421 7 15 Effect of Magnetic Field The effect of a magnetic field is determined by the vector field strength and is normally at its maximum when the field direction is normal to the diaphragm A magnetic field strength of 80A m at 50Hz the test level recommended by IEC and ANSI normal to the diaphragm produces a typical equivalent Sound Pressure Lev el of 16dB Higher frequency components in the microphone output become domi nant at field strengths greater than 500 to 1000 A m Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook C
17. JU x 100 1 kPa 25 C 35 RH g Procedure 704217 Date 21 Apr 1994 Signature Ko 26 So Example Ko 26 38 12 dB BC 0226 12 2 5 10 20 10k 20k 40k See the microphone handbook for further information Frequency Hz Fig 5 2 Microphone calibration chart Open circuit Sensitivity The stated open circuit sensitivity is valid at the reference frequency 251 2 Hz for free field random incidence and pressure field conditions The stated uncertainty is the U gs value the value valid for 95 confidence level Ambient Conditions The ambient conditions are measured continuously during calibration at the factory The calibration results obtained at the measured Environmental Calibration Condi tions are corrected to the reference ambient conditions stated under Valid At 23 C 101 325 kPa and 5096 RH Frequency Responses Two frequency responses are shown on the calibration chart Both are normalized to OdB at the reference frequency 251 2 Hz The upper curve on the calibration chart is the individual microphone s open circuit 0 incidence free field response This response is the optimized response for Free field 1 2 Microphone Type 4191 The exact reference frequency is 102 Hz re ISO 266 BE1377 12 Falcon Ra
18. 1 5 500 Hz 1k 10k Frequency Hz 50k 9407756 Fig 5 23 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 5 4 over the temperature range defined by IEC 651 Response dB 500 1k 10k Frequency Hz 50k 940598e Fig 5 24 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 5 4 5 24 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 5 Free field Tor Microphone Type 4191 Effect of Ambient Pressure The effect of temperature on the free field response see Fig 5 25 of the microphone is the sum of the following effects e the calculated effect of the change in the speed of sound due to temperature on the 0 incidence free field correction e the measured change in the actuator response due to temperature see Fig 5 23 Response dB 1 5 0 5 10 C 0 0 50 C 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940809 1e Fig 5 25 Typical variation in 0 incidence freefidd response with Protection Grid DB 3421 normalized at 250Hz as a function of
19. 0 0 0 5 50 C 1 5 500 Hz 1k 10k Frequency Hz 50k 940810 1e Fig 6 25 Typical variation in 0 incidence free fid d response with Protection Grid DB 3421 normalized at 250Hz as a function of temperature relative to the response at 20 C see Fig 6 7 over the temperature range defined by IEC651 6 12 Effect of Ambient Pressure The microphones sensitivity and frequency response are affected by variations in the ambient pressure This is due to changes in air stiffness in the cavity behind the diaphragm and changes in air mass in the small gap between the diaphragm and the back plate The effects are shown in Fig 6 26 to Fig 6 28 BE1378 12 Falcon Range of Microphone Products 6 25 Microphone Handbook Chapter 6 Pressure field Lp Microphone Type 4192 Effect of Ambient Pressure The typical pressure coefficient at 250Hz for Pressure field 1 2 Microphone Type 4192 is 0 005 dB kPa Correction dB 3 40kPa change 2 20kPa 1 change 4 10kPa s change Tt D ad 0 oS SS ti 1 500 1k 10k Frequency Hz 50k 940765e Fig 6 26 Typical variation in frequency response normalized at 250 Hz from that at 101 3kPa as a function of chan
20. Pressure field ty Microphone Type 4192 Frequency Response Response dB 5 dB 100 k 940943 1e Frequency Hz Fig 6 11 Typical random incidence response for the microphone without protection grid 6 3 7 Pressure field Response The microphone s pressure field correction curve is shown in Fig 6 12 This correc tion is added to the microphone s actuator response obtained using Electrostatic Actuator UA 0033 in order to determine the pressure field response The typical pressure field response is shown in Fig 6 13 In practice the pressure field response is often regarded as being equal to the actuator response as the difference between them is small compared to the uncer tainty related to many types of measurement Correction dB 4 100 1k 10k 100 k Frequency Hz 9408686 Fig 6 12 Pressurefield correction for the microphone 6 12 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 6 Pressure field lp Microphone Type 4192 Directional Characteristics Response dB 5
21. The microphone s frequency response is determined by adding corrections for the type of sound field to its actuator response obtained using Electrostatic Actuator UA 0033 This is a reproducible and practical method for calibrating a microphone s frequency response Response dB 5 20 100 1k 10k 100k Frequency Hz 940674 1e Fig 7 4 Typical actuator response measured with Electrostatic Actuator UA 0033 Response Degrees 0 135 180 100 1k 10k 100 k Frequency Hz 940675 1e Fig 7 5 Typical actuator phase response measured with Electrostatic Actuator UA 0033 If the polarization voltage is positive as it is with Bruel amp Kj r instruments the output voltage is negative for a positive pressure applied to the diaphragm BE 1379 12 Falcon Range of Microphone Products 7 9 Microphone Handbook Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Frequency Response 7 3 4 Low frequency Response The low frequency response see Fig 7 3 is the typical response with the vent ex posed to the sound field If the vent is not exposed to the sound field the sensitivity increases from OdB at the reference frequency 251 2 Hz to approximately
22. Chapter 3 Prepolarized Free field T Microphone Type 4189 Dynamic Range 1 l I N i HUI M BUT NA I Ww Tr mom AY JUN ALII IN ay AA 3 amt Weite Orin 8 20 aoc Oc lull Vm AIME EM S NG A F 20E m20 0c ar ir QAM NW NU i TIT MU TIT I M AN MU li WW HM NN ULL 31 5 kHz j 55 kHz I Ji lll Iii 20 kHz 940783e Fig 3 15 Typical directional characteristics of the microphone without protection grid 3 5 Dynamic Range Definition The dynamic range is the range between the upper limit determined by distortion and the inherent noise floor Both limits are influenced by the preamplifier This section gives values for the microphone with and without a preamplifier Inherent Noise The microphone s inherent noise is due to thermal movements of the diaphragm These vary proportionally with the square root of the absolute temperature in K The inherent noise increases with increasing temperature With reference to 20 C the inherent noise changes by 0 5dB at 55 C and by 0 5dB at 12 C The maximum variation of this noise for different samples of Prepolarized Free field 1 2 Microphone Type 4189 is 1dB BE 1375 12 Falcon Range of Microphone Products 3 15 Microphone Handbook Chapter 3 Prepolarized Free field Ap Microphone Type 4189 Dynamic Range The preamplifier s effect on the inherent noise of the combined microphone and preamplifier depends on the sensitivity and capacitan
23. Free field 1 5 Microphone Type 4190 Frequency Response Response dB 5 1k 10k Frequency Hz 100k 940888e Fig 4 7 Typical free field response 0 incidence for the microphone with Protection Grid DB 3420 Correction dB 15 12 5 10 0 7 5 30 5 2 5 M U mJ 60 0 1505 Random 120 90 2 5 X 180 TS 500 Fig 4 8 1k 10k Frequency Hz 50k 940801 1e Free fidd correction curves for the microphone without protection grid Falcon Range of Microphone Products Microphone Handbook Bruel amp Kj r Chapter 4 Free field 1 5 Microphone Type 4190 Frequency Response Response dB 5 E T 10k F 100 k requency Hz 940889e Fig 4 9 Typical freefidd response 0 incidence for the microphone without protection grid 4 3 06 Random incidence Response A microphone s response in a diffuse sound field is equivalent to its random inci dence response The microphone s random incidence correct
24. K 26 Sc 2 2 Kg 26 Sg 2 3 Example Correction factor for typical microphone with 1 2 Microphone Preamplifier Type 2669 K 26 30 1 4 1 dB Open circuit correction factor for typical microphone with 1 2 Microphone Preampli fier Type 2669 Ko 26 29 8 3 8 dB 2 3 Frequency Response 2 3 1 General In acoustic measurements there are three types of sound field e Free field e Pressure field e Diffuse field The microphone is optimized to have a flat frequency response in one of these sound fields This response is called the optimized response A microphone s re sponse in a diffuse field is equivalent to its random incidence response BE 1374 12 Falcon Range of Microphone Products 2 5 Microphone Handbook Chapter 2 Prepolarized Free field Ap Microphone Type 4188 Frequency Response This section shows the microphone s typical free field and random incidence re sponses together with the microphone s typical actuator response obtained using Electrostatic Actuator UA 0033 The low frequency response described in section 2 3 4 is common for all types of response All frequency responses and correction curves are shown with a frequency resolu tion of 1 12 octave 2 3 2 Optimized Response 0 incidence Free field Response Response dB 5 dB Tol Tol Tol Tol
25. Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 6 Pressure field 1p Microphone Type 4192 Ordering Information Other Accessories UA 0254 Set of 6 Windscreens UA 0237 90mm 3 5in UA 0469 Set of 6 Windscreens UA 0459 65 mm 2 6in BE 1378 12 Falcon Range of Microphone Products 6 29 Microphone Handbook Chapter 6 Pressure field Ln Microphone Type 4192 Ordering Information 6 30 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 7 Low frequency Pressure field 12 Microphone Type 4193 BE1379 12 Falcon Range of Microphone Products F f Microphone Handbook Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Introduction 7 1 Introduction 7 1 1 Description Fig 7 1 Low frequency Pressurefidd 1 2 Microphone Type 4193 with Protection Grid DB 3421 and Adaptor UC 0211 included Low frequency Pressure field 1 2 Microphone Type 4193 is an externally polarized 1 2 pressure field microphone With its low inherent noise and frequency range extending all the way from 70mHz to 20kHz it is very well suited for measuring infrasound for example in ships engine rooms in helicopters and in wind buffeted buildings Furthermore it satisfies the requirements of ANSI S 1 4 Type 1 and ANSI S 1 12 Type M This microphone is supplied with a special Low frequency Adaptor UC 0211 which because of the extra capaci
26. Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 1 Introduction The Microphones 1 3 5 Microphone data Disk Introduction A 31 2 data disk which supplements the calibration chart is supplied with all mi crophones in the Falcon Range except Prepolarized Freefield 12 Microphone Type 4188 It contains calibration data in the V DATA directory and a presentation program Bruel amp Kj r Microphone Viewer in the root directory The calibration data on each disk is described in the relevant chapters of the handbook The Bruel amp Kj r Micro phone Viewer program must be installed on your computer s hard disk before use using the installation program SETUP EXE supplied on the data disk see below Computer Requirements Bruel amp Kj r Microphone Viewer requires e Windows version 3 1 installed on your computer e 31 2 1 4Mbyte disk drive e 1 5Mbytes free disk space e VGA or SVGA display minimum 640x 480 pixels Installing Bruel amp Kj r Microphone Viewer l Insert the data disk in drive A 2 Start Windows 3 Click on the File menu in the Program M anager 4 Select Run and type AA SETUP EXE 5 Click on OK 6 When SETUP EXE asks you where you want to install the program dick on OK Unless you have selected another directory SETUP EXE installs the program in CABK MIC Two files VBRUN3OO DLL and VER DLL are installed in the WINDOWS SYSTEM directory These files are common for
27. Type 2669 8 1 Nose cone 9 2 O Open circuit sensitivity 4188 prepolarized microphone 2 4 4189 prepolarized microphone 3 5 4190 free field microphone 4 5 4191 free field microphone 5 5 4192 pressure field microphone 6 5 4193 pressure field microphone 7 5 Optimized frequency response 4188 prepolarized micrphone 2 6 4189 prepolarized micrphone 3 7 4190 free field microphone 4 7 4191 free field microphone 5 7 4192 pressure field micrphone 6 7 4193 pressure field micrphone 7 7 Ordering information 2669 preamplifier 8 11 4188 prepolarized microphone 2 28 4189 prepolarized microphone 3 28 4190 free field microphone 4 28 4191 free field microphone 5 28 4192 pressure field microphone 6 28 4193 pressure field microphone 7 32 Output maximum 2669 preamplifier 8 6 Output voltage Index 4 Falcon Range of Microphone Products Bruel amp Kj r Microphone Handbook Index 4188 prepolarized microphone 2 2 2 7 2 20 4189 prepolarized microphone 3 2 3 8 3 20 4190 free field microphone 4 8 4 19 4191 free field microphone 5 8 5 19 6 19 1 23 4192 pressure field microphone 6 8 4193 pressure field microphone 7 9 P Phase response Preamplifier Type 2669 8 8 Physical dimensions microphones 1 6 Preamplifier Type 2669 8 3 Pin designations Preamplifier Type 2669 8 3 Polarization voltage 4188 prepolarized microphone 2 20 4189 prepolarized microphone 3 20 4190 free field microphon
28. 26 Sc 6 2 Ko 26 S 6 3 Example Correction factor for typical microphone with 1 2 Microphone Preamplifier Type 2669 K 26 38 5 2 5dB Open circuit correction factor for typical microphone with 1 2 Microphone Preampli fier Type 2669 Ko 26 38 3 12 3dB 6 3 Frequency Response 6 3 1 General In acoustic measurements there are three types of sound field e Free field e Pressure field e Diffuse field The microphone is optimized to have a flat frequency response in one of these sound fields This response is called the optimized response A microphone s re sponse in a diffuse field is equivalent to its random incidence response This section shows the microphone s typical free field pressure field and random incidence responses together with the microphone s typical actuator response ob tained using Electrostatic Actuator UA 0033 The low frequency response described in section 6 3 4 is common for all types of response 6 6 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 6 Pressure field 1 2 Microphone Type 4192 Frequency Response All frequency responses and correction curves are shown with a frequency resolu tion of 1 12 octave 6 3 2 Optimized Response Pressure field Response Response dB 5 Tol Tol Tol Tol
29. 4192L BKT Low frequency response 1Hz 190 Hz Table 6 1 Calibration data and corrections contained on the data disk Note HHHHYH is the micro phone s serial number a Individual calibration data measured b Low frequency response combined with actuator response and free field corrections c Typical response for Pressure field 1 2 Microphone Type 4192 d Corrections for Pressure field 1 2 Microphone Type 4192 These text files can be viewed on Microsoft Windows using the Br el amp Kjaer Microphone Viewer program BK MIC EXE supplied on the disk They can also be accessed by a suitable spreadsheet for further processing or printing 6 4 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 6 Pressure field oy Microphone Type 4192 Sensitivity Bruel amp Kj r Microphone Viewer must be installed before use see section 1 3 5 6 1 4 Recommended Recalibration Interval With normal handling of the microphone and any associated instrument Bruel amp Kj r recommends that the microphone be recalibrated every 2 years Pressure field 1 2 Microphone Type 4192 is very stable over this period see section 6 10 to section 6 12 Improper handling is by far the most likely cause of change in the microphone s properties Any damage which causes improper operation can probably be detected using a sound level calibrator In many cases the damage can be seen by carefully inspectin
30. BE1376 12 Falcon Range of Microphone Products 4 27 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Electromagnetic Compatibility 4 16 Electromagnetic Compatibility See Chapter 8 4 17 Specifications Overview OPEN CIRCUIT SENSITIVITY 250 Hz 26dB 1 5dB re 1 V Pa 50mV Pa POLARIZATION VOLTAGE External 200 V FREQUENCY RESPONSE 0 incidence free field response 5Hz to 10kHz 1dB 3 15Hz to 20kHz 2dB In accordance with IEC 651 Type 0 and Type 1 LOWER LIMITING FREQUENCY 3 dB 1Hz to 2Hz vent exposed to sound PRESSURE EQUALIZATION VENT Rear vented DIAPHRAGM RESONANCE FREQUENCY 14 kHz typical 90 phase shift CAPACITANCE POLARIZED 16 pF typical at 250 Hz EQUIVALENT AIR VOLUME 101 3 kPa 46 mm ndividually calibrated CALIBRATOR LOAD VOLUME 250 Hz 250 mm PISTONPHONE TYPE 4228 CORRECTION with DP 0776 0 00 dB TYPICAL CARTRIDGE THERMAL NOISE 14 6dB A 15 3dB Lin UPPER LIMIT OF DYNAMIC RANGE 3 distortion gt 148dB SPL MAXIMUM SOUND PRESSURE LEVEL 159 dB peak OPERATING TEMPERATURE RANGE 30 to 150 C 22 to 302 F can be used up to 300 C 572 F but with a permanent sensitivity change of typically 0 4 dB which stabilises after one hour OPERATING HUMIDITY RANGE 0 to 100 RH without condensation STORAGE TEMPERATURE 30 to 70 C 22 to 158 F TEMPERATURE COEFFICIENT 250 Hz 0 007dB C t
31. Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Frequency Response 7 3 7 Pressure field Response Correction dB 4 The microphone s pressure field correction curve is shown in Fig 7 12 This correc tion is added to the microphone s actuator response obtained using Electrostatic Actuator UA 0033 in order to determine the pressure field response The typical pressure field response is shown in Fig 7 13 In practice the pressure field response is often regarded as being equal to the actuator response as the difference between them is small compared to the uncer tainty related to many types of measurement 100 Response dB 8 1k 10k 100 k Frequency Hz 940868e Fig 7 12 Pressurefield correction for the microphone 20 100 ix 10k H 100 k requency Hz 940872e Fig 7 13 Typical pressurefield response for the microphone Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field lp Microphone Type 4193 Directional Characteristics 7 4 Directional Characteristics Typical directional characteristics are given in Fig 7 14 and Fig
32. Range of Microphone Products 6 23 Microphone Handbook Chapter 6 Pressure field z Microphone Type 4192 Effect of Temperature Response dB 1 5 0 5 0 0 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940776e Fig 6 23 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 6 4 over the temperature range defined by IEC 651 Response dB 500 1k 10k Frequency Hz 50k 940600e Fig 6 24 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 6 4 6 24 Falcon Range of Microphone Products Microphone Handbook Br el amp Kj r Chapter 6 Pressure field Tor Microphone Type 4192 Effect of Ambient Pressure The effect of temperature on the free field response see Fig 6 25 of the microphone is the sum of the following effects e the calculated effect of the change in the speed of sound due to temperature on the 0 incidence free field correction e the measured change in the actuator response due to temperature see Fig 6 23 Response dB 15 10 C 0 5
33. The preamplifier can be stored in the supplied case with a microphone mounted when not in use 8 2 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 8 lp Microphone Preamplifier Type 2669 Introduction Alternativley the preamplifier can be stored in the microphone s case with the mi crophone when not in use 8 1 2 Connections ee OO mmeews omo 3 l Swan Rima Low 7 Signal Output Signal Output fF 08 0 Not connected Power Supply Positive Power Supply Positive Not connected P S Iv N Cable s output plug ower Su ega i 7 pply g Not connected seen from outside TE tive Ground Casing Connected to instrument chassis Table 8 1 Pin designations 8 1 3 Physical Dimensions 940993e Fig 8 2 Physical dimensions of the preamplifier and connector BE 1380 12 Falcon Range of Microphone Products 8 3 Microphone Handbook Chapter 8 b Microphone Preamplifier Type 2669 Frequency Response 8 2 Frequency Response The frequency response of the preamplifier depends on the capacitance of the micro phone connected to its input and the capacitive load for example extension cables connected to the output pe 10 nF 0 3 nF 8 m Standard Cable aB 47 pF 30 nF 15 pF 5 6 2 pF 10 12 0 1 1 10 20 20k 100k Frequency Hz 9410216 Fig
34. V 9406816 Fig 4 20 Variation in sensitivity at 250Hz as a function of po larization voltage relative to the sensitivity with a polar ization voltage of 200V Response dB 2 5 2 28 V 1 0 150V 1 250 V 2 2 5 100 1k Hz 10k 100k Frequency Hz Sanie Fig 4 21 Effect of polarization voltage on frequency response The curves show the difference from the response with a polarization voltage of 200V normalised at 250 Hz 4 20 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 4 Free field 1 2 Microphone Type 4190 Leakage Resistance 4 9 Leakage Resistance To maintain the correct polarization voltage on the microphone the microphone s leakage resistance must be at least 1000 times greater than the supply resistance of the polarization charge even under the most severe environmental conditions This resistance which is generally placed in the preamplifier is typically 10 to 1019 o Bruel amp Kj r microphones have a very high leakage resistance which is greater than 5x10 Q at 90 RH and 23 C 4 10 Stability 4 10 1 Mechanical Stability The microphone s design with respect to mechanical stability is improved compared with traditional Bruel amp Kjar microphones The diaphragm damping ring is less sensitive to accidental force and t
35. for free field random incidence and pressure field conditions The stated uncertainty is the Uos value the value valid for 95 confidence level Ambient Conditions The ambient conditions are measured continuously during calibration at the factory The calibration results obtained at the measured Environmental Calibration Condi tions are corrected to the reference ambient conditions stated under Valid At 23 C 101 325 kPa and 5096RH The exact reference frequency is 102 Hz re ISO 266 BE 1379 12 Falcon Range of Microphone Products 7 3 Microphone Handbook Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Introduction Frequency Responses Two frequency responses are shown on the calibration chart Both are normalized to OdB at the reference frequency 251 2 Hz The lower curve on the calibration chart is the individual microphone s open circuit pressure field response This response is the optimized response for Low frequency Pressure field 1 2 Microphone Type 4193 The upper curve on the calibration chart is the random incidence response Both curves are determined by adding the relevant correction curve to the individu al actuator response measured with Electrostatic Actuator UA 0033 The individual microphones electrostatic actuator response is also available on the data disk The dotted part of the curve is the typical low frequency response Each micro phone s individual lower limit
36. reamplifier Frequency Hz 940716e Fig2 18 l 3 octave band inherent noise spectrum The shaded bar graphs are the broad band 20Hz to 20kHz noise levels and the white bar graphs the A weghted noise levels of the microphone M 1 2 Microphone Preamplifier Type 2669 P and microphone and pream plifier combination C BE 1374 12 Falcon Range of Microphone Products 2 17 Microphone Handbook Chapter 2 Prepolarized Freefield Ape Microphone Type 4188 Dynamic Range Distortion The distortion is determined mainly by the microphone but at the highest opera tion levels the preamplifier also contributes to the distortion see Fig 2 19 Distortion 96 10 pnd Harmonic 0 1 0 01 125 135 145 SPL dB 155 940400e Fig 2 19 Typical distortion characteristics of the microphone both open circuit and with Y2 Microphone Preamplifier Type 2669 The distortion is dependent on the capacitance parallel to the microphone It in creases with increasing capacitance The distortions given in Table 2 2 and Table 2 3 are valid for a parallel capacitance of 0 5pF The distortion is measured at 100Hz but can be assumed to be valid up to approximately 5kHz that is where the diaphragm displacement is predominantly stiffness controlled Distortion meas urement methods for higher frequencies are not available
37. you want to meas ure at frequencies down to 0 07Hz for infrasound measurements choose Low frequency Pressure field 1 2 Microphone Type 4193 or at frequencies up to 40kHz for harmonic distortion measurements on loudspeakers choose Free field 1 2 Mi crophone T ype 4191 Polarization P reamplifier Prepolarized microphones are required on certain portable sound level meters which do not provide external polarization and are a good choice in tough and BE 1372 12 Falcon Range of Microphone Products 1 3 Microphone Handbook Chapter 1 Introduction The Microphones humid environments Externally polarized microphones are more stable also at high temperatures All can be used with Br el amp Kjae s 12 Microphone Preamplifi er Type 2669 The two prepolarized microphones Types 4188 and 4189 can also be used with Br el amp Kjaer s Preamplifier Type 2671 Free field Response or Pressure field Response The four free field response microphones Types 4188 to 4191 cover spedific IEC requirements and should be used in sound fields where reflections are negligible The two pressure field response microphones Types 4192 and 4193 should be used for measurements in acoustic couplers They also cover specific ANSI requirements and can be used in diffuse sound fields As Replacements for Traditional Bruel amp Kj r Microphones Table 1 1 shows what traditional Br el amp Kjaer microphones type approval permit ting
38. 0g EAA MI MI WOMAN M NI MU M HIT Ii WIN I I 6 3 kHz WEN 8 kHz 10 kHzz 1 RT m 5 kHz M ITA Tii I TU TI of I HN V 940778e Fig 2 15 Typical directional characteristics of the microphone with Protection Grid DD 0525 HTT i E M INTTR TEL BA A 27 ULLA m Wot ll A TII 2l ALN AN Wi M IM I il HTT HN ITT iai K 203E 250g HHS Tos Hl UU m MIT Y I 270 WII Jj MI Wl i Iii i lel il I MEX Mil x SE N 940779e Fig 2 16 Typical directional characteristics of the microphone without protection grid 2 14 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook BE 1374 12 Chapter 2 Prepolarized Free field Ton Microphone Type 4188 Directional Characteristics Ii EHI HIT l HH AN TTT 5 HG ME mill nn Vete Hit p A D MAT BNI 10141 18011 2015 252506 L A NUI WHO Me HTT IBI FEET INTL TI Ard n E M ii AAA WAY 8 kHz NN 6 3 kHz 10 kHz WU KP ELLA WM Wu R4 ANY AS HE O HH 0 E nl APA g HTH THAM l 2018 258102 J Fig 2 17 Typical directional characteristics of the microphone with DZ 9566 940781e Random Incidenc
39. 2 Microphone Type 4191 meets the require ments of IEC 651 Type 0 and Type 1 and ANSI S1 12 Type M 5 3 3 Actuator Response The microphone s frequency response is determined by adding corrections for the type of sound field to its actuator response obtained using Electrostatic Actuator UA 0033 This is a reproducible and practical method for calibrating a microphone s frequency response BE 1377 12 Falcon Range of Microphone Products 5 7 Microphone Handbook Chapter 5 Free field Tj Microphone Type 4191 Frequency Response Response dB 5 10 15 100 1k 10k 100 k Frequency Hz 940672e Fig 5 4 Typical actuator response magnitude measured with Electrostatic Actuator UA 0033 Response Degrees 0 45 90 135 180 100 1k 10k 100k Frequency Hz 940673e Fig 5 5 Typical actuator response phase measured with Electrostatic Actuator UA 0033 If the polarization voltage is positive as it is with Br el amp Kj r instruments the output voltage is negative for a positive pressure applied to the diaphragm 5 3 4 Low frequency Response The low frequency response see Fig 5 3 is the typical response with the vent ex posed to the sound
40. 26 4189 prepolarized microphone 3 26 4190 free field microphone 4 27 4191 free field microphone 5 27 4192 pressure field microphone 6 27 4193 pressure field microphone 7 30 l Inherent noise 5 15 8 5 4188 prepolarized microphone 2 16 4189 prepolarized microphone 3 15 4190 free field microphone 4 14 4191 free field microphone 5 14 4192 pressure field microphone 6 14 4193 pressure field microphone 7 16 K K factor 4188 prepolarized microphone 2 5 4189 prepolarized microphone 3 6 4190 free field microphone 4 6 4191 free field microphone 5 6 4192 pressure field microphone 6 6 4193 pressure field microphone 7 6 L Leakage resistance 4188 prepolarized microphone 2 21 4189 prepolarized microphone 3 21 4190 free field microphone 4 21 4191 free field microphone 5 21 BE 1382 12 Falcon Range of Microphone Products Microphone Handbook Index 3 Index 4192 pressure field microphone 6 21 4193 pressure field microphone 7 24 LEMO Br el amp Kj r adaptor 9 2 LEMO Br el amp Kjar cable 9 2 LEMO LEMO cable 9 2 LEMO LEMO extension cable 9 2 Load volume calibrator 4188 prepolarized microphone 2 19 4189 prepolarized microphone 3 19 4190 free field microphone 4 18 4191 free field microphone 5 18 4192 pressure field microphone 6 18 4193 pressure field microphone 7 22 Loaded sensitivity 4188 prepolarized microphone 2 4 4189 prepolarized microphone 3 5 4190 free field microphone 4 5 4191 f
41. Accessories Prepolarized Prepolarized Leid Free field Pressure Low frequency Accessory Free field Free field Micro Micro Micro Pressure Microphone Microphone phone phone phone Microphone Type 4188 Type 4189 Type 4190 Type 4191 Type 4192 Type 4193 Windscreen UA 0237 UA 0459 Rain Cover UA 0393 Dehumidifier UA 0308 Turbulence Screen UA 036 Nose Cone UA 0386 Table 9 1 Accessories available for the various microphones 9 1 2 Cables and Adaptors AO 0428 Included with Preamplifier Type 2669 B i i m AO 0414 LEMO LEMO extension cable 3 m AO 0416 LEMO LEMO extension cable 30 m AR 0014 LEMO LEMO flat cable 0 5m Table 9 2 Cables and adaptors available from Br el amp Kj r 9 2 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook ndex 1 2 Microphone Preamplifier Type 2669 8 1 4190 free field microphone 4 7 2669 1 2 Microphone Preamplifier 8 1 4191 free field microphone 5 7 4188 4192 pressure field microphone 6 7 Prepolarized Free field 1 2 Microphone 2 1 4193 pressure field microphone 7 9 4189 Adaptor 9 2 Prepolarized Free field 1 2 Microphone 3 1 LEMO Br el amp Kjar 9 2 4190 microphone 8 12 Free field 1 2 Microphone 4 1 UC 0211 7 5 4191 Ambient pressure Free field 1 2 Microphone 5 1 4188 prepolarized microphone 2 25 4192 4189 prepolarized microphone 3 25 Pressure field 1 2 Microphone 6 1 4190 free field microphone 4 25 4193 4191
42. Handbook 4 1 Chapter 4 Free field 1 5 Microphone Type 4190 Introduction 4 1 ntroduction 4 1 1 Description 9408578 Fig 4 1 Fre fied 1 2 Microphone Type 4190 with Protection Grid DB 3420 included Free field 1 2 Microphone Type 4190 is an externally polarized microphone for gen eral sound measurements and for standardized noise measurements in accordance with the requirements of IEC 651 Type 0 and Type 1 With its low inherent noise and frequency range from 3 15Hz to 20kHz it is very well suited for a wide range of precision audio frequency sound measurements The microphone requires a polarization voltage of 200 V provided by the instrument or analyzer powering the associated preamplifier This rugged microphone is built to ensure high stability under a variety of condi tions For example the stainless steel alloy diaphragm withstands polluted industri al environments The diaphragm damping ring is firmly secured to ensure the microphones reliability even when the microphone is used without its protection grid When the microphone is used without its protection grid it can be easily flush mounted or inserted into closed volumes as it can be supported by the dia phragm damping ring provided that a force of less than 5Newtons is applied The microphone is supplied with individual calibration data on a calibration chart and on a 3l data disk in a case This case can also contain a 1 2 Microphone
43. IN matio P 4 28 5 Free field lp Microphone Type 4191 5 1 5 ETUC A PD 5 2 5 2 PTS UMN MEER 5 5 EE Freguenty RESPONSE em 5 6 5 4 Direcional Character SEIS E 5 13 5 5 Dynamit SU IEU ETDETTLTLLTTTTD 0L 2 E aA A E a a 5 14 5 6 Equivalent Volume and Calibrator Load Volume sse 5 17 57 AAA ARVC Cage sce sasevenetaneuvacadaacspsicuisexnsyuvexeadadad ENa EN ENRE a EEE E N a naan 5 19 5 8 Polarization Voltage nanana 5 19 5 9 L akadgep esl SEalICB iei esr OR REX a E nexa R E NE EFE TRE TNR RERDRM KK caa 5 21 5 10 n e a d HH 5 21 5 11 E nect or Temperature sciiicet ro RR Re E Rn ER NE RRRN IR es ne bri ER REM esa 5 22 5 12 Effect of Ambient Pressure eessseseeeeeeeeeeneen enne enne nnns 5 25 5 13 cadi dais 5 27 5 14 Effect OF dore rE 5 27 5 15 u edidsgaz4adln 5 27 0 4 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Contents 5 16 Elect comagnetic CormpalbiBi Vb scooter te entertain a eroe tpe etate 5 28 nl Se eE ERE E ON M 5 28 5 18 Ordaringllnior matio NETS 5 28 6 Pressure field 1 5 Microphone Type 4192 6 1 6 1 RTE OCMICC VOI p a aaa R E EEE N KA 6 2 6 2 cpi A E A E 6 5 6 3 PVT e gci gn lS 6 6 6 4 Directional GCharacterlsEs usce reacted engages ta eo RERO EXTR RE RR FO TERR PERS i 6
44. Introduction About the Microphone Handbook 1 1 About the Microphone Handbook This handbook contains specific information about Bruel amp Kjaer s Falcon Range of 1 2 microphone products It contains a chapter on each of the microphones a chap ter on 1 2 Microphone Preamplifier Type 2669 which can be used with these micro phones and a list of the available accessories which can also be used with these microphones 1 2 About the Falcon Range of Microphone Products Bruel amp Kjaer s Falcon Range of microphone products includes six 1 2 condenser microphones and a microphone preamplifier covering between them a very wide range of needs and applications They are the culmination of over 40 years of leadership in top quality condenser microphones and preamplifiers for precision acoustic measurements The Falcon Range of microphone products will meet your demands whether they be in comply ing with ANSI or IEC standards or in acoustic research 1 3 The Microphones 1 3 1 Robust and Stable The microphones in the Falcon Range are robust and can even withstand an IEC 68 2 32 1m drop test onto a hard wooden block without suffering more than 0 1dB change in sensitivity They are made of carefully selected materials and alloys to ensure excellent stability and are virtually unaffected by industrial and similarly hostile environments During manufacture each microphone is artificially aged at a high temperature to ensure good lo
45. Maximum Sound Pressure L evel In general the microphone should not be exposed to sound pressure levels which produce voltages higher than the maximum input voltage specified for the connect ed preamplifier After an overload the preamplifier needs time to recover and dur ing this recovery period you cannot measure validly The maximum input voltage for most Bruel amp Kj r preamplifiers is 50V with a 130V supply This voltage is 2 18 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 2 Prepolarized Free field 1p Microphone Type 4188 Equivalent Volume and Calibrator Load Volume Lower Limit Upper Limit 1 Hz bandwidth Ts octave st A weighted dB Linear 20 pa r lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB Low qom o9 do 1 Table 2 2 Dynamic range of the microphone Lower Limit Upper Limit 1 Hz bandwidth Ts Octave ES A weighted dB Linear 20 dE lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB Exi jo Table 2 3 Dynamic range of the microphone with 1 2 Microphone Preamplifier Type 2669 produced by a nominal Prepolarized Free field 1 Microphone Type 4188 at a Peak level of 158dB re 20g Pa The microphone s distortion increases smoothly as a function of sound pressure level until the diaphragm s displacement becomes so large that it hits the back plate When this occurs at a Peak level of 157dB th
46. Microphone Preamplifier Type 2669 P and microphone and pream plifier combination C BE 1378 12 Falcon Range of Microphone Products 6 15 Microphone Handbook Chapter 6 Pressure field z Microphone Type 4192 Dynamic Range Distortion The distortion is determined mainly by the microphone but at the highest opera tion levels the preamplifier also contributes to the distortion see Fig 6 17 Distortion 96 10 gnd Harmonic 0 1 0 01 135 145 SPL dB 155 165 940499e Fig 6 17 Typical distortion characteristics of the microphone with 1 2 Microphone Preamplifier Type 2669 C and unload ed M The distortion is dependent on the capacitance parallel to the microphone It in creases with increasing capacitance The distortions given in Table 6 3 and Table 6 4 are valid for a parallel capacitance of O 5pF The distortion is measured at 100Hz but can be assumed to be valid up to approximately 5kHz that is where the diaphragm displacement is predominantly stiffness controlled Distortion meas urement methods for higher frequencies are not available Maximum Sound Pressure Level In general the microphone should not be exposed to sound pressure levels which produce voltages higher than the maximum input voltage specified for the connect ed preamplifier After an overload the preamplifier needs time to recover and du
47. Relative Humidity 50 Frequency 250 Hz Polarization Voltage external 200 V Sensitivity Traceable To DPLA Danish Primary Laboratory of Acoustics NIST National Institute of Standards and Technology USA IEC 1094 4 Type WS 2 P Environmental Calibration Conditions 100 1 kPa 25 C 35 RH Procedure 704218 Date 21 Apr 1994 Signature Ko 26 So Example Ko 26 38 12 dB BC 0227 12 Dotted Curve Shows pical Response a ene i ET 2 5 10 20 50 10k 20k 40k See the microphone handbook for further information Frequency Hz BOIS 940953 1e Fig 6 2 Microphone calibration chart Open circuit Sensitivity The stated open circuit sensitivity is valid at the reference frequency 251 2 Hz for free field random incidence and pressure field conditions The stated uncertainty is the Us value the value valid for 95 confidence level Ambient Conditions The ambient conditions are measured continuously during calibration at the factory The calibration results obtained at the measured Environmental Calibration Condi tions are corrected to the reference ambient conditions stated under Valid At 23 C 101 325kPa and 50 RH Frequency Responses Two frequency responses are shown on the calib
48. Sc 38 3 16 5 2 54 8dB 7 2 3 K factor Some types of Bruel amp Kj r instruments use the K factor correction factor or the Ko factor open circuit correction factor for calibration K 26 Sc 7 2 Ko 26 Sg 7 3 7 6 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 7 Low frequency Pressure field v Microphone Type 4193 Frequency Response Example Correction factor for typical microphone with 1 2 Microphone Preamplifier Type 2669 K 26 38 5 12 5 dB Open circuit correction factor for typical microphone with 1 2 Microphone Preampli fier Type 2669 Ko 26 38 3 12 3dB 7 3 Frequency Response 7 3 1 General In acoustic measurements there are three types of sound field e Free field e Pressure field e Diffuse field The microphone is optimized to have a flat frequency response in one of these sound fields This response is called the optimized response A microphones re sponse in a diffuse field is equivalent to its random incidence response This section shows the microphone s typical free field pressure field and random incidence responses together with the microphone s typical actuator response ob tained using Electrostatic Actuator UA 0033 The low frequency response described in section 7 3 4 is common for all types of response All frequency responses and correction curves shown are valid for a microphone without Adaptor UC 0211 fitte
49. Table 4 2 Nominal open circuit sensitivity 4 2 2 Loaded Sensitivity When loaded by a preamplifier the sensitivity of the microphone is given by where Sc overall sensitivity of microphone and preamplifier combination So open circuit sensitivity of microphone G voltage gain of microphone and preamplifier combination in dB With Microphone Preamplifier Type 2639 G 0 1dB With 1 2 Microphone Preamplifier Type 2669 G 0 2 dB BE 1376 12 Falcon Range of Microphone Products 4 5 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Frequency Response Example Loaded sensitivity of typical microphone with 1 2 Microphone Preamplifier Type 2669 Sc 26 3 0 2 26 5 dB 4 2 3 K factor Some types of Br el amp Kj r instruments use the K factor correction factor or the Ko factor open circuit correction factor for calibration K 26 Sc 4 2 Ko 26 So 4 3 Example Correction factor for typical microphone with 1 2 Microphone Preamplifier Type 2669 K 26 26 5 40 5 dB Open circuit correction factor for typical microphone with 1 2 Microphone Preampli fier Type 2669 Ko 26 26 3 0 3 dB 4 3 Frequency Response 4 3 1 General In acoustic measurements there are three types of sound field e Free field e Pressure field e Diffuse field The microphone is optimized to have a flat frequency response in one of these sound fields This response is called t
50. Tj Microphone Type 4188 Ordering Information 2 30 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 3 Prepolarized Free field 1 2 Microphone Type 4189 BE 1375 12 Falcon Range of Microphone Products 3 1 Microphone Handbook Chapter 3 Prepolarized Free field Ape Microphone Type 4189 Introduction 3 1 Introduction 3 1 1 Description Fig 3 1 Prepolarized Freefidd 1 2 Microphone Type 4189 with Protection Grid DB 3420 included Prepolarized Free field 1 2 Microphone Type 4189 is a prepolarized 1 2 free field microphone and offers some significant advantages when used with portable instru ments For example smaller associated instruments with low power consumption can be used A general advantage is the improved reliability of the associated preamplifier in humid and polluted atmospheres These factors make this prepolar ized condenser microphone particularly suitable for field measurements both out doors and in industrial environments In addition it is suited to IEC 651 Type 1 measurements and frequency analysis measurements This microphone is polarized by a fixed charge carrying layer deposited on the back plate This layer is negatively charged which at low frequencies results in a posi tively increasing output voltage for a positively increasing incident sound pressure As a prepolarized microphone it is externally marked by a pair of grooves The ru
51. at 251 2Hz and stated on the microphone s calibration chart see section 5 1 2 and data disk see section 5 1 3 The nominal sensitivity is shown in Table 5 2 Nominal open circuit sensitivity Accepted Deviation dB Table 5 2 Nominal open circuit sensitivity 5 2 2 Loaded Sensitivity When loaded by a preamplifier the sensitivity of the microphone is given by where Sc overall sensitivity of microphone and preamplifier combination So open circuit sensitivity of microphone G voltage gain of microphone and preamplifier combination in dB With Microphone Preamplifier Type 2639 G 0 1dB With 1 2 Microphone Preamplifier Type 2669 G 0 2dB BE 1377 12 Falcon Range of Microphone Products 5 5 Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Frequency Response Example Loaded sensitivity of typical microphone with 1 2 Microphone Preamplifier Type 2669 Sc 38 3 0 2 38 5dB 5 2 3 K factor Some types of Bruel amp Kj r instruments use the K factor correction factor or the Ko factor open circuit correction factor for calibration K 26 S 5 2 Ko 26 S 5 3 Example Correction factor for typical microphone with 1 2 Microphone Preamplifier Type 2669 K 26 38 5 2 5dB Open circuit correction factor for typical microphone with 1 2 Microphone Preampli fier Type 2669 Ko 26 38 3 12 3dB 5 3 Frequency Response 5 3 1 General In acoustic mea
52. at temperatures up to 300 C Below 170 C no changes occur At 170 C the sensitivity can be permanently changed within the first 10 hours by less than 0 025 dB After this the sensitivity can be permanently changed within the next 100 hours by a similar value At 300 C the sensitivity can be permanently changed within the first hour by 0 4dB After this the sensitivity can be permanently changed within the next 10hours by less than 0 4 dB BE 1377 12 Falcon Range of Microphone Products 5 21 Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Effect of Temperature Note Spedial adaptors inserted between the microphone and preamplifier must be made for high temperature applications in order to protect the preampifier from heat conduction and radiation 5 10 3 Long term Stability Over a period of time the mechanical tension in the diaphragm will decrease due to stretching within the foil This mechanism which in principle causes an increased sensitivity is however very weak for the microphone Measurement of this mecha nism is not possible at room temperature At present no exact value can be given for the microphone s long term stability but measured changes at high temperatures indicate that Free field 1 2 Microphone Type 4191 is more than 10 times more stable than traditional Br el amp Kjaer micro phones This indicates typical changes of less than 1dB in 5000 years 5 11 Effect of Temp
53. be used up to 300 C 572 F but with a permanent sensitivity change of typically 0 4 dB which stabilises after one hour DIAPHRAGM RESONANCE FREQUENCY 23 kHz typical 90 phase shift CAPACITANCE POLARIZED 18 pF typical at 250 Hz OPERATING HUMIDITY RANGE 0 to 100 RH without condensation EQUIVALENT AIR VOLUME 101 3 kPa 8 8 mm STORAGE TEMPERATURE 30 to 70 C 22 to 158 F TEMPERATURE COEFFICIENT 250 Hz 0 002dB C typical for the range 10 to 50 C Individually calibrated 6 18 Ordering Information Preamplifier Type 2669 1 Microphone Preamplifier Calibration Equipment Type 4231 Sound Level Calibrator Type 4226 Multifunction Acoustic Calibrator Type 4228 Pistonphone UA 0033 Electrostatic Actuator PRESSURE COEFFICIENT 250 Hz 0 005 dB kPa typical INFLUENCE OF HUMIDITY 0 1 dB 100 RH VIBRATION SENSITIVITY 1000 Hz Typically 65 5 dB equivalent SPL for 1 m s axial acceleration MAGNETIC FIELD SENSITIVITY Typically 16 dB SPL for 80 A m 50Hz field ESTIMATED LONG TERM STABILITY gt 1 000 years dB at 20 C gt 1 00 hours dB at 150 C DIMENSIONS Diameter 13 2 mm 0 52in with grid 12 7 mm 0 50 in without grid 13 5 mm 0 54 in with grid 12 6 mm 0 50 in without grid Thread for preamplifier mounting 11 7 mm 60 UNS Height The data above are valid at 23 C 101 3 kPa and 5096 RH unless otherwise specified Falcon
54. behind the diaphragm and changes in air mass in the small gap between the diaphragm and the back plate The effects are shown in Fig 4 26 to Fig 4 28 BE 1376 12 Falcon Range of Microphone Products 4 25 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Effect of Ambient Pressure The typical pressure coefficient at 250Hz for Freefield 1 2 Microphone Type 4190 is 0 010 dB kPa well within the x 0 03 dB kPa limits required for Type 0 and Type 1 sound level meters by IEC 651 Correction dB 3 40kPa change 1 20kPa change E 7z 10kPa Pa change 500 1k 10k Frequency Hz 50k 940763e Fig 4 26 Typical variation in frequency response normalized at 250 Hz from that at 101 3kPa as a function of changein ambient pressure Response dB 30 1k 10k Frequency Hz 50k 940755e Fig 4 27 Typical effect of ambient pressure on actuator response normalized at 250Hz a at 101 3kPa b 40kPa change c 80kPa change d at 2 kPa 4 26 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 4 Free field 1 2 Microphone Type 4190 Effect of Humidity Response dB 4
55. by 0 5dB at 55 C and by 0 5dB at 12 C The maximum variation of inherent noise for different samples of Low frequency Pres sure field 1 2 Microphone Type 4193 is 1dB The preamplifier s effect on the inherent noise of the combined microphone and preamplifier depends on the sensitivity and capacitance of the microphone for 1 2 Microphone Preamplifier Type 2669 see Fig 7 16 and Chapter 8 When used with 12 Microphone Preamplifier Type 2669 and Adaptor UC 0211 the preamplifier s inherent noise dominates see Table 7 4 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field ty Microphone Type 4193 Dynamic Range Sound Pressure Level 30 re 20 uPa dB L 25 L L 20 A A A 15 10 Microphone and Preamplifier Combination 5 Microphone Preamplifier o EN 10 100 1k 10k 20k M P C Frequency Hz 940720e Fig 7 16 1 3 octave band inherent noise spectrum The shaded bar graphs are the broad band 20Hz to 20kHz noise levels and the white bar graphs the A weghted noise levels of the microphone M 1 2 Microphone Preamplifier Type 2669 P and microphone and pream plifier combination C Valid for microphone without Adaptor UC 0211 BE1379 12 Falcon Range of Microphone Products 7 17 Microphone Handbook Chapter 7 Low frequency Pressure
56. direction is normal to the diaphragm A magnetic field strength of 80A m at 50Hz the test level recommended by IEC and ANSI normal to the diaphragm produces a typical equivalent Sound Pressure Lev el of 16dB Higher frequency components in the microphone output become domi nant at field strengths greater than 500 to 1000 A m BE 1377 12 Falcon Range of Microphone Products 5 27 Microphone Handbook Chapter 5 Free field 1p Microphone Type 4191 Electromagnetic Compatibility 5 16 Electromagnetic Compatibility See Chapter 8 5 17 Specifications Overview OPEN CIRCUIT SENSITIVITY 250 Hz 38dB t1 5dB re 1 V Pa 12 5 mV Pa POLARIZATION VOLTAGE External 200 V FREQUENCY RESPONSE 0 incidence free field response 5Hz to 16kHz 1dB 3 15Hz to 40kHz 2dB In accordance with IEC 651 Type 0 Type 1 and ANSI 81 12 Type M LOWER LIMITING FREQUENCY 3 dB 1Hz to 2Hz vent exposed to sound PRESSURE EQUALIZATION VENT Side vented DIAPHRAGM RESONANCE FREQUENCY 34 kHz typical 90 phase shift CAPACITANCE POLARIZED 18 pF typical at 250 Hz EQUIVALENT AIR VOLUME 101 3 kPa 11 6 mm Individually calibrated CALIBRATOR LOAD VOLUME 250 Hz 190 mm PISTONPHONE TYPE 4228 CORRECTION with DP 0776 40 02 dB TYPICAL CARTRIDGE THERMAL NOISE 20 0dB A 21 4dB Lin UPPER LIMIT OF DYNAMIC RANGE 3 distortion gt 162dB SPL MAXIMUM SOUND PRESSURE LEVEL 171 dB peak OPERATI
57. el amp Kj r Microphone Handbook Chapter 7 Low frequency Pressure field v Microphone Type 4193 Frequency Response 7 3 6 Random incidence Response A microphone s response in a diffuse sound field is equivalent to its random inci dence response The microphone s random incidence correction curves are shown in Fig 7 6 and Fig 7 8 These corrections are added to the microphone s actuator re sponse obtained using Electrostatic Actuator UA 0033 in order to determine the random incidence response The typical random incidence response with and with out the protection grid are shown in Fig 7 10 and Fig 7 11 The random incidence corrections are calculated from the free field corrections measured in 5 steps according to Draft IEC 1183 1993 Response dB 5 dB 100 1k 10k 100 k Frequency Hz 940942 1e Fig 7 10 Typical random incidence response for the microphone with Protection Grid DB 3421 Response dB 5 dB 100 1k 10k 100 k Frequency Hz 940943 1e Fig 7 11 Typical random incidence response for the microphone without protection grid BE 1379 12 Falcon Range of Microphone Products 7 13 Microphone Handbook
58. field microphone 5 11 4192 pressure field microphone 6 11 4193 pressure field microphone 7 13 Range dynamic 4188 prepolarized microphone 2 16 4189 prepolarized microphone 3 15 4190 free field microphone 4 14 4191 free field microphone 5 14 4192 pressure field microphone 6 14 4193 pressure field microphone 7 16 Recalibration 4188 prepolarized microphone 2 4 4189 prepolarized microphone 3 5 4190 free field microphone 4 5 4191 free field microphone 5 5 4192 pressure field microphone 6 5 4193 pressure field microphone 7 5 Resistance leakage 4188 prepolarized microphone 2 21 4189 prepolarized microphone 3 21 4190 free field microphone 4 21 4191 free field microphone 5 21 4192 pressure field microphone 6 21 4193 pressure field microphone 7 24 Response frequency actuator 4188 prepolarized microphone 2 6 BE1382 12 Falcon Range of Microphone Products Index 5 Microphone Handbook Index 4189 prepolarized microphone 3 7 4190 free field microphone 4 7 4191 free field microphone 5 7 4192 pressure field microphone 6 7 4193 pressure field microphone 7 9 free field 4188 prepolarized microphone 2 8 4189 prepolarized microphone 3 9 4190 free field microphone 4 9 4191 free field microphone 5 9 4192 pressure field microphone 6 9 4193 pressure field microphone 7 10 low frequency 4188 prepolarized microphone 2 7 4189 prepolarized microphone 3 8 4190 free field microphone 4 8 4191 free field
59. frequency responses The data is valid for a microphone without Adaptor UC 0211 fitted Low frequency Pressure field 1 2 Microphone Type 4193 Bruel amp Kj r Calibration Chart Serial No 4193000 Open circuit Sensitivity So 38 0 dB re 1V Pa L Equivalent to 12 6 mviPa T II Uncertainty 95 96 confidence level 0 2 dB Pressure fleld Capacitance 18 4 pF Valid At Temperature 23 Ambient Static Pressure 101 3 kPa Relative Humidity 50 96 Frequency 250 Hz Polarization Voltage external 200 V Sensitivity Traceable To DPLA Danish Primary Laboratory of Acoustics NIST National Institute of Standards and Technology USA IEC 1094 4 Type WS 2 P Environmental Calibration Conditions 100 1 kPa 25 35 RH Procedure 704219 Date 21 Apr 1994 Signature Kg 26 S Example Ko 26 38 12 dB BC 0228 12 T T T TT TTE Random incidence Response LLL LLLA f Dotted Curve Shows ypical Response i 2 5 10 20 50 5k 10k 20k 40k See the microphone handbook for further information Frequency Hz 940954 1e Fig 7 2 Microphone calibration chart Open circuit Sensitivity The stated open circuit sensitivity is valid at the reference frequency 251 2 Hz
60. from the freefield corrections measured in 5 steps according to Draft IEC 1183 1993 Response dB 5 dB 100 1k 10k 100k Frequency Hz 940936 1e Fig 3 10 Typical random incidence response for the microphone with Protection Grid DB 3420 Response dB 5 100 1k 10k 100 k Frequency Hz 940937 1e Fig 3 11 Typical random incidence response for the microphone without protection grid 3 12 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 3 Prepolarized Free field v Microphone Type 4189 Frequency Response 3 3 7 Pressure field Response The microphone s pressure field correction curve is shown in Fig 3 12 This correc tion is added to the microphone s actuator response obtained using Electrostatic Actuator UA 0033 in order to determine the pressure field response The typical pressure field response is shown in Fig 3 13 In practice the pressure field response is often regarded as being equal to the actuator response as the difference between them is small compared to the uncer tainty related to many types of measurement Correction dB 4
61. ment methods for higher frequencies are not available Lower Limit Upper Limit 1 Hz bandwidth E octave ds A weighted dB Linear 20 je to lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB dB wm m w m Table 7 3 Dynamic range of the microphone BE 1379 12 Falcon Range of Microphone Products 7 19 Microphone Handbook Chapter 7 Low frequency Pressure field E Microphone T ype 4193 Equivalent Volume and Calibrator Load Volume Lower Limit Upper Limit 1 Hz bandwidth tg octave se A weighted dB Linear 20 dE i lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20kHz dB dB l a o Table 7 4 Dynamic range of the microphone with 1 2 Microphone Preamplifier Type 2669 Lower Limit Upper Limit 1 Hz bandwidth JA octave A weighted dB Linear 1 lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB gt o a p owe Table 7 5 Dynamic range of the microphone with 1 5 Microphone Preamplifier Type 2669 and Adaptor UC 0211 Maximum Sound Pressure L evel In general the microphone should not be exposed to sound pressure levels which produce voltages higher than the maximum input voltage specified for the connect ed preamplifier After an overload the preamplifier needs time to recover and dur ing this recovery period you cannot measure validly The maximum input voltage for most Bruel amp Kj r preamplifiers is 50V wi
62. relative to the sensitivity with a polar ization voltage of 200V BE1379 12 Falcon Range of Microphone Products 7 23 Microphone Handbook Chapter 7 Low frequency Pressure field b Microphone T ype 4193 Leakage Resistance Response dB 25 2 5 100 1k Hz 10k 100k Frequency Hz 940608e Fig 7 22 Effect of polarization voltage on frequency response The curves show the difference from the response with a polarization voltage of 200V normalised at 250 Hz 7 9 Leakage Resistance To maintain the correct polarization voltage on the microphone the microphone s leakage resistance must be at least 1000 times greater than the supply resistance of the polarization charge even under the most severe environmental conditions This resistance which is generally placed in the preamplifier is typically 10 to 10199 Bruel amp Kj r microphones have a very high leakage resistance which is greater than 5x10 Q at 90 RH and 23 C 7 10 Stability 7 10 1 Mechanical Stability The microphone s design with respect to mechanical stability is improved compared with traditional Bruel amp Kj r microphones The diaphragm clamping ring is less sensitive to accidental force and the protection grid is significantly reinforced Therefore the microphone can withstand mechanical shocks better than
63. s sensitivity or frequency response The microphone has been tested according to IEC 68 2 3 and the effects of humidty on the sensitivity at 250Hz and the frequency response have been found to be less than O 1dB at up to 95 RH non condensing and 40 C 3 26 Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 3 Prepolarized Free field Ton Microphone Type 4189 Effect of Vibration 3 14 Effect of Vibration The effect of vibration is determined mainly by the mass of the diaphragm and is at its maximum for vibrations applied normal to the diaphragm A vibration signal of 1m s RMS normal to the diaphragm typically produces an equivalent Sound Pres sure Level of 62 5dB for a microphone fitted with Protection Grid DB 3420 3 15 Effect of Magnetic Field The effect of a magnetic field is determined by the vector field strength and is normally at its maximum when the field direction is normal to the diaphragm A magnetic field strength of 80A m at 50Hz the test level recommended by IEC and ANSI normal to the diaphragm produces a typical equivalent Sound Pressure Lev el of 6dB Higher frequency components in the microphone output become domi nant at field strengths greater than 500 to 1000 A m 3 16 Electromagnetic Compatibility See Chapter 8 BE1375 12 Falcon Range of Microphone Products 3 27 Microphone Handbook Chapter 3 Prepolarized Free field ip Microphone Type 4189 Spe
64. separated ASCII text files un der the DATA directory SAHHHHHHEBKM Sensitivity calibration 251 2Hz Fries Renee mum NL LLL EN Table 3 1 Calibration data and corrections contained on the data disk Note HHH HEH is the micro phone s serial number a Individual calibration data measured b Low frequency response combined with actuator response and free field corrections c Typical response for Prepolarized Free field 1 2 Microphone Type 4189 d Corrections for Prepolarized Free field 1 2 Microphone Type 4189 These text files can be viewed on Microsoft Windows using the Br el amp Kjaer Microphone Viewer program BK MIC EXE supplied on the disk They can also be accessed by a suitable spreadsheet for further processing or printing 3 4 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 3 Prepolarized Free field oy Microphone Type 4189 Sensitivity Bruel amp Kj r Microphone Viewer must be installed before use see section 1 3 5 3 1 4 Recommended Recalibration Interval With normal handling of the microphone and any associated instrument Bruel amp Kj r recommends that the microphone be recalibrated every 2 years Prepolarized Free field 1 2 Microphone Type 4189 is very stable over this period see section 3 10 to section 3 12 Improper handling is by far the most likely cause of change in the microphone s properties Any damage which causes improper ope
65. under Valid At 23 C 101 325kPa and 50 RH Frequency Responses Two individual frequency responses are shown on the calibration chart Both are normalized to OdB at the reference frequency 251 2 Hz The exact reference frequency is 102 Hz re ISO 266 BE 1375 12 Falcon Range of Microphone Products 3 3 Microphone Handbook Chapter 3 Prepolarized Free field Ap Microphone Type 4189 Introduction The upper curve on the calibration chart is the individual microphone s open circuit 0 incidence free field response This response is the optimized response for Prepo larized Free field 1 2 Microphone Type 4189 The lower curve on the calibration chart is the individual microphone s electrostatic actuator response measured with Electrostatic Actuator UA 0033 This response is used to determine free field responses at angles of incidence other than 0 and responses in other types of sound field The individual microphone s electrostatic actuator response is also available on the data disk The dotted part of the curve is the typical low frequency response Each micro phone s individual lower limiting frequency is measured to ensure that it is within the specified tolerances see Fig 3 3 3 1 3 Data Disk The 34 2 data disk supplied with each microphone supplements the calibration chart It contains individual calibration data and correction curves see Table 3 1 with a frequency resolution of 1 2 octave as comma
66. 0 2dB at 1Hz For applications where the vent is not exposed to the sound field take care to ensure proper static pressure equalization to prevent static displacement of the diaphragm The microphone s low frequency response is common for all types of sound field The microphone s lower limiting frequency 3dB is between 10 and 50mHz with the vent exposed to the sound field If used with Adaptor UC 0211 and 1 2 Micro phone Preamplifier Type 2669 the microphone s lower limiting frequency 3dB is below 0 1Hz with the vent exposed to the sound field The ibdividual microphone s lower limiting frequency 3dB is stated on its calibration chart 7 3 5 Free field Response The microphone s free field correction curves are shown in Fig 7 6 and Fig 7 8 These corrections are added to the microphone s actuator response obtained using Elecrostatic Actuator UA 0033 in order to determine the free field response at any angle of incidence The typical free field response at 0 incidence with and without the protection grid are shown in Fig 7 7 and Fig 7 9 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field lp Microphone Type 4193 Frequency Response Correction dB 15 12 5 0 7 5 2 5
67. 00 C the sensitivity can be permanently changed within the first hour by 0 4dB After this the sensitivity can be permanently changed within the next 10hours by less than 0 4 dB BE1376 12 Falcon Range of Microphone Products 4 21 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Effect of Temperature Note Spedial adaptors inserted between the microphone and preamplifier must be made for high temperature applications in order to protect the preampifier from heat conduction and radiation 4 10 3 Long term Stability Over a period of time the mechanical tension in the diaphragm will decrease due to stretching within the foil This mechanism which in principle causes an increased sensitivity is however very weak for the microphone Measurement of this mecha nism is not possible at room temperature At present no exact value can be given for the microphone s long term stability but measured changes at high temperatures indicate that Free field 1 2 Microphone Type 4190 is more than 10 times more stable than traditional Br el amp Kjaer micro phones This indicates typical changes of less than 1dB in 5000 years 4 11 Effect of Temperature By careful selection of materials optimization of the design and artificial ageing the effect of temperature has been made to be very low The microphone has been designed to operate at temperatures from 30 to 300 C When the microphone is subjected to t
68. 0948e Fig 7 19 Typical equivalent volume real and imaginary parts based on mathematical mode of microphone The Models The following equivalent models are valid at 101 325kPa 23 C and 50 RH Model 1 C 20 062 x 1012 m N L 710kg m R 119 x 106 Ns m where C acoustic diaphragm compliance L acoustic diaphragm mass R acoustic diaphragm damping resistance Model 2 Vig 8 8 mm fo 24kHz Q 0 9 where Vie low frequency volume fg diaphragm resonance frequency Q quality factor BE1379 12 Falcon Range of Microphone Products 7 21 Microphone Handbook Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Capacitance Calibrator Load Volume When the microphone with its protection grid is inserted into the coupler of a calibrator it will load the calibrator by a volume of 190 mm at 250Hz Load volume correction to Pistonphone Type 4228 Calibration Level with Adaptor DP 0776 40 02 dB 7 7 Capacitance Capacitance pF 20 The microphone s impedance is determined by its polarized capacitance In addition the preamplifier s input resistance and capacitance load the microphone This load ing determines the electrical lower limiting frequency and the capacitive input at tenuation However with modern preamplifiers this loading is very small and is induded in the preamplifier gain G see section 7 2 2 Only in special cases with high capacitive loading does the fall i
69. 100 k 200 k Frequency Hz au Fig 8 6 Upper limit of dynamic range 396 distortion of pream plifier with a 50V DC supply voltage due to capaci tive loading as a function of frequency Fig 8 7 shows the distortion limited output for three different voltage supplies in each case when the preamplifier is loaded by the 3m cable normally supplied with the preamplifier 100 30 V 60 V 14 V 28 V 200 1k 10k 100 k 200 k Frequency Hz 940769e Fig 8 7 Maximum output voltage as a function of supply volt age and frequency BE 1380 12 Falcon Range of Microphone Products 8 7 Microphone Handbook Chapter 8 b Microphone Preamplifier Type 2669 Phase Response 8 4 Phase Response 6 0 Degrees 4 0 2 0 0 50 pF 2 0 4 0 6 0 10 100 1k 10k 100 k 200 k Frequency Hz 940771e Fig 8 8 Phase response as a function of input transducer ca pacitance measured with the 3m cable normally sup plied with the preamplifier 8 5 Effect of Temperature As the temperature increases the bias current in the the input amplifier increases This causes the inherent noise to increase and the input impedance to decrease resulting in the e
70. 13 6 5 Dyremie Range cose eee tee xk sari iren SREN REM eN a eS EX MXN EY RS RRERME M M TV RE R VE 6 14 6 6 Equivalent Volume and Calibrator Load Volume sesseeeeeene 6 17 6 7 B er MICRO RM T 6 19 6 8 Polarization euo niid aaie aa a REE a AEREE EE 6 19 6 9 Leakage RSS ISIC earrainean aaa aA Ae AERA SIRENE 6 21 6 10 e E E EA T 6 21 6 11 E fed of Tempera 2p Pe 6 22 6 12 Effect of Ambient PreSSUTe iesms aanaeio aoea eiia EEREN a 6 25 6 13 tj sme dignis 6 27 6 14 SCE OE UENO e 6 27 6 15 Ened OF Magneie Fiel iaronn aa aea aa ag aa 6 27 6 16 Electromagnetic Compati DEY ossai ener nenne te Fn nk deae nean 6 28 6 17 SPECT CATIONS OVE EW E 6 28 6 18 Ordering nformation eeeesssseseeee eene enne nnne nennen nennen 6 28 7 Low frequency Pressure field 1g Microphone Type 4193 7 1 7 1 ADEN enten M 7 2 7 2 en a EE 7 5 7 3 Freuen RESPONSE miniai etn FR ux ne aana dn ping na ain DIR A AEA KEERN 7 7 7 4 Diredtional Charada rec MEE 7 15 25 BEIDE T I ERRORES DL DEI 7 16 7 6 Equivalent Volume and Calibrator Load Volume sesseeeeenene 7 20 7 7 B on acre a A eaa a E a AEAEE EA EAA AAEE 7 22 7 8 Polarization Voltage ran a aar aA AE a REEE EN a R 7 22 7 9 Leakage BeslsEarit8 use een eee pei aaa E en eR EAR pneu a noa aA DERE AAAA REIS MER 7 24 7 10 ciu e e 7 24 7 11 Enego Tenpera E iiaa x
71. 2 Microphone Preamplifier Type 2669 has been developed for making preci sion acoustic measurements with Bruel amp Kjar s wide range of condenser micro phones You can connect 15 microphones directly and 1 14 and lf types using adaptors The preamplifier cable and its connectors all fulfil EMC requirements You can verify the condition of the microphone preamplifier and cable in situ using Bruel amp Kjar s patented Chargeinjection Calibration technique This means that you can detect defects in the entire measurement set up induding the microphone The preamplifier s low output impedance allows long extension cables to be used without problems The robust compact design means that you can use the Jp Microphone Preamplifi er Type 2669 over a wide range of environmental conditions The cable which you can detach from the preamplifier is very thin but strong and remains flexible down to 20 C The 1p Microphone CCLD Preamplifier Type 2671 has been developed for use with prepolarised microphones in mind Full details of the 42 Microphone CCLD Preamplifier Type 2671 are available in the 2671 Product Data Sheet Falcon Range of Microphone Products Bruel amp Kj r Microphone Handbook Chapter 2 Prepolarized Free field 1 2 Microphone Type 4188 BE 1374 12 Falcon Range of Microphone Products 2 1 Microphone Handbook Chapter 2 Prepolarized Free field Ape Microphone Type 4188 Introduction
72. 2 1 Introduction 2 1 1 Description Fig 2 1 Prepolarized Free fidd 1 2 Microphone Type 4188 with Protection Grid DD 0525 included Prepolarized Free field 1 2 Microphone Type 4188 is a prepolarized 1 2 free field microphone and offers some significant advantages when used with portable instru ments For example smaller associated instruments with low power consumption can be used A general advantage is the improved reliability of the associated preamplifier in humid and polluted atmospheres These factors make this prepolar ized condenser microphone particularly suitable for field measurements both out doors and in industrial environments It is suited to IEC 651 Type 1 measurements and when fitted with the supplied Random Incidence Corrector DZ9566 is also suited to ANSI S 1 4 1983 Type 1 measurements The microphone is polarized by a fixed charge carrying layer deposited on the back plate This layer is negatively charged which at low frequencies results in a posi tively increasing output voltage for a positively increasing incident sound pressure As a prepolarized microphone it is externally marked by a pair of grooves This rugged microphone is built to ensure high stability under a variety of condi tions For example the stainless steel alloy diaphragm withstands polluted industri al environments The diaphragm damping ring is firmly secured to ensure the microphones reliability even when the microphone is used witho
73. 21 6 15 Effect of Magnetic Field The effect of a magnetic field is determined by the vector field strength and is normally at its maximum when the field direction is normal to the diaphragm A magnetic field strength of 80A m at 50Hz the test level recommended by IEC and ANSI normal to the diaphragm produces a typical equivalent Sound Pressure Lev el of 16dB Higher frequency components in the microphone output become domi nant at field strengths greater than 500 to 1000 A m BE1378 12 Falcon Range of Microphone Products 6 27 Microphone Handbook Chapter 6 Pressure field ip Microphone Type 4192 Electromagnetic Compatibility 6 16 Electromagnetic Compatibility See Chapter 8 6 17 Specifications Overview OPEN CIRCUIT SENSITIVITY 250 Hz 38dB 1 5dB re 1 V Pa 12 5 mV Pa CALIBRATOR LOAD VOLUME 250 Hz 190 mm POLARIZATION VOLTAGE External 200 V PISTONPHONE TYPE 4228 CORRECTION with DP 0776 40 02 dB FREQUENCY RESPONSE Pressure field response 5Hz to 12 5kHz 1dB 3 15Hz to 20kHz 2dB In accordance with ANSI S1 4 1983 Type 1 and ANSI 81 12 Type M TYPICAL CARTRIDGE THERMAL NOISE 19 0dB A 21 3dB Lin UPPER LIMIT OF DYNAMIC RANGE 3 distortion gt 162dB SPL LOWER LIMITING FREQUENCY 3 dB 1Hz to 2Hz vent exposed to sound MAXIMUM SOUND PRESSURE LEVEL 171dB peak PRESSURE EQUALIZATION VENT Side vented OPERATING TEMPERATURE RANGE 30 to 150 C 22 to 302 F can
74. 26 The typical pressure coefficient at 250Hz for Prepolarized Free field 1 2 Micro phone Type 4188 is 0 021 dB kPa well within the 0 03dB kPa limits required for Type 1 sound level meters by IEC 651 Correction dB 3 40kPa 71 change 2 z 20kPa i change 1 F ZH 10kPa 4 change I 0 LLLI 1 500 1k 10k Frequency Hz 50k 940762e Fig 2 24 Typical variation in frequency response normalized at 250 Hz from that at 101 3kPa as a function of changein ambient pressure BE 1374 12 Falcon Range of Microphone Products 2 25 Microphone Handbook Chapter 2 Prepolarized Free field x Microphone Type 4188 Effect of Humidity Response dB 30 20 TA ue c UE 10 Dag a w 20 500 1k 10k Frequency Hz 50k Fig 2 25 Typical effect of ambient pressure on actuator response a at 101 3kPa b 40kPa change c 80kPa change d at 2kPa Response dB 4 1 10 100 Ambient Pressure kPa 1000 940758e Fig 2 26 Typical variation in sensitivity at 250Hz from that at 101 3kPa as a function of ambient pressure 2 13 Effect of Humidity Due to the microphone s
75. 3 Microphone Handbook Chapter 2 Prepolarized Free field Ape Microphone Type 4188 Effect of Temperature Response dB 1 5 0 5 10 C 0 0 4 50 C 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940772e Fig 2 22 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 2 4 Response dB 1 5 10 C 0 5 0 0 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940806 1e Fig 2 23 Typical variation in 0 incidence freefidd response with Protection Grid DD 0525 normalized at 250Hz as a function of temperature relative to the response at 20 C see Fig 2 7 2 24 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 2 Prepolarized Free field Tor Microphone Type 4188 Effect of Ambient Pressure 2 12 Effect of Ambient Pressure The microphones sensitivity and frequency response are affected by variations in the ambient pressure This is due to changes in air stiffness in the cavity behind the diaphragm and changes in air mass in the small gap between the diaphragm and the back plate The effects are shown in Fig 2 24 to Fig 2
76. 3 pressure field microphone 7 20 Specifications overview 2669 preamplifier 8 11 4188 prepolarized microphone 2 28 4189 prepolarized microphone 3 28 4190 free field microphone 4 28 4191 free field microphone 5 28 4192 pressure field microphone 6 28 4193 pressure field microphone 7 31 Stability long term 4188 prepolarized microphone 2 22 4189 prepolarized microphone 3 22 4190 free field microphone 4 22 4191 free field microphone 5 22 4192 pressure field microphone 6 22 4193 pressure field microphone 7 25 mechanical shock 4188 prepolarized microphone 2 21 4190 free field microphone 4 4 4 7 4189 prepolarized microphone 3 21 4191 free field microphone 5 4 5 7 4190 free field microphone 4 21 4192 pressure field microphone 6 4 6 4191 free field microphone 5 21 7 4192 pressure field microphone 6 21 4193 pressure field microphone 7 4 7 4193 pressure field microphone 7 24 7 Index 6 Falcon Range of Microphone Products Briel amp Kj r Microphone Handbook Index T Temperature 2669 preamplifier 8 8 4188 prepolarized microphone 2 22 4189 prepolarized microphone 3 22 4190 free field microphone 4 22 4191 free field microphone 5 22 4192 pressure field microphone 6 22 4193 pressure field microphone 7 26 Turbulence screen 9 2 V Vibration 4188 prepolarized microphone 2 27 4189 prepolarized microphone 3 27 4190 free field microphone 4 27 4191 free field microphone 5 27 4192 pressure field microph
77. 33 The microphone is polarized by a fixed charge carrying layer deposited on the back plate This layer is negatively charged which at low frequencies results in a posi tively increasing output voltage for a positively increasing incident sound pressure 2 3 4 Low frequency Response The low frequency response see Fig 2 3 is the typical response with the vent ex posed to the sound field If the vent is not exposed to the sound field the sensitivity BE 1374 12 Falcon Range of Microphone Products 2 7 Microphone Handbook Chapter 2 Prepolarized F ree field Ap Microphone Type 4188 Frequency Response increases from OdB at the reference frequency 1000 Hz to approximately 0 6dB at 1Hz For applications where the vent is not exposed to the sound field take care to ensure proper static pressure equalization to prevent static displacement of the diaphragm The microphone s low frequency response is common for all types of sound field The microphone s lower limiting frequency 3dB is between 1 and 5Hz with the vent exposed to the sound field This is measured during production to ensure that specifications are fulfilled 2 3 5 Free field Response The microphone s free field correction curves are shown in Fig 2 6 Fig 2 8 and Fig 2 10 These corrections are added to the microphone s actuator response ob tained using Electrostatic Actuator UA 0033 in order to determine the free field response at any angle of incide
78. 4189 prepolarized microphone 3 19 4190 free field microphone 4 18 4191 free field microphone 5 18 4192 pressure field microphone 6 18 4193 pressure field microphone 7 22 Capacitance 4188 prepolarized microphone 2 20 4189 prepolarized microphone 3 20 4190 free field microphone 4 19 4191 free field microphone 5 19 4192 pressure field microphone 6 19 4193 pressure field microphone 7 22 Charge injection calibration 8 10 CIC 8 10 Connections Preamplifier Type 2669 8 3 D Data disk 4189 prepolarized microphone 3 4 4190 free field microphone 4 4 4191 free field microphone 5 4 4192 pressure field microphone 6 4 4193 pressure field microphone 7 4 Dehumidifier 9 2 Description 4188 prepolarized microphone 2 2 4189 prepolarized microphone 3 2 4190 free field microphone 4 2 4191 free field microphone 5 2 4192 pressure field microphone 6 2 4193 pressure field microphone 7 2 Dimensions Preamplifier Type 2669 8 3 Directional characteristics 4188 prepolarized microphone 2 13 4189 prepolarized microphone 3 14 4190 free field microphone 4 13 4191 free field microphone 5 13 4192 pressure field microphone 6 13 4193 pressure field microphone 7 15 Discolouration 4190 free field microphone 4 22 4191 free field microphone 5 22 4192 pressure field microphone 6 22 4193 pressure field microphone 7 26 Disk data 4189 prepolarized microphone 3 4 4190 free field microphone 4 4 4191 free field microphone 5 4 4192 pres
79. 4190 Equivalent Volume and Calibrator Load Volume Volume mm 60 50 40 30 20 Fig 4 18 Typical equivalent volume real and imaginary parts based on microphone Model 1 C 20 324 x 1012 m5 N L 305kg m R 77x 10 Ns m where C acoustic diaphragm compliance acoustic diaphragm mass R acoustic diaphragm damping resistance Model 2 Vig 46 mm fo 16kHz Q 04 where Vie low frequency volume fg diaphragm resonance frequency Q quality factor Calibrator Load Volume 100k Frequency Hz 9409496 mathematical moda of When the microphone with its protection grid is inserted into the coupler of a calibrator it will load the calibrator by a volume of 250 mm at 250Hz Load volume correction to Pistonphone Type 4228 Calibration Level with Adaptor DP 0776 0 00 dB 4 18 Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 4 Free field 1 5 Microphone Type 4190 Capacitance 4 7 Capacitance Capacitance pF 20 The microphone s impedance is determined by its polarized capacitance In addition the preamplifier s input resistance and capacitance load the microphone This load ing determines the electrical lower limiting frequency and the capacitive input at tenuation However with modern preamplifiers this loading is very small and is i
80. 50 RH Frequency Responses Two typical frequency responses are shown on the calibration chart Both are nor malized to OdB at the reference frequency 1000 Hz The left hand curve on the rear side of the calibration chart is the open circuit 0 incidence free field response for the microphone without the supplied Random Inci dence Corrector DZ 9566 Random incidence response with supplied Random Incidence Corrector DZ 9566 BE1374 12 Falcon Range of Microphone Products 2 3 Microphone Handbook Chapter 2 Prepolarized Free field Ap Microphone Type 4188 Sensitivity The right hand curve on the rear side of the calibration chart is the open circuit random incidence response for the microphone with the supplied Random Incidence Corrector DZ 9566 Each microphone s individual lower limiting frequency is measured to ensure that it is within the specified tolerances see Fig 2 3 2 1 3 Recommended Recalibration Interval With normal handling of the microphone and any associated instrument Bruel amp Kj r recommends that the microphone be recalibrated every 2 years Prepolarized Free field 1 2 Microphone Type 4188 is very stable over this period see section 2 10 to section 2 12 Improper handling is by far the most likely cause of change in the microphone s properties Any damage which causes improper oper ation can probably be detected using a sound level calibrator In many cases the damage can be seen
81. 7 15 The character istics are normalised relative to the 0 response TI A Ill ail WI il Hll ll Jl HI Tl M iil NI TH 15 i NI I il HINT Wn A UIT i at DUAE II i lS 2078 258502 1H Im WI 25 kHz 0 kHz 16 kHz 940852 1e Fig 7 14 Typical directional characteristics of the microphone with Protection Grid DB 3421 WM HALLE NET ff i HM HM OA WTA Wh 2 Mott Tn 151 20 eS H Oe HHS E HEOL HITAN O ls EN A ii 15 01 2038 256 0g gio MIL MA p WA NIIT QUAM t Y AA I IH 25 kHz 20 kHz 940853 1e Fig 7 15 Typical directional characteristics of the microphone without protection grid BE 1379 12 Falcon Range of Microphone Products Microphone Handbook Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Dynamic Range 7 5 Dynamic Range Definition The dynamic range is the range between the upper limit determined by distortion and the inherent noise floor Both limits are influenced by the preamplifier This section gives values for the microphone with and without a preamplifier Inherent Noise The microphone s inherent noise is due to thermal movements of the diaphragm These vary proportionally with the square root of the absolute temperature in K The inherent noise increases with increasing temperature With reference to 20 C the inherent noise changes
82. 8 3 Typical frequency response as a function of input transducer capacitance at low frequen Gies and as a function of capacitive loading at high frequencies The low frequency curves in Fig 8 3 show the low frequency response of the pream plifier for various capacitances typical of 1 1 2 and 1 4 microphones Note they do not show the lower cut off frequencies of the microphones The effects of various capacitive output loads cables etc on the high frequencies are also shown All curves shown in Fig 8 3 apply only for low signal levels where the limitations shown in Fig 8 5 and Fig 8 6 have no influence 8 4 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 8 ip Microphone Preamplifier Type 2669 Dynamic Range 8 3 Dynamic Range Overview Lower limit with 15 pF Upper limit 60 V microphone uV supply f 10 kHz Dynamic Range dH A weighted 2 2 147 Lin 20 Hz to 300 kHz d i 134 Table 8 2 Nominal open circuit sensitivity a See Fig 8 6 for upper limit at higher frequencies Inherent Noise Noise re 1 uV dB Frequency Hz 940882e Fig 8 4 Typical y 3 octave band inherent noise spectrum measured with a 15pF dummy micro phone The shaded bar graph is the broad band 20Hz to 20kHz noiselevel and the white bar graph the A weghted noise leva The circles repr
83. 9 Specifications Overview 8 9 Specifications Overview FREQUENCY RESPONSE re 1 kHz 3Hz to 200kHz 0 5dB ATTENUATION 0 25 dB typical PHASE LINEARITY t3 at 20Hz to 100 kHz PHASE MATCHING 0 3 at 50Hz INPUT IMPEDANCE 15 GQ 0 45 pF OUTPUT IMPEDANCE 252 MAX OUTPUT CURRENT 20 mA peak Note The max output current can be limited by the power supply MAX OUTPUT VOLTAGE Total supply voltage 10 V Vpeak peak OUTPUT SLEW RATE 2V us DISTORTION THD Less than 80 dB at 25V out 1 kHz NOISE 15pF DUMMY lt 10 0uV Lin 20 Hz 300 kHz lt 2 2uV A weighted POWER SUPPLY DUAL 14V to t60V POWER SUPPLY SINGLE 28V to 120V OUTPUT DC OFFSET 1V for a dual supply or 1 2 the voltage of a single supply CURRENT CONSUMPTION 3mA plus output current CALIBRATION INPUT Charge insert capacity typically 0 2 pF Max 10 Vaws input impedance 1 nF ENVIRONMENTAL Conforms to EMC requirements EN50081 1 and prEN50081 2 when connected to an in strument that also conforms to these regulations Note the above are valid for a 15pF mic 1 2 and a 3 metre cable CONNECTOR TYPE LEMO type FGJ OB 307 at preamplifier LEMO type FGG 1B 307 2669L or Br el amp Kj r JP 0715 2669 B to measuring device PIN CONNECTIONS Cable s output plug seen from outside 940478 1e DIMENSIONS 212 7 mm x 110 mm including connector 8 10 Ordering Information Extension Cabl
84. 940756e Fig 5 27 Typical effect of ambient pressure on actuator response a at 101 3kPa b 40kPa change c 80kPa change d at 2kPa Falcon Range of Microphone Products Br el amp Kjaer 5 26 Microphone Handbook Chapter 5 Free field lp Microphone Type 4191 Effect of Humidity Response dB 4 10 100 Ambient Pressure kPa 1000 9407606 Fig 5 28 Typical variation in sensitivity at 250Hz from that at 101 3kPa as a function of ambient pressure 5 13 Effect of Humidity Due to the microphone s high leakage resistance humidity has in general no effect on the microphone s sensitivity or frequency response The microphone has been tested according to IEC 68 2 3 and the effects of humidty on the sensitivity at 250Hz and the frequency response have been found to be less than O 1dB at up to 95 RH non condensing and 40 C 5 14 Effect of Vibration The effect of vibration is determined mainly by the mass of the diaphragm and is at its maximum for vibrations applied normal to the diaphragm A vibration signal of 1m s RMS normal to the diaphragm typically produces an equivalent Sound Pres sure Level of 65 5dB for a microphone fitted with Protection Grid DB 3421 5 15 Effect of Magnetic Field The effect of a magnetic field is determined by the vector field strength and is normally at its maximum when the field
85. B 15 10 m 7 5 2 5 we A 609 90 id 180 Random 150 120 500 1k 10k Frequency Hz 50k 940803 1e Fig 3 8 Freefidd correction curves for the microphone without protection grid Response dB 5 dB 0 100 1k 10k 100 k Frequency Hz 940887e Fig 3 9 Typical free field response 0 incidence for the microphone without protection grid BE 1375 12 Falcon Range of Microphone Products 3 11 Microphone Handbook Chapter 3 Prepolarized Free field Ap Microphone Type 4189 Frequency Response 3 3 6 Random incidence Response A microphone s response in a diffuse sound field is equivalent to its random inci dence response The microphone s random inci dence correction curves are shown in Fig 3 6 and Fig 3 8 These corrections are added to the microphone s actuator re Sponse obtained using Electrostatic Actuator UA 0033 in order to determine the random incidence response The typical random incidence response with and with out the protection grid are shown in Fig 3 10 and Fig 3 11 The random incidence corrections are calculated
86. B Capacitance 14 1 pF Valid At Temperature 23 2 Ambient Static Pressure 101 3 kPa n Actuator Re Relative Humidity 50 ceo Frequency 250 Hz Polarization Voltage external 0v Sensitivity Traceable To DPLA Danish Primary Laboratory of Acoustics L LH NIST National Institute of Standards and Technology USA l HH l i IEC 1094 4 Type WS 2 F Sound Incidence Environment Calibration Conditions D i 35 101 5 kPa 20 C 55 RH Procedure 704215 Date 21 Apr 1994 Signature Ko 26 S Example Ko 26 26 2 0 2 dB BC 0224 12 2 5 10 20 50 100 200 10k See the microphone handbook for further information Frequency Hz Fig 3 2 Microphone calibration chart Open circuit Sensitivity The stated open circuit sensitivity is valid at the reference frequency 251 2 Hz for free field random incidence and pressure field conditions The stated uncertainty is the Us value the value valid for 95 confidence level Ambient Conditions The ambient conditions are measured continuously during calibration at the factory The calibration results obtained at the measured Environmental Calibration Condi tions are corrected to the reference ambient conditions stated
87. E supplied on the disk They can also be accessed by a suitable spreadsheet for further processing or printing Bruel amp Kj r Microphone Viewer must be installed before use see section 1 3 5 4 4 Falcon Range of Microphone Products Briel amp Kj r Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Sensitivity 4 1 4 Recommended Recalibration Interval With normal handling of the microphone and any associated instrument Bruel amp Kj r recommends that the microphone be recalibrated every 2 years Free field 1 2 Microphone Type 4190 is very stable over this period see section 4 10 to section 4 12 Improper handling is by far the most likely cause of change in the microphone s properties Any damage which causes improper operation can probably be detected using a sound level calibrator In many cases the damage can be seen by carefully inspecting the protection grid and diaphragm 4 2 Sensitivity 4 2 1 Open circuit Sensitivity The open circuit sensitivity is defined as the sensitivity of the microphone when not loaded by the input impedance of the connected preamplifier the termination is described in IEC 1094 2 The sensitivity is measured for the individual microphone at 251 2Hz and stated on the microphone s calibration chart see section 4 1 2 and data disk see section 4 1 3 The nominal sensitivity is shown in Table 4 1 Nominal open circuit sensitivity Accepted Deviation dB
88. H 2 11 Effect of Temperature By careful selection of materials optimization of the design and artificial ageing the effect of temperature has been made to be very low The microphone has been designed to operate at temperatures from 30 to 125 C 70 C with Random Incidence Corrector DZ9566 See section 2 10 2 for permanent changes in sensitivity at temperatures at 125 C Falcon Range of Microphone Products Bruel amp Kj r Microphone Handbook Chapter 2 Prepolarized Free field 271 Microphone Type 4188 Effect of Temperature The reversible changes are shown in Fig 2 21 as a change in sensitivity and in Fig 2 22 and Fig 2 23 as changes in the frequency response normalized at 250 Hz Response dB p dB J5 00 Dd 0 5 2 0 2 5 50 0 50 100 150 200 250 300 Temperature C 940873e Fig 2 21 Typical variation in sensitivity at 250Hz as a function of temperature relative to the sensitivity at 20 C Temperature Coefficient 1000 H2 0 005 dB C typical for the range 10 to 50 C The effect of temperature on the free field response see Fig 2 23 of the microphone is the sum of the following effects e the calculated effect of the change in the speed of sound due to temperature on the 0 incidence free field correction e the measured change in the actuator response due to temperature see Fig 2 22 BE 1374 12 Falcon Range of Microphone Products 2 2
89. NG TEMPERATURE RANGE 30 to 150 C 22 to 302 F can be used up to 300 C 572 F but with a permanent sensitivity change of typically 0 4 dB which stabilises after one hour OPERATING HUMIDITY RANGE 0 to 100 RH without condensation STORAGE TEMPERATURE 30 to 70 C 22 to 158 F TEMPERATURE COEFFICIENT 250 Hz 0 002dB C typical for the range 10 to 50 C 5 18 Ordering Information Preamplifier Type 2669 1 Microphone Preamplifier Calibration Equipment Type 4231 Sound Level Calibrator Type 4226 Multifunction Acoustic Calibrator Type 4228 Pistonphone PRESSURE COEFFICIENT 250 Hz 0 007 dB kPa typical INFLUENCE OF HUMIDITY 0 1 dB 100 RH VIBRATION SENSITIVITY 1000 Hz Typically 65 5 dB equivalent SPL for 1 m s axial acceleration MAGNETIC FIELD SENSITIVITY Typically 16 dB SPL for 80 A m 50Hz field ESTIMATED LONG TERM STABILITY gt 1 000 years dB at 20 C gt 1 00 hours dB at 150 C DIMENSIONS Diameter 13 2 mm 0 52in with grid 12 7 mm 0 50 in without grid 13 5 mm 0 54 in with grid 12 6 mm 0 50 in without grid Thread for preamplifier mounting 11 7 mm 60 UNS Height The data above are valid at 23 C 101 3 kPa and 5096 RH unless otherwise specified UA 0033 Electrostatic Actuator Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 5 Free field 1p Microphone Type 4191 Orde
90. Preamplifier Type 2669 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 4 Free field 1 2 Microphone Type 4190 Introduction 4 1 2 The Calibration Chart Each microphone is supplied with an individual calibration chart see Fig 4 2 which gives the microphone s open circuit sensitivity polarized capacitance and free field and actuator frequency responses Free field 1 2 Microphone Type 41 90 Typical Response Free fiel e 0 Sound Incidence Bruel amp Kj r Calibration Chart LLLI Serial No 419011A Open circuit Sensitivity So 26 4 dB re 1V Pa Equivalent to 47 7 mV Pa Uncertainty 95 confidence level 0 2 dB Capacitance 16 4 pF ER Valid At Temperature 23 j Ambient Static Pressure 101 3 kPa EB MT Actuator Re Relative Humidity 50 EN Frequency 250 Hz Polarization Voltage external 200 V Sensitivity Traceable To DPLA Danish Primary Laboratory of Acoustics NIST National Institute of Standards and Technology USA IEC 1094 4 Type WS 2 F Sound Incidence Environmental Calibration Conditions TDIr m t ze 100 1 kPa 25 C 35 RH Procedure 704216 Date 21 Apr 1994 Signature Ko 26 S Example Ko 26 26 2 0 2 dB BC 0225 12
91. SPL 63 5 dB 62 5dB 62 5 dB 65 5dB 65 5dB 65 5 dB with axial 1 m s Effect of Magnetic Field 50 Hz field Table 1 2 Comparision of main specifications for the different microphones in the Falcon Range BE 1372 12 Falcon Range of Microphone Products 1 5 Microphone Handbook Chapter 1 Introduction The Microphones 1 3 3 Physical Dimensions Type 4188 Type 4189 Type 4190 Type 4191 Type 4192 Type 4193 Microphone Length with 9 17 6 f 13 5 grid Housing Length with 16 3 16 3 12 6 12 6 out grid Housing Diameter 12 7 0 03 mm Housing Front end 6 2 6 2 6 1 6 1 6 1 Length Ring Diameter Depth to Cen tre Terminal Preamplifer Thread 60 UNS 2 Preamplifer Thread Length Protection Grid Thread 12 7 gt 12 7 60 UNS 2 Protection Grid Diameter 13 2 13 2 13 2 13 2 13 2 0 02 mm Table 1 3 Dimensions of the different microphones in the Falcon Range 1 3 4 Calibration For general routine calibration you can check the sensitivity at 1kHz with Sound Level Calibrator Type 4231 or at 250Hz with Pistonphone Type 4228 For a thor ough calibration Multifunction Acoustic Calibrator Type 4226 allows you to meas ure both sensitivity and frequency response An in situ check which also takes the state of the microphone into account is Bruel amp Kjaer s Charge Injection Calibration technique which is a patented feature of 12 Microphone Preamplifier Type 2669 see Chapter 8 1 6 Falcon
92. T lll RN 25 KH 6 3 kHz z YL Ves yy 10 kHz 9 eds 12 5 kHz HUNT TTT NW T ll 940788e Fig 4 14 Typical directional characteristics of the microphone with Protection Grid DB 3420 BE 1376 12 Falcon Range of Microphone Products 4 13 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Dynamic Range Z HIT WM WI PU UT MIU HIT T E Ih hos Hl WN ma i 20 8 258108 H S I Iba STITT A M Wisc PA BATE AM A il T i III Ji THAT TIT tT j il Hl TT 1 Ji UN AT Wi MALUM TA KH TIR 7 7 I 8 kHz E A 20 kHz SS 9 III 6 3 kHz SSS 940790e Fig 4 15 Typical directional characteristics of the microphone without protection grid 45 Dynamic Range Definition The dynamic range is the range between the upper limit determined by distortion and the inherent noise floor Both limits are influenced by the preamplifier This section gives values for the microphone with and without a preamplifier Inherent Noise The microphone s inherent noise is due to thermal movements of the diaphragm These vary proportionally with the square root of the absolute temperature in K The inherent noise increases with increasing temperature With reference to 20 C the inherent noise changes by 0 5dB at 55 C and by 0 5dB at 12 C The maximum variation of this noise for different samples of Free field 1 2 Microphone Type 4190
93. Technical Documentation Microphone Handbook For the Falcon Range of Microphone Products Bruel amp Kj r WORLD HEADQUARTERS DK 2850 N rum Denmark Telephone 4542800500 Telex 37316 bruka dk Fax 44542801405 e mail info bk dk Internet http www bk dk BA 5105 12 Microphone H andbook Revision February 1995 Br el amp Kj r Falcon Range of Microphone Products BA 5105 12 Microphone Handbook Trademarks Microsoft is a registered trademark and Windows is a trademark of Microsoft Cor poration Copyright 1994 1995 Bruel amp Kj r A S All rights reserved No part of this publication may be reproduced or distributed in any form or by any means without prior consent in writing from Br el amp Kjaer A S Naerum Denmark 0 2 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Contents l Introduction eeeseeeeeteettnntetttnnttttnnttttntettt ntes 11 1 1 About the Microphone Handbook edere ceterae tnnt EERE 1 2 1 2 About the Falcon Range of Microphone Products eese 1 2 1 3 The ETOCS Em 1 2 1 4 A heres T DB csse eren aE e e YA ERN E nae Rr X ERE VR RR EK V STU T cR ETE 1 8 2 Prepolarized Free field ipu Microphone Type 4188 2 3 24d ipd Wo ECC 2 2 22 S tl EE 2 4 2 3 FPOQUSICY RBS DON T 2 5 2 4 CSCC eal ETA iidem 2 13 2 5 BID e n 2 16 2 6 Equi
94. Visual Basic pro grams and can also be used by other programs About Bruel amp Kj r Microphone Viewer Br el amp Kjar Microphone Viewer shows the individual microphone s data supplied on the data disk in either graphical or tabular form BE 1372 12 Falcon Range of Microphone Products 1 7 Microphone Handbook Chapter 1 Introduction The Preamplifiers When the program is started from Windows the calibration data in the DATA directory of the disk in the A drive is shown If no data is found the Open box automatically appears Select the Sensitivity file to access all data associated with the microphone Selecting a Result or Work file will only give you access to that particular response The data can be copied to the hard disk using the Copy Microphone Data function in the File menu Individual data files are named with the microphones serial number to prevent file name conflicts with data files from other microphones The data shown can also be printed out or copied to the dipboard for further processing in spreadsheets and text editors When a Sensitivity file is selected all frequency responses are obtained by adding the relevant corrections and the low frequency response to the actuator response Any additional information about Bruel amp Kj r Microphone Viewer can be seen in the README TXT file In addition help in the form of hypertext is induded throughout to guide you 1 4 The Preamplifiers The 1
95. a gh Ewan ac nk EV RR REF V Ten NEE 7 26 212 Efed OF Ambient PEeSSHEB sio eere tenet ra Sere tr e ERR RR X P REFER a 7 28 313 PC OF APUG oc vscces caaacecicassesavelss veadaeedenssnescnvacsieiawas E E 7 30 7 14 TOC OF VID SUOD ceste re n a E N REE E E 7 30 2415 ECE OP Magnetic d lm 7 30 7 16 Electromagnetic ConmpalLibillEy cetero ue a enirn tri rn nien nain 7 31 7 17 Specifications Overview eeessssseeeeeeee eene nennen nnne nn nnne nnns 7 31 7 18 Ordering PPO zio iieiaei aaia aaa paN Eei 7 32 BE 1373 12 Falcon Range of Microphone Products 0 5 Microphone Handbook Contents 8 ip Microphone Preamplifier Type 2669 8 1 8 1 ipo IW RI 8 2 8 2 gs amico MEE 8 4 8 3 BAUR SS ESI CRTPTRREETDTRDIDICO TRO 0D E a DERE 8 5 8 4 Phase PRS E E T PER FRE nene N ER deiutusedenuyy Gd ERE R UR MPa NER E 8 8 8 5 aur Tempa ie Em 8 8 8 6 Emet Oh Oa con SF i em 8 9 8 7 Electromagnetic Compatibility EMC ieira aai anaa 8 9 8 8 Bruel amp Kjaer s Patented Charge injection Calibration Technique 8 10 8 9 PSC ITCH ORS CMGI E 8 11 8 10 Ordering EPONA ON Tm 8 11 B 50 oo o T 9 1 9 1 PE f or 9 2 Index 0 6 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 1 ntroduction BE 1372 12 Falcon Range of Microphone Products Microphone Handbook Chapter 1
96. a well defined volume 3 10 2 High temperature Stability The diaphragm is made of a stainless steel alloy The alloy has been carefully selected and is very resistant to heat This means that the diaphragm tension and therefore the sensitivity remain the same even after several hours operation at high temperature The microphone has been tested at temperatures up to 150 C Below 150 C no changes occur At 150 C the sensitivity can be permanently changed within the first hour by less than 0 05dB After this the sensitivity can be permanently BE1375 12 Falcon Range of Microphone Products 3 21 Microphone Handbook Chapter 3 Prepolarized Free field Ap Microphone Type 4189 Effect of Temperature changed within the next 10hours by a similar value These changes are due to decreasing charge of the electret Note special adaptors inserted between the microphone and preamplifier must be made for high temperature applications in order to protect the preampifier from heat conduction and radiation 3 10 3 Long term Stability The microphone s long term stability is determined by the stability of the electret charge The charge decays very slowly even in humid conditions See Br el amp Kjaer Technical Review no 4 1979 and the spedifications given below 71000 years dB dry air at 20 C 22 hours dB dry air at 150 C gt 40 years dB air at 20 C 90 RH gt 1 year dB air at 50 C 9096RH 3 11 Effect of Temp
97. agm in terms of a complex equivalent volume This makes it easier to evaluate the effect of microphone loading on closed cavities or acoustic calibration couplers The real and imaginary parts of the equivalent volume shown in Fig 6 18 are in parallel They are calculated from a simple R L C series model of the microphone which gives the best overall approximation of the microphone s diaphragm imped ance The Models The following equivalent models are valid at 101 325 kPa 23 C and 50 RH BE 1378 12 Falcon Range of Microphone Products 6 17 Microphone Handbook Chapter 6 Pressure field lp Microphone Type 4192 Equivalent Volume and Calibrator Load Volume Volume mm 12 10 8 1k 10k 100k 100 3 Frequency Hz 00 940948e Fig 6 18 Typical equivalent volume real and imaginary parts based on mathematical mode of microphone Model 1 C 20 062 x 1012 m N 710kg m R 2119 x 10 Ns n where C acoustic diaphragm compliance L acoustic diaphragm mass R acoustic diaphragm damping resistance Model 2 Vig 8 8 mm fo 24kHz Q 09 where Vic low frequency volume fg diaphragm resonance frequency Q quality factor Calibrator Load Volume When the microphone with its protection grid is inserted into the coupler of a calibrator it will load the calibrator by a volume of 190 mm at 250Hz Load vol
98. ance which is a reliable indicator of the microphone s condition Housing cable Calibration Signal Source Insert voltage Cn Cm Ci Typical Values C 15 20 pF Cj 0 3 pF C 0 2 pF A 1 940528e Fig 8 11 Charge injection calibration CIC technique compared to insert voltage calibration technique The technique works by introducing a small but accurately defined capacitance c typically 0 2pF with a very high leakage resistance greater than 50000 GQ into the circuit of the preamplifier see Fig 8 11 upper diagram C and Rj represent the preamplifier s high input impedance and A its gain 1 For a given calibration signal Vi the output Vo of this arrangement will change measurably even for small changes in the microphone s capacitance Cm The CIC technique is about 100 times more sensitive than the insert voltage calibration ar rangement shown in Fig 8 11 lower diagram In the extreme case where there is significant leakage between the microphone s diaphragm and its backplate Cm becomes very large the signal output will change by tens of decibels compared with only tenths of a decibel using the insert voltage method Another important CIC feature is that unlike the insert voltage technique it is far less sensitive to external electrical fields 8 10 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 8 ion Microphone Preamplifier Type 266
99. and Fig 3 8 These corrections are added to the microphone s actuator response obtained using Elecrostatic Actuator UA 0033 in order to determine the free field response at any angle of incidence The typical free field response at 0 incidence with and without the protection grid are shown in Fig 3 7 and Fig 3 9 BE1375 12 Falcon Range of Microphone Products 3 9 Microphone Handbook Chapter 3 Prepolarized Free field Ty Microphone Type 4189 Frequency Response Correctionn dB 15 12 5 0 10 7 5 60 2 5 L Random 0 I 180 90 120 2 5 150 B lli F 7 5 10 500 1k 10k Frequency Hz 50k 940804 1e Fig 3 6 Freefidd correction curves for the microphone with Pro tection Grid DB 3420 Response dB 5 100 1k 10k 100k Frequency Hz 940886e Fig 3 7 Typical freefidd response 0 incidence for the microphone with Protection Grid DB 3420 3 10 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 3 Prepolarized Free field ty Microphone Type 4189 Frequency Response Correction d
100. arge Therefore when mounting the microphone on a preamplifier the housings of the microphone and preamplifier must be connected before the centre pins make contact The de signs of Br el amp Kj r preamplifiers and sound level meters ensure this 3 9 Leakage Resistance The microphone s leakage resistance is greater than 5x 103 Q at 90 RH and 23 C 3 10 Stability 3 10 1 Mechanical Stability The microphone s design with respect to mechanical stability is improved compared with traditional Bruel amp Kjar microphones The diaphragm damping ring is less sensitive to accidental force and the protection grid is significantly reinforced Therefore the microphone can withstand mechanical shocks better than traditional Bruel amp Kj r microphones The sensitivity change of the microphone is less than 0 1dB after a free fall of 1m onto a solid hardwood block re IEC 68 2 32 This improved mechanical stability makes Prepolarized Free field 1 2 Microphone Type 4189 well suited for surface mounting and for mounting in small couplers as no mechanical adaptor is required to protect the diaphragm damping ring The microphone can be supported by the diaphragm damping ring directly on the cou pler s surface Any force of less than 5 Newtons will cause a change in sensitivity of less than 0 005dB This makes the microphone well suited for fitting in small plane wave couplers used for reciprocity calibration and any other small coupler with
101. arized Free field 1 2 Microphone Type 4189 at a Peak level of 154dB re 20uPa The microphone s distortion increases smoothly as a function of sound pressure level until the diaphragm s displacement becomes so large that it hits the back plate When this occurs at a Peak level of 158dB the output voltage is dipped We recommend not to expose Prepolarized Free field 1 2 Microphone Type 4189 to levels higher than 158dB Peak 3 6 Equivalent Volume and Calibrator Load Volume Equivalent Volume For some applications it is practical to express the acoustic impedance of the micro phone diaphragm in terms of a complex equivalent volume This makes it easier to evaluate the effect of microphone loading on closed cavities or acoustic calibration couplers The real and imaginary parts of the equivalent volume shown in Fig 3 18 are in parallel They are calculated from a simple R L C series model of the microphone which gives the best overall approximation of the microphone s diaphragm imped ance The Models The following equivalent models are valid at 101 325 kPa 23 C and 50 RH 3 18 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 3 Prepolarized Free field 1p Microphone Type 4189 Equivalent Volume and Calibrator Load Volume Volume mm 60 50 40 30 20 100 1k 10k 100k Fre
102. ast 1000 times greater than the supply resistance of the polarization charge even under the most severe environmental conditions This resistance which is generally placed in the preamplifier is typically 10 to 1019 o Bruel amp Kj r microphones have a very high leakage resistance which is greater than 5x 10 o at 90 RH and 23 C 6 10 Stability 6 10 1 Mechanical Stability The microphone s design with respect to mechanical stability is improved compared with traditional Bruel amp Kjar microphones The diaphragm damping ring is less sensitive to accidental force and the protection grid is significantly reinforced Therefore the microphone can withstand mechanical shocks better than traditional Bruel amp Kj r microphones The sensitivity change of the microphone is less than 0 1dB after a free fall of 1m onto a solid hardwood block re IEC 68 2 32 This improved mechanical stability makes Pressure field 1 2 Microphone Type 4192 well suited for surface mounting and for mounting in small couplers as no mechani cal adaptor is required to protect the diaphragm damping ring The microphone can be supported by the diaphragm damping ring directly on the coupler s surface Any force of less than 5Newtons will cause a change in sensitivity of less than 0 005 dB This makes the microphone well suited for fitting in small plane wave couplers used for reciprocity calibration and any other small coupler with a well defined volume 6 10 2 Hig
103. at 90 RH and 23 C 5 10 Stability 5 10 1 Mechanical Stability The microphone s design with respect to mechanical stability is improved compared with traditional Bruel amp Kjar microphones The diaphragm damping ring is less sensitive to accidental force and the protection grid is significantly reinforced Therefore the microphone can withstand mechanical shocks better than traditional Bruel amp Kj r microphones The sensitivity change of the microphone is less than O 1dB after a free fall of 1m onto a solid hardwood block re IEC 68 2 32 This improved mechanical stability makes Free field 1 2 Microphone Type 4191 well suited for surface mounting and for mounting in small couplers as no mechani cal adaptor is required to protect the diaphragm clamping ring The microphone can be supported by the diaphragm damping ring directly on the coupler s surface Any force of less than 5Newtons will cause a change in sensitivity of less than 0 005 dB This makes the microphone well suited for fitting in small plane wave couplers used for reciprocity calibration and any other small coupler with a well defined volume 5 10 2 High temperature Stability The diaphragm is made of a stainless steel alloy The alloy has been carefully selected and is very resistant to heat This means that the diaphragm tension and therefore the sensitivity remain the same even after several hours operation at high temperature The microphone has been tested
104. ator response obtained using Electrostatic Actuator UA 0033 This is a reproducible and practical method for calibrating a microphone s frequency response BE 1376 12 Falcon Range of Microphone Products 4 7 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Frequency Response Response dB 5 20 100 1k 10k 100k Frequency Hz 9406706 Fig 4 4 Typical actuator response magnitude measured with Electrostatic Actuator UA 0033 Response Degrees 0 135 180 100 1k 10k 100 k Frequency Hz 9406716 Fig 4 5 Typical actuator response phase measured with Electrostatic Actuator UA 0033 If the polarization voltage is positive as it is with Bruel amp Kj r instruments the output voltage is negative for a positive pressure applied to the diaphragm 4 3 4 Low frequency Response The low frequency response see Fig 4 3 is the typical response with the vent ex posed to the sound field If the vent is not exposed to the sound field the sensitivity increases from OdB at the reference frequency 251 2 Hz to approximately 0 3dB at 1Hz 4 8 Falcon Range of Microphone Products Briel amp Kj r Microphone Handbook Chapter 4 Free
105. by carefully inspecting the protection grid and diaphragm 2 2 Sensitivity 2 2 1 Open circuit Sensitivity The open circuit sensitivity is defined as the sensitivity of the microphone when not loaded by the input impedance of the connected preamplifier the termination is described in IEC 1094 2 The sensitivity is measured for the individual microphone at 1000 Hz and stated on the microphone s calibration chart see section 2 1 2 The nominal sensitivity is shown in Table 2 1 Nominal open circuit sensitivity Accepted Deviation dB Table 2 1 Nominal open circuit sensitivity 2 2 2 Loaded Sensitivity When loaded by a preamplifier the sensitivity of the microphone is given by where Sc overall sensitivity of microphone and preamplifier combination So open circuit sensitivity of microphone G voltage gain of microphone and preamplifier combination in dB 2 4 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 2 Prepolarized Free field 1p Microphone Type 4188 Frequency Response With Microphone Preamplifier Type 2639 G 0 15dB With 1 2 Microphone Preamplifier Type 2669 G 0 30 dB Example Loaded sensitivity of typical microphone with 1 2 Microphone Preamplifier Type 2669 Sc 29 8 0 30 30 1 dB 2 2 3 K factor Some types of Br el amp Kj r instruments use the K factor correction factor or the Ko factor open circuit correction factor for calibration
106. can be replaced by microphones from the Falcon Range Table 1 1 Replacement of traditional Bruel amp Kjar microphones with ones from the Falcon Range Microphone Specifications The design and construction of each microphone results in a reliable transducer of high sensitivity and low temperature dependence Most of the data given for the microphones in this handbook are for open circuit conditions which means that the microphone looks into an infinitely high impedance Table 1 2 summarises the most important specifications for the microphones in the Falcon Range In practice however a microphone is used with a preamplifier which slightly influences the given responses When you use a Br el amp Kjae preamplifier for example 42 Micro phone Preamplifier Type 2669 the input impedance is very high high resistance low capacitance and the loading on the microphone cartridge is insignificant Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 1 Introduction The Microphones Specification Type 4188 Type 4189 Type 4190 Type 4191 Type 4192 Type 4193 XT Prepolarized Free Prepolarized Free Low Noise nirasound Nominal Open circuit 31 6 mV Pa 50 mV Pa 50 mV Pa 12 5 mV Pa 12 5 mV Pa 12 5 mV Pa Sensitivity Polarization Voltage 1 qB 1 dB 1 dB px NN i a 12 5 Hz to 8kHz 10Hz to 8kHz Hz to 10kHz 5Hz to 16 kHz 5Hz to 12 5kHz 0 12Hz to12 5 kHz t2dB t2dB t2dB t2dB t2dB t2
107. capacitance In addition the preamplifier s input resistance and capacitance load the microphone This load ing determines the electrical lower limiting frequency and the capacitive input at tenuation However with modern preamplifiers this loading is very small and is induded in the preamplifier gain G see section 5 2 2 Only in special cases with high capacitive loading does the fall in capacitance with frequency have to be taken into account 250V 200 V 150 V 28 V 100 1k Hz 10k 100k Frequency Hz 940604e Fig 5 19 Variation of capacitance with polarization voltage and frequency Typical capacitance at 250Hz 18 pF The capacitance is individually calibrated and stated on the calibration chart 5 8 Polarization Voltage Generally a microphone is operated at its nominal polarization voltage For Free field 1 2 Microphone Type 4191 this is 200V As this polarization voltage is posi tive the output voltage is negative for a positive pressure applied to the dia phragm In special cases where there is a risk of preamplifer overload or there are long cables to be driven choose a lower voltage This will cause a lower sensitivity see Fig 5 20 and a change in the frequency response see Fig 5 21 BE 1377 12 Falcon Range of Microphone Products 5 19 Microphone Ha
108. ce of the microphone for 1 2 Microphone Preamplifier Type 2669 see Fig 3 16 and Chapter 8 Sound Pressure Level 20 re 20 uPa dB L 15 E A A L 10 5 Microphone and Preamplifier 0 Combination 5 m PL Preamplifier Microphone a wom 10 10 100 1k 10k 20k M P C Frequency Hz 940717e Fig 3 16 Y 3 octave band inherent noise spectrum The shaded bar graphs are the broad band 20Hz to 20 kHz noise levds and the white bar graphs the A weghted noise Ieas of the microphone M 1 Microphone Preamplifier Type 2669 P and microphone and pream plifier combination C 3 16 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 3 Prepolarized Free field Microphone Type 4189 Dynamic Range Distortion The distortion is determined mainly by the microphone but at the highest opera tion levels the preamplifier also contributes to the distortion see Fig 3 17 Distortion 96 10 pnd Harmonic gid Harmonic 0 01 125 135 145 SPL dB 155 940501e Fig 3 17 Typical distortion characteristics of Prepolarized Free fidd 1 2 Microphone Type 4189 The distortion is dependent on the capacitance parallel to the microphone It in creases with increasing capacitance The
109. cifications Overview 3 17 Specifications Overview OPEN CIRCUIT SENSITIVITY 250 Hz 26dB 1 5dB re 1 V Pa 50mV Pa POLARIZATION VOLTAGE External 0 V FREQUENCY RESPONSE 0 incidence free field response 10 Hz to 8kHz 1 dB 6 3 Hz to 20kHz 2dB In accordance with IEC 651 Type 1 LOWER LIMITING FREQUENCY 3 dB 2Hz to 4Hz vent exposed to sound PRESSURE EQUALIZATION VENT Rear vented DIAPHRAGM RESONANCE FREQUENCY 14 kHz typical 90 phase shift CAPACITANCE POLARIZED 14 pF typical at 250 Hz EQUIVALENT AIR VOLUME 101 3 kPa 46 mm ndividually calibrated CALIBRATOR LOAD VOLUME 250 Hz 260 mm PISTONPHONE TYPE 4228 CORRECTION with DP 0776 0 00 dB TYPICAL CARTRIDGE THERMAL NOISE 14 6dB A 15 3dB Lin UPPER LIMIT OF DYNAMIC RANGE 3 distortion gt 146dB SPL MAXIMUM SOUND PRESSURE LEVEL 158 dB peak OPERATING TEMPERATURE RANGE 30 to 150 C 22 to 302 F OPERATING HUMIDITY RANGE 0 to 100 RH without condensation STORAGE TEMPERATURE 30 to 70 C 22 to 158 F TEMPERATURE COEFFICIENT 250 Hz 0 001 dB C typical for the range 10 to 50 C PRESSURE COEFFICIENT 250 Hz 0 010 dB kPa typical 3 18 Ordering Information Preamplifier Type 2669 1 Microphone Preamplifier Type 2671 1 Microphone Preamplifier Calibration Equipment Type 4231 Sound Level Calibrator Type 4226 Multifunction Acoustic Calibrat
110. cts Microphone Handbook Br el amp Kj r Chapter 6 Pressure field 1 Microphone Type 4192 Frequency Response Response dB 15 100 1k 10k 100k Frequency Hz 940893 1e Fig 6 9 Typical free field response 0 incidence for the microphone without protection grid 6 3 6 Random incidence Response A microphone s response in a diffuse sound field is equivalent to its random inci dence response The microphone s random incidence correction curves are shown in Fig 6 6 and Fig 6 8 These corrections are added to the microphone s actuator re sponse obtained using Electrostatic Actuator UA 0033 in order to determine the random incidence response The typical random incidence response with and with out the protection grid are shown in Fig 6 10 and Fig 6 11 The random incidence corrections are calculated from the freefield corrections measured in 5 steps according to Draft IEC 1183 1993 Response dB 5 dB 100 1k 10k 100 k Frequency Hz 940942 1e Fig 6 10 Typical random incidence response for the microphone with Protection Grid DB 3421 BE 1378 12 Falcon Range of Microphone Products 6 11 Microphone Handbook Chapter 6
111. d If the adaptor is used with 1 2 Microphone Pream plifier Type 2669 to obtain an extended low frequency response the frequency re sponse from 100Hz to 10kHz will roll off by less than O 1dB and up to 20kHz by less than 0 5 dB All frequency responses and correction curves are shown with a frequency resolu tion of 1 12 octave 7 3 2 Optimized Response Pressure field Response The frequency response of Low frequency Pressure field 1 2 Microphone Type 4193 meets the requirements of ANSI S1 4 1983 Type 1 and ANSI S1 12 Type M BE 1379 12 Falcon Range of Microphone Products 7 7 Microphone Handbook Chapter 7 Low frequency Pressure field te Microphone T ype 4193 Frequency Response pp punos dU 0 pesod e s qua y UBYM piJ eA si esuodsaJ foueanbaJJ Mo 9U Sue po pelypeds seuoudoJ iu y pue T7vE gd pS uompeod YIM BUOYdOIDIW y JO esuodss ppieJunsssud dAl amp 614 4001 ZH Aouanbal4 940864 1e AL oor 0L L Vo 0 0 IOL IOL IOL o1 S gp esuodseu Br el amp Kjaer Falcon Range of Microphone Products Microphone Handbook Chapter 7 Low frequency Pressure field 1p Microphone Type 4193 Frequency Response 7 3 3 Actuator Response
112. dB 8Hz to 12 5kHz 6 3 Hz to 20kHz 3 15Hz to 20kHz 3 15 Hz to 40kHz 3 15 Hz to 20kHz 0 07 Hz to 20kHz IEC 651 Type O ANSI S1 4 Type 1 ANSI S1 4 Type 1 and Type 1 ANSI ANSI 81 12 Type ANSI S1 12 Type 1 12 CN M cm ETC Optimized Frequency Response Main IEC 651 Type 1 Standards ANSI S1 4 1983 IEC 651 Type 0 IEC 651 Type 1 and Type 1 Freq 3dB Diaphragm Resonance 9 kHz 14 kHz 14 kHz 34kHz 23kHz 23kHz Frequency 14 2 dB A 14 6 dB A 14 5 dB A 20 0 dB A 19 0 dB A 19 0 dB A 14 5dB p 15 3 dB ps 15 5dB is 21 4dB Li 21 3dB ps 21 3dB bb Oo S ae 146dB 146 dB 148 0B 162dB 162dB 162dB Maximum SPL 157 dB 158dB 159 dB 171dB 171dB 171dB Peak Inherent Noise Calibrator Load 3 3 3 EM EM EM 4228 Correction 0 02 dB 0 00 dB 0 00 dB 0 02 dB 0 02 dB 0 02 dB with DP 0776 Operating nsu adis 30 to 150 C 22 to 302 F Temperature perder n EBD aU G can be used up to 300 xC 572 F B with a Sonate sensitivity change Range p io uu With 72210 0e er of typically 0 4 dB which stabilises after one hour corrector Temperature 0 005 dB C 0 001 dB C 0 007 dB C 0 002 dB C 0 002 dB C 0 002 dB C Coefficient Pressure aoe 0 021 dB kPa 0 010 dB kPa 0 010 dB kPa 0 007 dB kPa 0 005 dB kPa 0 005 dB kPa Coefficient Operating 0 to 100 RH without condensation Humidity Range Effect of o Humidity 0 1 dB 10096RH Effect of Vibration
113. distortions given in Table 3 3 and Table 3 4 are valid for a parallel capacitance of O 5pF The distortion is measured at 100Hz but can be assumed to be valid up to approximately 5kHz that is where the diaphragm displacement is predominantly stiffness controlled Distortion meas urement methods for higher frequencies are not available Maximum Sound Pressure L evel In general the microphone should not be exposed to sound pressure levels which produce voltages higher than the maximum input voltage specified for the connect ed preamplifier After an overload the preamplifier needs time to recover and dur ing this recovery period you cannot measure validly The maximum input voltage for most Bruel amp Kj r preamplifiers is 50V with a 130V supply This voltage is BE1375 12 Falcon Range of Microphone Products 3 17 Microphone Handbook Chapter 3 Prepolarized Free field o Microphone Type 4189 Equivalent Volume and Calibrator Load Volume Lower Limit Upper Limit 1 Hz bandwidth ES a A weighted dB Linear 20 je i lt 3 distortion Max SPL Peak at 1 kHz dB 1 kHz 20 kHz dB dB Table 3 3 Dynamic range of the microphone Lower Limit Upper Limit 1 Hz bandwidth Ta Se A weighted dB Linear 20 He a lt 3 distortion Max SPL Peak at 1 kHz dB 1 kHz 20 kHz dB dB LI 19 Table 3 4 Dynamic range of the microphone with 1 2 Microphone Preamplifier Type 2669 produced by a nominal Prepol
114. e see section 1 3 5 7 1 4 Adaptor UC 0211 Adaptor UC 0211 is for use of Low frequency Pressure field 1 2 Microphone Type 4193 with microphone preamplifers Types 2669 and 2639 The adaptor lowers the electrical lower limiting frequency the 3dB point of the microphone preamplifer combination to 0 1 Hz see section 7 3 2 and section 7 3 4 The adaptor s capacitance is 100 pF and it increases the preamplifer s input capaci tance In addition to extending the microphone preamplifer combination s frequency range the adaptor also e Lowers the sensitivity see section 7 2 e Increases the inherent noise see Table 7 4 e Reduces the 3 distrotion limit see Table 7 4 e Slightly changes the frequency response due to varying input capacitance with frequency see Fig 7 20 and section 7 3 1 7 1 5 Recommended Recalibration Interval With normal handling of the microphone and any associated instrument Bruel amp Kj r recommends that the microphone be recalibrated every 2 years Low frequency Pressure field 1 2 Microphone Type 4193 is very stable over this period see section 7 10 to section 7 12 Improper handling is by far the most likely cause of change in the microphone s properties Any damage which causes improper operation can probably be detected using a sound level calibrator In many cases the damage can be seen by carefully inspecting the protection grid and diaphragm 7 2 Sensitivity 7 2 1 Open circuit Sensitivit
115. e 4 19 4191 free field microphone 5 19 4192 pressure field microphone 6 19 4193 pressure field microphone 7 22 Preamplifier 4188 prepolarized microphone 2 28 4189 prepolarized microphone 3 28 4190 free field microphone 4 28 4191 free field microphone 5 28 4192 pressure field microphone 6 28 4193 pressure field microphone 7 32 Preamplifier 1 2 Microphone Type 2669 8 1 connections 8 3 dimensions 8 3 distortion 8 6 dynamic range 8 5 electromagnetic compatibility 8 9 frequency response 8 4 magnetic field 8 9 maximum output 8 6 ordering information 8 11 phase response 8 8 physical dimensions 8 3 pin designations 8 3 specifications 8 11 temperature 8 8 Prepolarized Free field 1 2 Microphone Type 4188 2 1 Prepolarized Free field 1 2 Microphone Type 4189 3 1 Pressure ambient 4188 prepolarized microphone 2 25 4189 prepolarized microphone 3 25 4190 free field microphone 4 25 4191 free field microphone 5 25 4192 pressure field microphone 6 25 4193 pressure field microphone 7 28 Pressure field 1 2 Microphone Type 4192 6 1 Pressure field frequency response 4189 prepolarized microphone 3 13 4190 free field microphone 4 12 4191 free field microphone 5 12 4192 pressure field microphone 6 12 4193 pressure field microphone 7 14 R Rain cover 9 2 Random incidence frequency response 4188 prepolarized microphone 2 12 4189 prepolarized microphone 3 12 4190 free field microphone 4 11 4191 free
116. e Corrector Falcon Range of Microphone Products Microphone Handbook Chapter 2 Prepolarized Free field Ape Microphone Type 4188 Dynamic Range 2 5 Dynamic Range Definition The dynamic range is the range between the upper limit determined by distortion and the inherent noise floor Both limits are influenced by the preamplifier This section gives values for the microphone with and without a preamplifier Inherent Noise The microphone s inherent noise is due to thermal movements of the diaphragm These vary proportionally with the square root of the absolute temperature in K The inherent noise increases with increasing temperature With reference to 20 C the inherent noise changes by 0 5dB at 55 C and by 0 5dB at 12 C The maximum variation of this noise for different samples of Prepolarized Free field 1 2 Microphone Type 4188 is 1dB The preamplifier s effect on the inherent noise of the combined microphone and preamplifier depends on the sensitivity and capacitance of the microphone for 1 2 Microphone Preamplifier Type 2669 see Fig 2 18 and Chapter 8 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 2 Prepolarized Free field 1p Microphone Type 4188 Dynamic Range Sound Pressure Level re 20 Pa dB Microphone d plifier Combination Microphone zd
117. e Handbook Chapter 2 Specifications Overview Prepolarized F ree field ip Microphone Type 4188 2 17 Specifications Overview OPEN CIRCUIT SENSITIVITY 1000 Hz 30dB 2dB re 1 V Pa 31 6 mV Pa POLARIZATION VOLTAGE External 0 V FREQUENCY RESPONSE 0 incidence free field response 12 5Hz to 8kHz 1dB 8 Hz to 12 5kHz 2dB In accordance with IEC 651 Type 1 and ANSI 1 4 1983 LOWER LIMITING FREQUENCY 3 dB 1Hz to 5Hz vent exposed to sound PRESSURE EQUALIZATION VENT Rear vented DIAPHRAGM RESONANCE FREQUENCY 9 kHz typical 90 phase shift CAPACITANCE POLARIZED 12 pF typical at 1000 Hz EQUIVALENT AIR VOLUME 101 3 kPa 65 mm ndividually calibrated CALIBRATOR LOAD VOLUME 250 Hz 208 mm PISTONPHONE TYPE 4228 CORRECTION with DP 0776 40 02 dB TYPICAL CARTRIDGE THERMAL NOISE 14 2dB A 14 5dB Lin UPPER LIMIT OF DYNAMIC RANGE 3 distortion gt 146dB SPL MAXIMUM SOUND PRESSURE LEVEL 157 dB peak OPERATING TEMPERATURE RANGE 30 to 125 C 22 to 257 F Max 70 C 158 F when fitted with Random incidence Corrector DZ 9566 OPERATING HUMIDITY RANGE 0 to 100 RH without condensation STORAGE TEMPERATURE 30 to 70 C 22 to 158 F TEMPERATURE COEFFICIENT 250 Hz 0 005dB C typical for the range 10 to 50 C 2 18 Ordering Information Preamplifier Type 2669 1 Microphone Preamplifier Type 2671 1 Microphone Prea
118. e and Calibrator Load Volume Lower Limit Upper Limit 1 Hz bandwidth E mud A weighted dB Linear 20 pa d lt 3 distortion Max SPL Peak at 1 kHz dB 1 kHz 40 kHz dB dB Table 5 3 Dynamic range of the microphone Lower Limit Upper Limit 1 Hz bandwidth s edd i A weighted dB Linear 20 i d lt 3 distortion Max SPL Peak at 1 kHz dB 1 kHz 40 kHz dB dB 13x IX Table 5 4 Dynamic range of the microphone with 1 2 Microphone Preamplifier Type 2669 produced by a nominal Free field 1 2 Microphone Type 4191 at a Peak level of 166dB re 20uPa The microphone will maintain its charge up to a Peak level of 171dB re 20uPa Above this level the diaphragm and back plate short circuit If this occurs the microphone needs one or two minutes to recharge before it is ready to measure validly We recommend not to expose Free field 1 2 Microphone Type 4191 to levels higher than 171dB Peak 5 6 Equivalent Volume and Calibrator Load Volume Equivalent Volume For some applications it is practical to express the acoustic impedance of the micro phone diaphragm in terms of a complex equivalent volume This makes it easier to evaluate the effect of microphone loading on closed cavities or acoustic calibration couplers The real and imaginary parts of the equivalent volume shown in Fig 5 18 are in parallel They are calculated from a simple R L C series model of the microphone which gives the best o
119. e diaphragm and changes in air mass in the small gap between the diaphragm and the back plate The effects are shown in Fig 7 27 to Fig 7 29 7 28 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field 1p Microphone Type 4193 Effect of Ambient Pressure The typical pressure coefficient at 250Hz for Low frequency Pressure field 1 2 Mi crophone Type 4193 is 0 005 dB kPa Correction dB 3 40kPa change 2 20kPa 1 change Z7 10kPa s change a DE ad 0 E TE 1 500 1k 10k Frequency Hz 50k 940765e Fig 7 27 Typical variation in frequency response normalized at 250 Hz from that at 101 3kPa as a function of changein ambient pressure Response dB 30 500 1k 10k Frequency Hz 50k 940757e Fig 7 28 Typical effect of ambient pressure on actuator response a at 101 3kPa b AOkPa change c 80kPa change d at 2kPa BE 1379 12 Falcon Range of Microphone Products 7 29 Microphone Handbook Chapter 7 Low frequency Pressure field T Microphone T ype 4193 Effect of Humidity Response dB 4
120. e output voltage is dipped We recommend not to expose Prepolarized Free field 1 2 Microphone Type 4188 to levels higher than 157 dB Peak 2 6 Equivalent Volume and Calibrator Load Volume Equivalent Volume For some applications it is practical to express the acoustic impedance of the micro phone diaphragm in terms of an equivalent volume This makes it easier to evalu ate the effect of microphone loading on closed cavities or acoustic calibration couplers The typical equivalent volume of Prepolarized Free field 1 2 Microphone Type 4188 is 65mm Calibrator Load Volume When the microphone with its protection grid is inserted into the coupler of a calibrator it will load the calibrator by a volume of 208mm at 250Hz Load volume correction to Pistonphone Type 4228 Calibration Level with Adaptor DP 0776 0 02 dB BE 1374 12 Falcon Range of Microphone Products 2 19 Microphone Handbook Chapter 2 Prepolarized Free field Ape Microphone Type 4188 Capacitance 2 7 Capacitance Capacitance pF 20 The microphone s impedance is determined by its capacitance In addition the preamplifier s input resistance and capacitance load the microphone This loading determines the electrical lower limiting frequency and the capacitive input attenua tion However with modern preamplifiers this loading is very small and is included in the preamplifier gain G see section 2 2 2 Only in special cases with high capacit
121. emperatures above 200 C it may be discol oured but its functionality will remain unaffected See section 4 10 2 for permanent changes in sensitivity at temperatures above 170 C Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Effect of Temperature The reversible changes are shown in Fig 4 22 as a change in sensitivity and in Fig 4 23 to Fig 4 25 as changes in the frequency response normalized at 250Hz Response dB S 0 0 0 5 2 0 50 0 50 100 150 200 250 300 Temperature C 940875e Fig 4 22 Typical variation in sensitivity at 250Hz as a function of temperature relative to the sensitivity at 20 C Temperature Coefficient 250 Hz 0 007 dB C typical for the range 10 to 50 C BE1376 12 Falcon Range of Microphone Products 4 23 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Effect of Temperature Response dB 1 5 0 5 50 C 0 0 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940774e Fig 4 23 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 4 4 over the temperature range defined by IEC 651 Response dB
122. erature By careful selection of materials optimization of the design and artificial ageing the effect of temperature has been made to be very low The microphone has been designed to operate at temperatures from 30 to 150 C See section 3 10 2 for permanent changes in sensitivity at temperatures at 150 C Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 3 Prepolarized Free field 271 Microphone Type 4189 Effect of Temperature The reversible changes are shown in Fig 3 20 as a change in sensitivity and in Fig 3 21 and Fig 3 22 as changes in the frequency response normalized at 250 Hz Response dB T 0 5 2 0 50 0 50 100 150 200 250 300 Temperature C 940874e Fig 3 20 Typical variation in sensitivity at 250Hz as a function of temperature relative to the sensitivity at 20 C Temperature Coefficient 250 Hz 0 001 dB C typical for the range 10 to 50 C The effect of temperature on the free field response see Fig 3 22 of the microphone is the sum of the following effects e the calculated effect of the change in the speed of sound due to temperature on the 0 incidence free field correction e the measured change in the actuator response due to temperature see Fig 3 21 BE 1375 12 Falcon Range of Microphone Products 3 23 Microphone Handbook Chapter 3 Prepolarized Free field Ape Microphone Type 4189 Effec
123. erature By careful selection of materials optimization of the design and artificial ageing the effect of temperature has been made to be very low The microphone has been designed to operate at temperatures from 30 to 300 C When the microphone is subjected to temperatures above 200 C it may be discol oured but its functionality will remain unaffected See section 5 10 2 for permanent changes in sensitivity at temperatures above 170 C Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 5 Free field n Microphone Type 4191 Effect of Temperature The reversible changes are shown in Fig 5 22 as a change in sensitivity and in Fig 5 23 to Fig 5 25 as changes in the frequency response normalized at 250 Hz Response dB oe 0 0 0 5 2 0 50 0 50 100 150 200 250 300 Temperature C 9408766 Fig 5 22 Typical variation in sensitivity at 250Hz as a function of temperature relative to the sensitivity at 20 C Temperature Coefficient 250 Hz 0 002 dB C typical for the range 10 to 50 C BE1377 12 Falcon Range of Microphone Products 5 23 Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Effect of Temperature Response dB 1 5 0 5 10 C 0 0 50 C 0 5
124. es LEMO LEMO AO 0414 Extension Cable 3m 9 8ft AO 0415 Extension Cable 10m 32 8ft AO 0416 Extension Cable 30m 98 4 ft Cms veo Briel Ki P I Not connected positive EX Power supply Not connected positive z Power supply Not connected negative ground Connected to instrument chassis TEMPERATURE RANGE 20 to 60 C 150 C with increase in noise HUMIDITY Up to 90 RH non condensing EL 4004 xxE xtension Cable length xxm specified by customer Bruel amp Kj r Bruel amp Kj r AO 0027 Extension Cable 3m 9 8ft AO 0028 Extension Cable 10m 32 8 ft AO 0029 Extension Cable 30m 98 4 ft BE1380 12 Falcon Range of Microphone Products Microphone Handbook Chapter 8 T Microphone Preamplifier Type 2669 Ordering Information Microphone Adaptors DB 0375 Adaptor for 1 microphone UA 0035 Adaptor for 1 4 microphone UA 0036 Adaptor for 1 g microphone Other Accessories ZG 0350 JJ 2617 UA 0196 UA 1284 UA 1317 LEMO to 7 pin Bruel amp Kj r adaptor Coaxial Input Adaptor for direct connection to input cables Flexible Extension Rod Stand Microphone Holder Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 9 Accessories BE 1381 12 Falcon Range of Microphone Products Microphone Handbook Chapter 9 Accessories Accessories Available 9 1 Accessories Available 9 1 1 Microphone
125. esent leves at 1 3 octave band centre frequencies BE 1380 12 Falcon Range of Microphone Products 8 5 Microphone Handbook Chapter 8 tb Microphone Preamplifier Type 2669 Dynamic Range Distortion Distortion THD lt 80dB 1000Hz 25V output 3m cable Maximum Output The maximum output of the preamplifier depends on the capacitive load for exam ple extension cables connected to the output If the specified maximum output current of the preamplifier is exceeded the signal will be distorted Fig 8 5 and Fig 8 6 show the distortion limited output when the preamplifier is used with different power supplies Vnus 30 X AS 200 1k 10k 100 k 200 k Frequency Hz 940768e Fig 8 5 Upper limit of dynamic range 3 distortion of pream plifier powered by traditional Bruel amp Kjar power sup plies due to capacitive loading as a function of frequency Note These power supplies limit the maxi mum output current 8 6 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 8 ion Microphone Preamplifier Type 2669 Dynamic Range 100 Vnus Power 50 V 100 V 30 o 2 Qs 10 0 ZA x Z 2e 4 QS 1 200 1k 10k
126. esponse A DU ANTAL Sa UM L b i ll MT WM TTL NUNTNITTE 15 T NAM TOU NS in i HOUT a T j Jol st 15110 20 8 256 Oe Willi TR lll ll NN NANT ul 1 6 3 kHz 8 kHz 10 kHzz INS ex LER N i I AAA ji x T IN il Ill il l lil 940793e Fig 5 14 Typical directional characteristics of the microphone with Protection Grid DB 3421 BE 1377 12 Falcon Range of Microphone Products Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Dynamic Range iil Ili Hl Ill i WW L j mI IT HAUT TOUT MI DM ATTN TNT HH aA TR T WM W Wl AU 1 HH Ii Ji WIR M M UIN uli Jm 5 TU Will Jl IM UU WW Wl Hl dl Illi ui V MOL IN Li HI M THAI JI 31 5 kHz HI 25 kHz 20 kHz 940792e Fig 5 15 Typical directional characteristics of the microphone without protection grid 5 5 Dynamic Range Definition The dynamic range is the range between the upper limit determined by distortion and the inherent noise floor Both limits are influenced by the preamplifier This section gives values for the microphone with and without a preamplifier Inherent Noise The microphone s inherent noise is due to thermal movements of the diaphragm These vary propo
127. ffect shown in Fig 8 9 300 nV VHz 3 200 1k 10k 100k 200k Frequency Hz 940957e Fig 8 9 Effect of temperature on inherent noise Note The preamplifier can withstand temperatures up to 150 C However we do not recommend that it is exposed to this temperature over a longer period of time as the product s life expectancy is drastically reduced In addition we recommend that you don t use high supply voltages with long cables at this temperature for the same reason 8 8 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 8 ion Microphone Preamplifier Type 2669 Effect of Magnetic Fields 8 6 Effect of Magnetic Fields Typically 3 uV for 80A m at 50Hz 8 7 Electromagnetic Compatibility EM C 12 Microphone Preamplifier Type 2669 is constructed such that it is extremely resistant to external electromagnetic radiation This is important when measuring near such things as radar and radio transmitters for example mobile telephones An important prerequisite for acheiving this immunity is that connected instrumen tation also fulfil these requirements and that the preamplifier s termination in the measuring instrument is correctly constructed see Fig 8 10 Bruel amp Kj r equip ment which are designed for connection with 1 2 Microphone Preamplifier Type 2669L and the supplied extension cable fu
128. field Microphone T ype 4193 Dynamic Range Distortion The distortion is determined mainly by the microphone but at the highest opera tion levels the preamplifier also contributes to the distortion see Fig 7 18 and Fig 7 18 Distortion 96 10 and Harmonic 0 1 0 01 135 145 SPL dB 155 165 940499e Fig 7 17 Typical distortion characteristics of the microphone with 1 2 Microphone Preamplifier Type 2669 C and unload ed M 7 18 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 7 Low frequency Pressure field Microphone Type 4193 Dynamic Range Distortion 96 100 id onic grd Harmonic 0 1 135 145 155 SPL dB 165 940500e Fig 7 18 Typical distortion characteristics of the microphone fitted with Adaptor UC 0211 and 1 2 Microphone Preamplifi er Type 2669 The distortion is dependent on the capacitance parallel to the microphone It in creases with increasing capacitance The distortions given in Table 7 3 to Table 7 4 are valid for a parallel capacitance of 0 5 pF The distortion is measured at 100Hz but can be assumed to be valid up to approximately 5kHz that is where the diaphragm displacement is predominantly stiffness controlled Distortion measure
129. field If the vent is not exposed to the sound field the sensitivity increases from OdB at the reference frequency 251 2 Hz to approximately 0 2dB at 1Hz 5 8 Falcon Range of Microphone Products Briel amp Kj r Microphone Handbook Chapter 5 Free field v Microphone Type 4191 Frequency Response For applications where the vent is not exposed to the sound field take care to ensure proper static pressure equalization to prevent static displacement of the diaphragm The microphone s low frequency response is common for all types of sound field The microphone s lower limiting frequency 3dB is between 1 and 2Hz with the vent exposed to the sound field This is measured during production to ensure that specifications are fulfilled 5 3 5 Free field Response The microphone s free field correction curves are shown in Fig 5 6 and Fig 5 8 These corrections are added to the microphone s actuator response obtained using Elecrostatic Actuator UA 0033 in order to determine the free field response at any angle of incidence The typical free field response at 0 incidence with and without the protection grid are shown in Fig 5 7 and Fig 5 9 Correction dB 15 12 5 30 75 2 5 eee ai Vom 150 120 2 5 90 l 8 180 60 7 5
130. field 1 5 Microphone Type 4190 Frequency Response For applications where the vent is not exposed to the sound field take care to ensure proper static pressure equalization to prevent static displacement of the diaphragm The microphone s low frequency response is common for all types of sound field The microphone s lower limiting frequency 3dB is between 1 and 2Hz with the vent exposed to the sound field This is measured during production to ensure that specifications are fulfilled 4 3 5 Free field Response The microphone s free field correction curves are shown in Fig 4 6 and Fig 4 8 These corrections are added to the microphone s actuator response obtained using Elecrostatic Actuator UA 0033 in order to determine the free field response at any angle of incidence The typical free field response at 0 incidence with and without the protection grid are shown in Fig 4 7 and Fig 4 9 Correction dB 15 12 5 30 75 2 5 BNET Fi Random 0 150 90 120 180 2 5 7 5 500 1k 10k Frequency Hz 50k 940802 1e Fig 4 6 Freefidd correction curves for the microphone with Pro tection Grid DB 3420 BE 1376 12 Falcon Range of Microphone Products 4 9 Microphone Handbook Chapter 4
131. free field microphone 5 25 Low frequency Pressure field 1 2 4192 pressure field microphone 6 25 Microphone 7 1 4193 pressure field microphone 7 28 A C About the Microphone Handbook 1 2 Cable 9 2 Accessories 8 12 9 1 extension 8 11 9 2 4188 prepolarized microphone 2 29 LEMO Br el amp Kjar 9 2 4189 prepolarized microphone 3 29 LEMO LEMO 9 2 4190 free field microphone 4 29 Calibration 4191 free field microphone 5 29 charge injection 8 10 4192 pressure field microphone 6 29 CIC 8 10 4193 pressure field microphone 7 32 interval microphone 9 2 4188 prepolarized microphone 2 4 Actuator frequency response 4189 prepolarized microphone 3 5 4188 prepolarized microphone 2 6 4190 free field microphone 4 5 4189 prepolarized microphone 3 7 4191 free field microphone 5 5 BE1382 12 Falcon Range of Microphone Products Index 1 Microphone Handbook Index 4192 pressure field microphone 6 5 4193 pressure field microphone 7 5 Calibration chart 4188 prepolarized microphone 2 3 4189 prepolarized microphone 3 3 4190 free field microphone 4 3 4191 free field microphone 5 3 4192 pressure field microphone 6 3 4193 pressure field microphone 7 3 Calibration equipment 4188 prepolarized microphone 2 28 4189 prepolarized microphone 3 28 4190 free field microphone 4 28 4191 free field microphone 5 28 4192 pressure field microphone 6 28 4193 pressure field microphone 7 32 Calibrator load volume 4188 prepolarized microphone 2 19
132. function Acoustic Calibrator Type 4228 Pistonphone UA 0033 Electrostatic Actuator Other Accessories UA 0254 Set of 6 Windscreens UA 0237 90mm 3 5in UA 0469 Set of 6 Windscreens UA 0459 65 mm 2 6in 7 32 Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 8 1 gt Microphone Preamplifier Type 2669 BE 1380 12 Falcon Range of Microphone Products 8 1 Microphone Handbook Chapter 8 tb Microphone Preamplifier Type 2669 Introduction 8 1 Introduction 8 1 1 Description ZG 0350 not included Fig8 1 1 2 Microphone Preamplifier Type 2669B and 2669L shown with LEMO to 7 pin Br e amp Kjar Adaptor ZG 0350 not included 12 Microphone Preamplifier Type 2669 is a general purpose microphone preampli fier which indudes the following features e Built in calibration facility for testing the complete measurement set up e Thin and flexible cable with wide working temperature range e High output current capability e Works with both dual and single power supplies e Fulfils electromagnetic compatibility EMC requirements EN 50081 1 and pr EN 50081 2 The preamplifier is available in two versions the 2669L and the 2669B The only difference is the connector at the instrument end for the preamplifier socket The 2669L is supplied with a detachable cable with a LEMO connector The 2669B is supplied with a detachable cable with a Br el amp Kj r connector
133. g 100k requency Hz 9408916 Fig 5 9 Typical free field response 0 incidence for the microphone without protection grid 5 3 6 Random incidence Response A microphone s response in a diffuse sound field is equivalent to its random inci dence response The microphone s random incidence correction curves are shown in Fig 5 6 and Fig 5 8 These corrections are added to the microphone s actuator re sponse obtained using Electrostatic Actuator UA 0033 in order to determine the random incidence response The typical random incidence response with and with out the protection grid are shown in Fig 5 10 and Fig 5 11 The random incidence corrections are calculated from the free field corrections measured in 5 steps according to Draft IEC 1183 1993 Response dB 5 dB 100 1k 10k 100 k Frequency Hz 940940 1e Fig 5 10 Typical random incidence response for the microphone with Protection Grid DB 3421 BE 1377 12 Falcon Range of Microphone Products 5 11 Microphone Handbook Chapter 5 Free field Tj Microphone Type 4191 Frequency Response Response dB 5 dB 100k 940941 1e Frequency Hz Fig 5 11 Typical random incide
134. g the protection grid and diaphragm 6 2 Sensitivity 6 2 1 Open circuit Sensitivity The open circuit sensitivity is defined as the sensitivity of the microphone when not loaded by the input impedance of the connected preamplifier the termination is described in IEC 1094 2 The sensitivity is measured for the individual microphone at 251 2Hz and stated on the microphone s calibration chart see section 6 1 2 and data disk see section 6 1 3 The nominal sensitivity is shown in Table 6 2 Nominal open circuit sensitivity Accepted Deviation dB Table 6 2 Nominal open circuit sensitivity 6 2 2 Loaded Sensitivity When loaded by a preamplifier the sensitivity of the microphone is given by where Sc overall sensitivity of microphone and preamplifier combination So open drcuit sensitivity of microphone G voltage gain of microphone and preamplifier combination in dB With Microphone Preamplifier Type 2639 G O 1dB With 1 2 Microphone Preamplifier Type 2669 G 0 2 dB BE1378 12 Falcon Range of Microphone Products 6 5 Microphone Handbook Chapter 6 Pressure field z Microphone Type 4192 Frequency Response Example Loaded sensitivity of typical microphone with 1 2 Microphone Preamplifier Type 2669 Sc 38 3 0 2 38 5 dB 6 2 3 K factor Some types of Br el amp Kj r instruments use the K factor correction factor or the Ko factor open circuit correction factor for calibration K
135. gein ambient pressure Response dB 30 500 1k 10k Frequency Hz 50k 940757e Fig 6 27 Typical effect of ambient pressure on actuator response a at 101 3kPa b AOkPa change c 80kPa change d at 2kPa 6 26 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 6 Pressure field lp Microphone Type 4192 Effect of Humidity Response dB 4 10 100 Ambient Pressure kPa 1000 9407616 Fig 6 28 Typical variation in sensitivity at 250Hz from that at 101 3kPa as a function of ambient pressure 6 13 Effect of Humidity Due to the microphone s high leakage resistance humidity has in general no effect on the microphone s sensitivity or frequency response The microphone has been tested according to IEC 68 2 3 and the effects of humidty on the sensitivity at 250Hz and the frequency response have been found to be less than 0 1dB at up to 95 RH non condensing and 40 C 6 14 Effect of Vibration The effect of vibration is determined mainly by the mass of the diaphragm and is at its maximum for vibrations applied normal to the diaphragm A vibration signal of 1m s RMS normal to the diaphragm typically produces an equivalent Sound Pres sure Level of 65 5dB for a microphone fitted with Protection Grid DB 34
136. gged microphone is built to ensure high stability under a variety of condi tions For example the stainless steel alloy diaphragm withstands polluted industri al environments The diaphragm damping ring is firmly secured to ensure the microphones reliability even when the microphone is used without its protection grid When the microphone is used without its protection grid it can be easily flush mounted or inserted into closed volumes as it can be supported by the dia phragm damping ring provided that a force of less than 5Newtons is applied Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 3 Prepolarized Free field oy Microphone Type 4189 Introduction The microphone is supplied with individual calibration data on a calibration chart and on a 31 2 data disk in a case This case can also contain a 1 2 Microphone Preamplifier Type 2669 3 1 2 The Calibration Chart Each microphone is supplied with an individual calibration chart see Fig 3 2 which gives the microphone s open circuit sensitivity polarized capacitance and free field and actuator frequency responses Prepolarized Free field P a 7 LIH M EMEN EMEN 1 2 Microphone Type 41 89 d Dotted Curve Sh ws Typical Response Free field Response 0 Calibration Chart ea eei I3 LI Serial No 418911A lee Ld Open circuit Sensitivity So 26 6 dB re 1V Pa L abe aiii Equivalent to 46 8 mv Pa EL ST Uncertainty 95 confidence level 0 2 d
137. h temperature Stability The diaphragm is made of a stainless steel alloy The alloy has been carefully selected and is very resistant to heat This means that the diaphragm tension and therefore the sensitivity remain the same even after several hours operation at high temperature The microphone has been tested at temperatures up to 300 C Below 170 C no changes occur At 170 C the sensitivity can be permanently changed within the first 10hours by less than 0 025 dB After this the sensitivity can be permanently changed within the next 100 hours by a similar value At 300 C the sensitivity can be permanently changed within the first hour by 0 4dB After this the sensitivity can be permanently changed within the next 10hours by less than 0 4 dB BE1378 12 Falcon Range of Microphone Products 6 21 Microphone Handbook Chapter 6 Pressure field z Microphone Type 4192 Effect of Temperature Note Spedial adaptors inserted between the microphone and preamplifier must be made for high temperature applications in order to protect the preampifier from heat conduction and radiation 6 10 3 Long term Stability Over a period of time the mechanical tension in the diaphragm will decrease due to stretching within the foil This mechanism which in principle causes an increased sensitivity is however very weak for the microphone Measurement of this mecha nism is not possible at room temperature At present no exact
138. hapter 7 Low frequency Pressure field 2 Microphone Type 4193 Electromagnetic Compatibility 7 16 Electromagnetic Compatibility See Chapter 8 7 17 Specifications Overview 7 17 1 Low frequency Pressure Response 1 2 Microphone Type 4193 OPEN CIRCUIT SENSITIVITY 250 Hz 38dB t1 5dB re 1 V Pa 12 5 mV Pa POLARIZATION VOLTAGE External 200 V FREQUENCY RESPONSE Pressure field response 0 12 Hz to 12 5kHz 1dB 0 07 Hz to 20kHz 2dB In accordance with ANSI S1 4 1983 Type 1 and ANSI 81 12 Type M LOWER LIMITING FREQUENCY 3 dB 0 01 Hz to 0 05 Hz vent exposed to sound PRESSURE EQUALIZATION VENT Side vented DIAPHRAGM RESONANCE FREQUENCY 23 kHz typical 90 phase shift CAPACITANCE POLARIZED 18 pF typical at 250 Hz EQUIVALENT AIR VOLUME 101 3 kPa 8 8 mm ndividually calibrated 7 17 2 Adaptor UC 0211 LOWER CUT OFF FREQUENCY 0 1 Hz with 1 2 Microphone Preamplifier Type 2669 EFFECT ON HIGH FREQUENCY RESPONSE 100Hz to 10kHz 0 1dB 100Hz to 20kHz 0 5dB CALIBRATOR LOAD VOLUME 250 Hz 190 mm PISTONPHONE TYPE 4228 CORRECTION with DP 0776 40 02 dB TYPICAL CARTRIDGE THERMAL NOISE 19 0dB A 21 3dB Lin UPPER LIMIT OF DYNAMIC RANGE 3 distortion gt 162dB SPL MAXIMUM SOUND PRESSURE LEVEL 171 dB peak OPERATING TEMPERATURE RANGE 30 to 150 C 22 to 302 F can be used up to 300 C 572 F but with a permanent sensitivity change of t
139. has been designed to operate at temperatures from 30 to 300 C When the microphone is subjected to temperatures above 200 C it may be discol oured but its functionality will remain unaffected See section 7 10 2 for permanent changes in sensitivity at temperatures above 170 C The reversible changes are shown in Fig 7 23 as a change in sensitivity and in Fig 7 26 to Fig 7 26 as changes in the frequency response normalized at 250Hz Response dB p dB us 0 0 0 5 2 0 50 0 50 100 150 200 250 300 Temperature C 940876e Fig 7 23 Typical variation in sensitivity at 250Hz as a function of temperature relative to the sensitivity at 20 C Temperature Coefficient 250 Hz 0 002 dB C typical for the range 10 to 50 C 7 26 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field 21 Microphone Type 4193 Effect of Temperature Response dB 1 5 0 5 0 0 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940776e Fig 7 24 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 7 4 over the temperature range defined by IEC 651 Response dB
140. he optimized response A microphone s re sponse in a diffuse field is equivalent to its random incidence response This section shows the microphone s typical free field pressure field and random incidence responses together with the microphone s typical actuator response ob tained using Electrostatic Actuator UA 0033 The low frequency response described in section 4 3 4 is common for all types of response 4 6 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 4 Free field 1 2 Microphone Type 4190 Frequency Response All frequency responses and correction curves are shown with a frequency resolu tion of 1 12 octave 4 3 2 Optimized Response 0 incidence Free field Response Response dB 5 _ 10 3 i5 i 1k 10k 100k Frequency Hz 940895e Fig4 3 Typical free field response of the microphone with Protection Grid DB 3420 and the micro phone s specified tolerances The low frequency response is valid when the vent is exposed to the sound fidd The frequency response of Free field 1 2 Microphone Type 4190 meets the require ments of IEC 651 Type 0 and Type 1 4 3 3 Actuator Response The microphone s frequency response is determined by adding corrections for the type of sound field to its actu
141. he protection grid is significantly reinforced Therefore the microphone can withstand mechanical shocks better than traditional Bruel amp Kj r microphones The sensitivity change of the microphone is less than 0 1dB after a free fall of 1m onto a solid hardwood block re IEC 68 2 32 This improved mechanical stability makes Free field 1 2 Microphone Type 4190 well suited for surface mounting and for mounting in small couplers as no mechani cal adaptor is required to protect the diaphragm clamping ring The microphone can be supported by the diaphragm damping ring directly on the coupler s surface Any force of less than 5Newtons will cause a change in sensitivity of less than 0 005 dB This makes the microphone well suited for fitting in small plane wave couplers used for reciprocity calibration and any other small coupler with a well defined volume 4 10 2 High temperature Stability The diaphragm is made of a stainless steel alloy The alloy has been carefully selected and is very resistant to heat This means that the diaphragm tension and therefore the sensitivity remain the same even after several hours operation at high temperature The microphone has been tested at temperatures up to 300 C Below 170 C no changes occur At 170 C the sensitivity can be permanently changed within the first 10hours by less than 0 025 dB After this the sensitivity can be permanently changed within the next 100 hours by a similar value At 3
142. high leakage resistance humidity has in general no effect on the microphone s sensitivity or frequency response The microphone has been tested according to IEC 68 2 3 and the effects of humidty on the sensitivity at 250Hz and the frequency response have been found to be less than O 1dB at up to 95 RH non condensing and 40 C 2 26 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 2 Prepolarized Free field Ton Microphone Type 4188 Effect of Vibration 2 14 Effect of Vibration The effect of vibration is determined mainly by the mass of the diaphragm and is at its maximum for vibrations applied normal to the diaphragm A vibration signal of 1m s RMS normal to the diaphragm typically produces an equivalent Sound Pres sure Level of 63 5dB for a microphone fitted with Protection Grid DD 0525 2 15 Effect of Magnetic Field The effect of a magnetic field is determined by the vector field strength and is normally at its maximum when the field direction is normal to the diaphragm A magnetic field strength of 80A m at 50Hz the test level recommended by IEC and ANSI normal to the diaphragm produces a typical equivalent Sound Pressure Lev el of 7dB Higher frequency components in the microphone output become domi nant at field strengths greater than 500 to 1000 A m 2 16 Electromagnetic Compatibility See Chapter 8 BE 1374 12 Falcon Range of Microphone Products 2 27 Microphon
143. icrophone 5 7 4192 pressure field microphone 6 7 4193 pressure field microphone 7 9 free field 4188 prepolarized microphone 2 8 4189 prepolarized microphone 3 9 4190 free field microphone 4 9 4191 free field microphone 5 9 4192 pressure field microphone 6 9 4193 pressure field microphone 7 10 low frequency 4188 prepolarized microphone 2 7 4189 prepolarized microphone 3 8 4190 free field microphone 4 8 4191 free field microphone 5 8 4192 pressure field microphone 6 8 4193 pressure field microphone 7 10 optimized 4188 prepolarized microphone 2 6 4189 prepolarized microphone 3 7 4190 free field microphone 4 7 4191 free field microphone 5 7 4192 pressure field microphone 6 7 4193 pressure field microphone 7 7 pressure field 4189 prepolarized microphone 3 13 4190 free field microphone 4 12 4191 free field microphone 5 12 4192 pressure field microphone 6 12 4193 pressure field microphone 7 14 random incidence 4188 prepolarized microphone 2 12 4189 prepolarized microphone 3 12 4190 free field microphone 4 11 4191 free field microphone 5 11 4192 pressure field microphone 6 11 4193 pressure field microphone 7 13 resolution 4188 prepolarized microphone 2 6 4189 prepolarized microphone 3 4 3 7 4190 free field microphone 4 4 4 4191 free field microphone 5 4 5 4192 pressure field microphone 6 4 7 4193 pressure field microphone 7 4 7 7 7 H Humidity 4188 prepolarized microphone 2
144. id are shown in Fig 6 7 and Fig 6 9 Correction dB 15 12 5 7 5 2 5 i Random 7 90 0 180 150 120 2 5 5 5 5 7 5 10 500 1k 10k Frequency Hz 50k 940798 1e Fig 6 6 Freefidd correction curves for the microphone with Pro tection Grid DB 3421 BE 1378 12 Falcon Range of Microphone Products 6 9 Microphone Handbook Chapter 6 Pressure field ip Microphone Type 4192 Frequency Response Response dB 15 Frequency Hz 100k 940892 1e Fig 6 7 Typical free field response 0 incidence for the microphone with Protection Grid DB 3421 15 dB 12 5 10 0 7 5 30 5 2 5 MM 60 Random 7 0 E 150 120 90 25 180 Y t 7 5 10 500 1k 10k Frequency Hz 50k 940797 le Fig 6 8 Freefidd correction curves for the microphone without protection grid 6 10 Falcon Range of Microphone Produ
145. ield 1 2 Micro phone Type 4189 is 0 010 dB kPa well within the 0 03 dB kPa limits required for Type 1 sound level meters by IEC 651 Correction dB 3 40kPa change 1 20kPa change E NZ 10kPa A change 500 1k 10k Frequency Hz 50k 940763e Fig 3 23 Typical variation in frequency response normalized at 250 Hz from that at 101 3kPa as a function of changein ambient pressure BE1375 12 Falcon Range of Microphone Products 3 25 Microphone Handbook Chapter 3 Prepolarized Free field lp Microphone Type 4189 Effect of Humidity Response dB 30 20 20 500 1k 10k Frequency Hz 50k 940754e Fig 3 24 Typical effect of ambient pressure on actuator response a at 101 3kPa b AOkPa change c 80kPa change d at 2kPa Response dB 4 1 10 100 Ambient Pressure kPa 1000 940759e Fig 3 25 Typical variation in sensitivity at 250Hz from that at 101 3kPa as a function of ambient pressure 3 13 Effect of Humidity Due to the microphone s high leakage resistance humidity has in general no effect on the microphone
146. ing frequency is measured to ensure that it is within the specified tolerances see Fig 7 3 7 1 3 Data Disk SIHHHHHHEBKM Sensitivity calibration 251 2Hz AIIHHHHHEBKMS Actuator response 200 Hz 22kHz PAIHHHHHEBEBKRD Pressure field response 1Hz 22kHz 4193L BKT Low frequency response 1Hz 190Hz Table 7 1 Calibration data and corrections contained on the data disk Note 444H is the micro phone s serial number a Individual calibration data measured b Low frequency response combined with actuator response and free field corrections c Typical response for Low frequency Pressure field 1 2 Microphone Type 4193 d Corrections for Low frequency Pressure field 1 2 Microphone Type 4193 The 31 2 data disk supplied with each microphone supplements the calibration chart It contains individual calibration data and correction curves see Table 7 1 with a frequency resolution of 1 12 octave as comma separated ASCII text files un der the DATA directory 7 4 Falcon Range of Microphone Products Briel amp Kj r Microphone Handbook Chapter 7 Low frequency Pressure field oy Microphone T ype 4193 Sensitivity These text files can be viewed on Microsoft Windows using the Bruel amp Kjaer Microphone Viewer program BK MIC EXE supplied on the disk They can also be accessed by a suitable spreadsheet for further processing or printing Bruel amp Kj r Microphone Viewer must be installed before us
147. ion curves are shown in Fig 4 6 and Fig 4 8 These corrections are added to the microphone s actuator re sponse obtained using Electrostatic Actuator UA 0033 in order to determine the random incidence response The typical random incidence response with and with out the protection grid are shown in Fig 4 10 and Fig 4 11 The random incidence corrections are calculated from the free field corrections measured in 5 steps according to Draft IEC 1183 1993 Response dB 5 dB 1 100 k 940938 1e Frequency Hz Fig 4 10 Typical random incidence response for the microphone with Protection Grid DB 3420 BE 1376 12 Falcon Range of Microphone Products 4 11 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Frequency Response Response dB 5 dB 100 1k 10k 100 k Frequency Hz 940939 1e Fig 4 11 Typical random incidence response for the microphone without protection grid 4 3 7 Pressure field Response The microphone s pressure field correction curve is shown in Fig 4 12 This correc tion is added to the microphone s actuator response obtained using Electrostatic Actuator UA 0033 in order to determine
148. is 1dB 4 14 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Dynamic Range The preamplifier s effect on the inherent noise of the combined microphone and preamplifier depends on the sensitivity and capacitance of the microphone for 1 2 Microphone Preamplifier Type 2669 see Fig 4 16 and Chapter 8 Sound Pressure Level re 20 uPa dB Microphone and Preamplifier Combination ier Frequency Hz 940718e Fig4 16 l 3 octave band inherent noise spectra The shaded bar graphs are the broad band 20Hz to 20kHz noise leves and the white bar graphs the A weighted noise Ieas of the micro phone M 1 Microphone Preamplifier Type 2669 P and microphone and preamplifier combination C BE 1376 12 Falcon Range of Microphone Products 4 15 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Dynamic Range Distortion The distortion is determined mainly by the microphone but at the highest opera tion levels the preamplifier also contributes to the distortion see Fig 4 17 Distortion 96 10 gnd Harmonic grd Harmonic 0 1 0 01 125 135 145 SPL dB 155 940498e Fig 4 17 Typical dist
149. ive loading does the fall in capacitance with frequency have to be taken into account Typical capacitance at 1000 Hz 12 pF ik Hz 10k 100k Frequency Hz 940597e Fig 2 20 Variation of capacitance with frequency 2 8 Polarization Voltage The polarization charge of Prepolarized Freefield 1 2 Microphone Type 4188 is negative Therefore the output voltage is positive for a positive pressure applied to the diaphragm At the factory the microphone is polarized with a permanent charge Therefore do not apply an external voltage to the microphone In order to ensure the correct polarization during use the centre terminal of the microphone must be kept at the same DC potential as the housing Therefore connect the preamplifier pin normally used for the polarization voltage supply to ground potential OV It is not sufficient to leave it open circuit Falcon Range of Microphone Products Bruel amp Kj r Microphone Handbook Chapter 2 Prepolarized Free field p Microphone Type 4188 Leakage Resistance Accidentally connecting the microphone to a 200V external polarization will not damage the microphone However the sensitivity will fall by at least 8dB and the frequency response will change by 1 or 2dB We do not recommend use in this way Warning Static electricity can destroy the micr
150. lamping ring provided that a force of less than 5Newtons is applied The microphone is supplied with individual calibration data on a calibration chart and on a 31 2 data disk in a case This case can also contain a 1 2 Microphone Preamplifier Type 2669 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 5 Free field Microphone Type 4191 Introduction 5 1 2 The Calibration Chart Each microphone is supplied with an individual calibration chart see Fig 5 2 which gives the microphone s open circuit sensitivity polarized capacitance and free field and actuator frequency responses Free field 1 2 Microphone Type 41 91 Dotted Curve Shows Typical Response Free field Response Sound Incidence Bruel amp Kjzer Calibration Chart 1 05 i LLLI Serial No 419111A Open circuit Sensitivity So 37 9 dB re 1V Pa aet TTT TT Equivalent to 12 7 mviPa Uncertainty 95 confidence level 0 2 dB Capacitance 18 2 pF Valid At Temperature 23 C Ambient Static Pressure 101 3 kPa T Actuator Re Relative Humidity 50 Frequency 250 Hz Polarization Voltage external 200 V Sensitivity Traceable To DPLA Danish Primary Laboratory of Acoustics NIST National Institute of Standards and Technology USA IEC 1094 4 Type WS 2 F Sound Incidence Environmental Calibration Conditions
151. lfil the requirements for immunity to external electromagnetic radiation Generator for charge injection Preamplifier input internal view Polarization Voltage Fig 8 10 Simplifed electronic construction of input circuit of 1 2 Microphone Preamplifier Type 2669 for ensuring compli ance with EMC requirements Note Bruel amp Kj r equipment typically those having the traditional Bruel amp Kjaer microphone socket do not fulfil these strict immunity regirements 1 2 Microphone Preamplifier Type 2669 conforms to EMC requirements EN 50081 1 and pr EN 50081 2 when connected to an instrument that also conforms to these regulations BE1380 12 Falcon Range of Microphone Products 8 9 Microphone Handbook Chapter 8 Microphone Preamplifier Type 2669 Br el amp Kjaer s Patented Charge injection Calibration Technique 8 8 Br el amp Kjar s Patented Charge injection Calibration Technique This is a new patented technique for verifying the entire measurement set up in cluding the microphone the preamplifier and the connecting cable see Fig 8 11 The Charge injection Calibration CI C technique is a method for remotely verifying the condition of the entire measurement set up including the microphone This is a great improvement over the earlier insert voltage calibration method which virtually ignores the state of the microphone The CIC technique is very sensitive to any change in the microphone s capacit
152. ll coupler with a well defined volume 2 10 2 High temperature Stability The diaphragm is made of a stainless steel alloy The alloy has been carefully selected and is very resistant to heat This means that the diaphragm tension and therefore the sensitivity remain the same even after several hours operation at high temperature The microphone has been tested at temperatures up to 125 C Below 125 C no changes occur At 125 C the sensitivity can be permanently changed within the first hour by less than 0 1dB After this the sensitivity can be permanently BE 1374 12 Falcon Range of Microphone Products 2 21 Microphone Handbook Chapter 2 Prepolarized Free field Ap Microphone Type 4188 Effect of Temperature changed within the next 10hours by a similar value These changes are due to decreasing charge of the electret Note Spedial adaptors inserted between the microphone and preamplifier must be made for high temperature applications in order to protect the preampifier from heat conduction and radiation 2 10 3 Long term Stability The microphone s long term stability is determined by the stability of the electret charge The charge decays very slowly even in humid conditions See Br el amp Kjaer Technical Review no 4 1979 and the spedifications given below 71000 years dB dry air at 20 C gt 10 hours dB dry air at 125 C gt 40 years dB air at 20 C 90 RH gt 6 months dB air at 50 C 90 R
153. m field sensitivity is the same as the pressure sensitivity The free field sensitivity at 1000Hz is 0 15dB higher Free field calibration with Sound Level Calibrators at 1000 Hz Adjust the Sound Level Meter or other measurement equipment to indicate 0 15dB lower SPL than the actual SPL produced by the calibrator Polarization Voltage external 0 V BC0211 11 1 i N G Date 1 July 1993 Signature e Refer to the 4188 Product Data for further information See also rear side Typical free field response for 0 incidence E Typical random field response with random incidence corrector 2 without random incidence corrector i b 1 f pek 1 0 0 ap a 2 2 3 y response satis ype 3 y resp salistle yp 20 50 100 200 500 1k 2k 5k 10k 20k 930776e 50 100 200 500 1k 2k 5k 10k 20k 1 Fig 2 2 Microphone calibration chart front and back Open circuit Sensitivity The stated open circuit pressure sensitivity is valid at the reference frequency 1000 Hz for random incidence and pressure field conditions The free field sensitiv ity at the reference frequency 1000Hz is 0 11dB higher than the pressure sensi tivity Ambient Conditions The ambient conditions are measured continuously during calibration at the factory The calibration results obtained at the measured environmental calibration condi tions are corrected to the stated reference ambient conditions 23 C 101 325kPa and
154. manently changed within the next 100 hours by a similar value At 300 C the sensitivity can be permanently changed within the first hour by 0 4dB After this the sensitivity can be permanently changed within the next 10hours by less than 0 4 dB Note Spedial adaptors inserted between the microphone and preamplifier must be made for high temperature applications in order to protect the preampifier from heat conduction and radiation 7 10 3 Long term Stability Over a period of time the mechanical tension in the diaphragm will decrease due to stretching within the foil This mechanism which in principle causes an increased sensitivity is however very weak for the microphone Measurement of this mecha nism is not possible at room temperature At present no exact value can be given for the microphone s long term stability but measured changes at high temperatures indicate that Low frequency Pressure field 1 5 Microphone Type 4193 is more than 10 times more stable than traditional Bruel amp Kj r microphones This indicates typical changes of less than 1dB in 5000 years BE1379 12 Falcon Range of Microphone Products 7 25 Microphone Handbook Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Effect of Temperature 7 11 Effect of Temperature By careful selection of materials optimization of the design and artificial ageing the effect of temperature has been made to be very low The microphone
155. microphone 5 8 4192 pressure field microphone 6 8 4193 pressure field microphone 7 10 optimized 4188 prepolarized microphone 2 6 4189 prepolarized microphone 3 7 4190 free field microphone 4 7 4191 free field microphone 5 7 4192 pressure field microphone 6 7 4193 pressure field microphone 7 7 pressure field 4189 prepolarized microphone 3 13 4190 free field microphone 4 12 4191 free field microphone 5 12 4192 pressure field microphone 6 12 4193 pressure field microphone 7 14 random incidence 4188 prepolarized microphone 2 12 4189 prepolarized microphone 3 12 4190 free field microphone 4 11 4191 free field microphone 5 11 4192 pressure field microphone 6 11 4193 pressure field microphone 7 13 resolution 4188 prepolarized microphone 2 6 4189 prepolarized microphone 3 4 3 7 S Sensitivity loaded 4188 prepolarized microphone 2 4 4189 prepolarized microphone 3 5 4190 free field microphone 4 5 4191 free field microphone 5 5 4192 pressure field microphone 6 5 4193 pressure field microphone 7 6 open circuit 4188 prepolarized microphone 2 4 4189 prepolarized microphone 3 5 4190 free field microphone 4 5 4191 free field microphone 5 5 4192 pressure field microphone 6 5 4193 pressure field microphone 7 5 Sound Pressure L evel maximum 4188 prepolarized microphone 2 18 4189 prepolarized microphone 3 17 4190 free field microphone 4 16 4191 free field microphone 5 16 4192 pressure field microphone 6 16 419
156. mplifier Calibration Equipment Type 4231 Sound Level Calibrator Type 4226 Multifunction Acoustic Calibrator Type 4228 Pistonphone PRESSURE COEFFICIENT 250 Hz 0 021 dB kPa typical INFLUENCE OF HUMIDITY 0 1 dB 100 RH VIBRATION SENSITIVITY 1000 Hz Typically 63 5 dB equivalent SPL for 1 m s axial acceleration MAGNETIC FIELD SENSITIVITY Typically 7 dB SPL for 80 A m 50 Hz field ESTIMATED LONG TERM STABILITY gt 1000 years dB dry air at 20 C gt 10 hours dB dry air at 125 C gt 40 years dB air at 20 C 90 RH gt 6 months dB air at 50 C 90 RH DIMENSIONS Diameter 13 2mm 0 52 in with grid 12 7 mm 0 50 in cartridge housing 14 35mm 0 56in with DZ 9566 14 9 mm 0 59 in with grid 14 0 mm 0 55 in without grid 16 7 mm 0 66 in with DZ 9566 Thread for preamplifier mounting 11 7 mm 60 UNS Height The data above are valid at 23 C 101 3 kPa and 5096 RH unless otherwise specified UA 0033 Electrostatic Actuator Falcon Range of Microphone Products Microphone Handbook Br el amp Kj r Chapter 2 Prepolarized Free field 1p Microphone Type 4188 Ordering Information Other Accessories UA 0308 Dehumidifier UA 0254 Set of 6 Windscreens UA 0237 90mm 3 5in UA 0469 Set of 6 Windscreens UA 0459 65 mm 2 6in BE 1374 12 Falcon Range of Microphone Products 2 29 Microphone Handbook Chapter 2 Prepolarized Free field
157. n capacitance with frequency have to be taken into account 250 V 200 V 150 V 28V 100 1k Hz 10k 100k Frequency Hz 940605e Fig 7 20 Variation of capacitance with polarization voltage and frequency Typical capacitance at 250 Hz 18 pF The capacitance is individually calibrated and stated on the calibration chart 7 8 Polarization Voltage Generally a microphone is operated at its nominal polarization voltage For Low frequency Pressure field 1 2 Microphone Type 4193 this is 200V As this polariza Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field Tp Microphone Type 4193 Polarization Voltage tion voltage is positive the output voltage is negative for a positive pressure ap plied to the diaphragm In special cases where there is a risk of preamplifer overload or there are long cables to be driven choose a lower voltage This will cause a lower sensitivity see Fig 7 21 and a change in the frequency response see Fig 7 22 Response dB 200 500 Po Voltage V 940683e Fig 7 21 Variation in sensitivity at 250Hz as a function of po larization voltage
158. nce The typical free field response at 0 incidence with and without the protection grid and with Random Incidence Corrector DZ9566 are shown in Fig 2 7 Fig 2 9 and Fig 2 11 respectively Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 2 Prepolarized Free field Tyo Microphone T ype 4188 Frequency Response Correction dB 15 12 5 0 10 30 7 5 5 60 7 Random 2 5 0 180 90 2 5 150 120 7 5 10 500 1k 10k Frequency Hz 50k 940795 1e Fig 2 6 Freefidd correction curves for the microphone with Pro tection Grid DD 0525 Response dB 5 10 20 100 1k 10k 100 k Frequency Hz 940884e Fig 2 7 Typical free field response 0 incidence for the microphone with Protection Grid DD 0525 BE 1374 12 Falcon Range of Microphone Products 2 9 Microphone Handbook Chapter 2 Prepolarized Free field Ty Microphone Type 4188 Frequency Response Correction dB
159. nce response for the microphone without protection grid 5 3 7 Pressure field Response The microphone s pressure field correction curve is shown in Fig 5 12 This correc tion is added to the microphone s actuator response obtained using Electrostatic Actuator UA 0033 in order to determine the pressure field response The typical pressure field response is shown in Fig 5 13 In practice the pressure field response is often regarded as being equal to the actuator response as the difference between them is small compared to the uncer tainty related to many types of measurement Correction dB 4 P ik 10k 100 k requency Hz 9408676 Fig 5 12 Pressurefield correction for the microphone 5 12 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 5 Free field 1p Microphone Type 4191 Directional Characteristics Response dB 5 100k 20 1k 10k Frequency Hz 940871e 100 Fig 5 13 Typical pressure field response for the microphone 5 4 Directional Characteristics Typical directional characteristics are given in Fig 5 14 and Fig 5 15 The character istics are normalised relative to the 0 r
160. ndbook Chapter 5 Free field Tym Microphone Type 4191 Polarization Voltage Response dB 00 500 Po Voltage V 940682e Fig 5 20 Variation in sensitivity at 250Hz as a function of po larization voltage relative to the sensitivity with a polar ization voltage of 200V Response dB 2 5 2 1 28V 0 150 V 250 V 1 2 2 5 100 1k Hz 10k Frequency Hz 100k 940607e Fig 5 21 Effect of polarization voltage on frequency response The curves show the difference from the response with a polarization voltage of 200V normalised at 250 Hz 5 20 Falcon Range of Microphone Products Microphone Handbook Br el amp Kj r Chapter 5 Free field T Microphone Type 4191 Leakage Resistance 5 9 Leakage Resistance To maintain the correct polarization voltage on the microphone the microphone s leakage resistance must be at least 1000 times greater than the supply resistance of the polarization charge even under the most severe environmental conditions This resistance which is generally placed in the preamplifier is typically 10 to 1019 o Bruel amp Kj r microphones have a very high leakage resistance which is greater than 5x10 Q
161. nduded in the preamplifier gain G see section 4 2 2 Only in special cases with high capacitive loading does the fall in capacitance with frequency have to be taken into account 250 V 200 V 150 V 28V Hz 10k 100k Frequency Hz 9406016 Fig 4 19 Variation of capacitance with polarization voltage and frequency Typical capacitance at 250Hz 16 pF The capacitance is individually calibrated and stated on the calibration chart 4 8 Polarization Voltage Generally a microphone is operated at its nominal polarization voltage For Free field 1 2 Microphone Type 4190 this is 200V As this polarization voltage is posi tive the output voltage is negative for a positive pressure applied to the dia phragm In special cases where there is a risk of preamplifer overload or there are long cables to be driven choose a lower voltage This will cause a lower sensitivity see Fig 4 20 and a change in the frequency response see Fig 4 21 BE1376 12 Falcon Range of Microphone Products 4 19 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Polarization Voltage Response dB 5 10 20 50 100 200 500 Po Voltage
162. ng term stability As a result of all this Bruel amp Kj r has extended their warranty period to three years No ecologically damaging materials are used in the manufacture and packaging of these microphones 1 3 2 Selecting a Microphone for Your Needs To make sure you select the right microphone to match your needs you will proba bly have to consider one or more of the following e Standards IEC or ANSI e Frequency range e Polarization e Sound field 1 2 Falcon Range of Microphone Products Bruel amp Kj r Microphone Handbook Chapter 1 Introduction The Microphones The following together with the flow chart shown in Fig 1 1 and the comparitive list of specifications shown in Table 1 2 will help you to make your decision Yes Standards P pbi Free field or Pressure field Type 0 and 1 12 Type 1 Type 0 Audio freq or Type 1 Extended freq Type 1 Extended freq External Frequency Polarization Analysis Y 4192 4191 4190 4188 4193 4192 4191 4188 DZ 9566 4193 940369e Fig 1 1 Flow chart to help you choose the right microphone in the Falcon Range for your needs M easurement Standards You can use these microphones in noise measurement systems satisfying either ANSI or IEC standards or their local equivalents The microphones use only 5096 to 7096 of the tolerances allowed by these standards Frequency Ranges All six microphones cover the audio frequency range If however
163. nge of Microphone Products 5 3 Microphone Handbook Chapter 5 Free field ty Microphone Type 4191 Introduction The lower curve on the calibration chart is the individual microphone s electrostatic actuator response measured with Electrostatic Actuator UA 0033 This response is used to determine free field responses at angles of incidence other than 0 and responses in other types of sound field The individual microphone s electrostatic actuator response is also available on the data disk The dotted part of the curve is the typical low frequency response Each micro phone s individual lower limiting frequency is measured to ensure that it is within the specified tolerances see Fig 5 3 5 1 3 Data Disk The 31 2 data disk supplied with each microphone supplements the calibration chart It contains individual calibration data and correction curves see Table 5 1 with a frequency resolution of 1 12 octave as comma separated ASCII text files un der the DATA directory SAHHHHEHHEBKM Sensitivity calibration 251 2Hz AIHHHHHRHIBKM Actuator response 200 Hz 40 kHz FIHHHHHEHEBKRD Free field response 1Hz 40kHz 4191L BKT Low frequency response 1Hz 190 Hz Table5 1 Calibration data and corrections contained on the data disk Note H HHHHH is the micro phone s serial number a Individual calibration data measured b Low frequency response combined with actuator response and free field corrections c Typical
164. octave A weighted dB Linear 20 i lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB Lx po Table 4 4 Dynamic range of the microphone with 1 2 Microphone Preamplifier Type 2669 produced by a nominal Free field 1 2 Microphone Type 4190 at a Peak level of 154dB re 20uPa The microphone will maintain its charge up to a Peak level of 159dB re 20uPa Above this level the diaphragm and back plate short circuit If this occurs the microphone needs one or two minutes to recharge before it is ready to measure validly We recommend not to expose Free field 1 2 Microphone Type 4190 to levels higher than 159dB Peak 4 6 Equivalent Volume and Calibrator Load Volume Equivalent Volume For some applications it is practical to express the acoustic impedance of the micro phone diaphragm in terms of a complex equivalent volume This makes it easier to evaluate the effect of microphone loading on closed cavities or acoustic calibration couplers The real and imaginary parts of the equivalent volume shown in Fig 4 18 are in parallel They are calculated from a simple R L C series model of the microphone which gives the best overall approximation of the microphone s diaphragm imped ance The Models The following equivalent models are valid at 101 325 kPa 23 C and 50 RH BE 1376 12 Falcon Range of Microphone Products 4 17 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type
165. one 6 27 4193 pressure field microphone 7 30 Volume calibrator load 4188 prepolarized microphone 2 19 4189 prepolarized microphone 3 19 4190 free field microphone 4 18 4191 free field microphone 5 18 4192 pressure field microphone 6 18 4193 pressure field microphone 7 22 equivalent 4188 prepolarized microphone 2 19 4189 prepolarized microphone 3 18 4190 free field microphone 4 17 4191 free field microphone 5 17 4192 pressure field microphone 6 17 4193 pressure field microphone 7 20 Ww Windscreens 9 2 BE 1382 12 Falcon Range of Microphone Products Microphone Handbook Index 7 Index Index 8 Falcon Range of Microphone Products Briel amp Kj r Microphone Handbook
166. ophone s built in charge Therefore when mounting the microphone on a preamplifier the housings of the microphone and preamplifier must be connected before the centre pins make contact The de signs of Br el amp Kjar preamplifiers and sound level meters ensure this 2 9 Leakage Resistance The microphone s leakage resistance is greater than 5x10 0 at 90 RH and 23 C 2 10 Stability 2 10 1 Mechanical Stability The microphone s design with respect to mechanical stability is improved compared with traditional Bruel amp Kjar microphones The diaphragm damping ring is less sensitive to accidental force and the protection grid is significantly reinforced Therefore the microphone can withstand mechanical shocks better than traditional Bruel amp Kj r microphones The sensitivity change of the microphone is less than 0 1dB after a free fall of 1m onto a solid hardwood block re I EC 68 2 32 This improved mechanical stability makes Prepolarized Free field 1 2 Microphone Type 4188 well suited for surface mounting and for mounting in small couplers as no mechanical adaptor is required to protect the diaphragm damping ring The microphone can be supported by the diaphragm damping ring directly on the cou pler s surface Any force of less than 5Newtons will cause a change in sensitivity of less than 0 005dB This makes the microphone well suited for fitting in small plane wave couplers used for reciprocity calibration and any other sma
167. or Type 4228 Pistonphone INFLUENCE OF HUMIDITY 0 1 dB 100 RH VIBRATION SENSITIVITY 1000 Hz Typically 62 5 dB equivalent SPL for 1 m s axial acceleration MAGNETIC FIELD SENSITIVITY Typically 6 dB SPL for 80 A m 50 Hz field ESTIMATED LONG TERM STABILITY gt 1000 years dB dry air at 20 C gt 2 hours dB dry air at 150 C gt 40 years dB air at 20 C 90 RH gt 1 year dB air at 50 C 90 RH DIMENSIONS Diameter 13 2mm 0 52 in with grid 12 7 mm 0 50in without grid Height 17 6mm 0 68in with grid 16 3mm 0 64 in without grid Thread for preamplifier mounting 11 7 mm 60 UNS The data above are valid at 23 C 101 3kPa and 50 RH unless otherwise specified UA 0033 Electrostatic Actuator Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 3 Prepolarized Free field 1p Microphone Type 4189 Ordering Information Other Accessories UA 0308 Dehumidifier UA 0254 Set of 6 Windscreens UA 0237 90mm 3 5in UA 0469 Set of 6 Windscreens UA 0459 65 mm 2 6in BE1375 12 Falcon Range of Microphone Products 3 29 Microphone Handbook Chapter 3 Prepolarized Free field Tj Microphone Type 4189 Ordering Information 3 30 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 4 Free field 1 2 Microphone Type 4190 BE 1376 12 Falcon Range of Microphone Products Microphone
168. ortion characteristics of the microphone with 1 2 Microphone Preamplifier Type 2669 C and unload ed M The distortion is dependent on the capacitance parallel to the microphone It in creases with increasing capacitance The distortions given in Table 4 3 and Table 4 4 are valid for a parallel capacitance of 0 5pF The distortion is measured at 100Hz but can be assumed to be valid up to approximately 5kHz that is where the diaphragm displacement is predominantly stiffness controlled Distortion meas urement methods for higher frequencies are not available Maximum Sound Pressure L evel In general the microphone should not be exposed to sound pressure levels which produce voltages higher than the maximum input voltage specified for the connect ed preamplifier After an overload the preamplifier needs time to recover and dur ing this recovery period you cannot measure validly The maximum input voltage for most Bruel amp Kj r preamplifiers is 50V with a 130V supply This voltage is 4 16 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Equivalent Volume and Calibrator Load Volume Lower Limit Upper Limit 1 Hz bandwidth e OCtave is A weighted dB Linear 20 pa d lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB Table 4 3 Dynamic range of the microphone Lower Limit Upper Limit 1 Hz bandwidth Te
169. ponse dB 5 Tol Tol Tol TO 100 10k 100k Frequency Hz 9408965 Fig 3 3 Typical freefield response of the microphone with Protection Grid DB 3420 and the micro phone s specified tolerances The low frequency response is valid when the vent is exposed to the sound fidd The frequency response of Prepolarized F ree field 1 2 Microphone Type 4189 meets the requirements of IEC 651 Type 1 3 3 3 Actuator Response The microphone s frequency response is determined by adding corrections for the type of sound field to its actuator response obtained using Electrostatic Actuator BE1375 12 Falcon Range of Microphone Products Microphone Handbook Chapter 3 Prepolarized Free field Ap Microphone Type 4189 Frequency Response UA 0033 This is a reproducible and practical method for calibrating a microphone s frequency response Response dB 5 10 15 100 1k 10k 100 k Frequency Hz 940668e Fig 3 4 Typical actuator response magnitude measured with Electrostatic Actuator UA 0033 Response Degrees 0 45 90 135
170. quency Hz 9409496 Fig 3 18 Typical equivalent volume real and imaginary parts based on mathematical mode of microphone Model 1 C 20 324 x 10 2 m N L 305kg m R 77 x 109 Ns m where C acoustic diaphragm compliance L acoustic diaphragm mass R acoustic diaphragm damping resistance Model 2 Vig 46 mm fo 16kHz Q 0 4 where Vic low frequency volume fg diaphragm resonance frequency Q quality factor Calibrator Load Volume When the microphone with its protection grid is inserted into the coupler of a calibrator it will load the calibrator by a volume of 260mm at 250Hz Load volume correction to Pistonphone Type 4228 Calibration Level with Adaptor DP 0776 0 00 dB BE 1375 12 Falcon Range of Microphone Products 3 19 Microphone Handbook Chapter 3 Prepolarized Free field Ape Microphone Type 4189 Capacitance 3 7 Capacitance Capacitance pF 20 18 16 12 10 The microphone s impedance is determined by its capacitance In addition the preamplifier s input resistance and capacitance load the microphone This loading determines the electrical lower limiting frequency and the capacitive input attenua tion However with modern preamplifiers this loading is very small and is included in the preamplifier gain G see section 3 2 2 Only in special cases with high capacitive loading does the fall in capacitance with frequency have to be taken into account
171. r ation can probably be detected using a sound level calibrator In many cases the damage can be seen by carefully inspecting the protection grid and diaphragm 3 2 Sensitivity 3 2 1 Open circuit Sensitivity The open circuit sensitivity is defined as the sensitivity of the microphone when not loaded by the input impedance of the connected preamplifier the termination is described in IEC 1094 2 The sensitivity is measured for the individual microphone at 251 2Hz and stated on the microphone s calibration chart see section 3 1 2 and data disk see section 3 1 3 The nominal sensitivity is shown in Table 3 2 Nominal open circuit sensitivity Accepted Deviation dB Table 3 2 Nominal open circuit sensitivity 3 2 2 Loaded Sensitivity When loaded by a preamplifier the sensitivity of the microphone is given by where Sc overall sensitivity of microphone and preamplifier combination So open drcuit sensitivity of microphone G voltage gain of microphone and preamplifier combination in dB With Microphone Preamplifier Type 2639 G 0 1dB With 1 2 Microphone Preamplifier Type 2669 G 0 25dB BE 1375 12 Falcon Range of Microphone Products 3 5 Microphone Handbook Chapter 3 Prepolarized F ree field Ape Microphone Type 4189 Frequency Response Example Loaded sensitivity of typical microphone with 1 2 Microphone Preamplifier Type 2669 Sc 26 3 0 25 26 55 dB 3 2 3 K factor Some types of B
172. r ing this recovery period you cannot measure validly The maximum input voltage for most Bruel amp Kj r preamplifiers is 50V with a 130V supply This voltage is 6 16 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 6 Pressure field 1p Microphone Type 4192 Equivalent Volume and Calibrator Load Volume Lower Limit Upper Limit 1 Hz bandwidth e OCtave nis A weighted dB Linear 20 pa d lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB Table 6 3 Dynamic range of the microphone Lower Limit Upper Limit 1 Hz bandwidth A octave m A weighted dB Linear 20 i d lt 3 distortion Max SPL Peak at 1 kHz dB at 1 kHz 20 kHz dB dB i 1 Table 6 4 Dynamic range of the microphone with 1 5 Microphone Preamplifier Type 2669 produced by a nominal Pressure field 1 2 Microphone Type 4192 at a Peak level of 166dB re 20uPa The microphone will maintain its charge up to a Peak level of 171dB re 20uPa Above this level the diaphragm and back plate short circuit If this occurs the microphone needs one or two minutes to recharge before it is ready to measure validly We recommend not to expose Pressure field 1 2 Microphone Type 4192 to levels higher than 171dB Peak 6 6 Equivalent Volume and Calibrator Load Volume Equivalent Volume For some applications it is practical to express the acoustic impedance of the micro phone diaphr
173. r Both limits are influenced by the preamplifier This section gives values for the microphone with and without a preamplifier Inherent Noise The microphone s inherent noise is due to thermal movements of the diaphragm These vary proportionally with the square root of the absolute temperature in K The inherent noise increases with increasing temperature With reference to 20 C the inherent noise changes by 0 5dB at 55 C and by 0 5dB at 12 C The maximum variation of this noise for different samples of Pressure field 1 2 Micro phone Type 4192 is 1dB Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 6 Pressure field oy Microphone Type 4192 Dynamic Range The preamplifier s effect on the inherent noise of the combined microphone and preamplifier depends on the sensitivity and capacitance of the microphone for 1 2 Microphone Preamplifier Type 2669 see Fig 6 16 and Chapter 8 Sound Pressure Level 30 re 20 uPa dB 25 20 A 10 Microphone and Preamplifier Combination Lot 1 Microphone Preamplifier MN 0 10 100 1k 10k 20k M P C Frequency Hz 940720e Fig6 16 l 3 octave band inherent noise spectrum The shaded bar graphs are the broad band 20Hz to 20 kHz noise levels and the white bar graphs the A waghted noise levels of the microphone M 1 2
174. r el amp Kj r instruments use the K factor correction factor or the Ko factor open circuit correction factor for calibration K 26 Sc 3 2 Ko 26 S 3 3 Example Correction factor for typical microphone with 1 2 Microphone Preamplifier Type 2669 K 26 26 55 0 55 qB Open circuit correction factor for typical microphone with 1 2 Microphone Preampli fier Type 2669 Ko 26 26 3 0 3 dB 3 3 Frequency Response 3 3 1 General In acoustic measurements there are three types of sound field e Free field e Pressure field e Diffuse field The microphone is optimized to have a flat frequency response in one of these sound fields This response is called the optimized response A microphone s re sponse in a diffuse field is equivalent to its random incidence response This section shows the microphone s typical free field pressure field and random incidence responses together with the microphone s typical actuator response ob tained using Electrostatic Actuator UA 0033 The low frequency response described in section 3 3 4 is common for all types of response 3 6 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 3 Prepolarized Free field 1 Microphone Type 4189 Frequency Response All frequency responses and correction curves are shown with a frequency resolu tion of 1 12 octave 3 3 2 Optimized Response 0 incidence Free field Response Res
175. ration chart Both are normalized to OdB at the reference frequency 251 2 Hz The exact reference frequency is 102 Hz re ISO 266 BE1378 12 Falcon Range of Microphone Products 6 3 Microphone Handbook Chapter 6 Pressure field ty Microphone Type 4192 Introduction The lower curve on the calibration chart is the individual microphone s open circuit pressure field response This response is the optimized response for the Pressure field 1 Microphone Type 4192 The upper curve on the calibration chart is the random incidence response Both curves are determined by adding the relevant correction curve to the individu al actuator response measured with Electrostatic Actuator UA 0033 The individual microphone s electrostatic actuator response is also available on the data disk The dotted part of the curve is the typical low frequency response Each micro phone s individual lower limiting frequency is measured to ensure that it is within the specified tolerances see Fig 6 3 6 1 3 Data Disk The 31 2 data disk supplied with each microphone supplements the calibration chart It contains individual calibration data and correction curves see Table 6 1 with a frequency resolution of 1 12 octave as comma separated ASCII text files un der the X DATA directory SAHHHHHHEBKM Sensitivity calibration 251 2Hz AIHHHHHHI BKM Actuator response 200 Hz 22 kHz PAHHHHHEBEBKRD Pressure field response 1Hz 22kHz
176. ree field microphone 5 5 4192 pressure field microphone 6 5 4193 pressure field microphone 7 6 Long term stability 4188 prepolarized microphone 2 22 4189 prepolarized microphone 3 22 4190 free field microphone 4 22 4191 free field microphone 5 22 4192 pressure field microphone 6 22 4193 pressure field microphone 7 25 Low frequency Pressure field 1 2 Microphone Type4193 7 1 Low frequency response 4188 prepolarized microphone 2 7 4189 prepolarized microphone 3 8 4190 free field microphone 4 8 4191 free field microphone 5 8 4192 pressure field microphone 6 8 4193 pressure field microphone 7 10 M Magnetic field 2669 preamplifier 8 9 4188 prepolarized microphone 2 27 4189 prepolarized microphone 3 27 4190 free field microphone 4 27 4191 free field microphone 5 27 4192 pressure field microphone 6 27 4193 pressure field microphone 7 30 Maximum output 2669 preamplifier 8 6 Maximum Sound Pressure Level 4188 prepolarized microphone 2 18 4189 prepolarized microphone 3 17 4190 free field microphone 4 16 4191 free field microphone 5 16 4192 pressure field microphone 6 16 4193 pressure field microphone 7 20 Mechanical shock stability 4188 prepolarized microphone 2 21 4189 prepolarized microphone 3 21 4190 free field microphone 4 21 4191 free field microphone 5 21 4192 pressure field microphone 6 21 4193 pressure field microphone 7 24 Microphone accessories 9 2 adaptor 8 12 Microphone Preamplifier 1 2
177. response for Free field 1 2 Microphone Type 4191 d Corrections for Free field 2 Microphone Type 4191 These text files can be viewed on Microsoft Windows using the Br el amp Kj r Microphone Viewer program BK MIC EXE supplied on the disk They can also be accessed by a suitable spreadsheet for further processing or printing Bruel amp Kj r Microphone Viewer must be installed before use see section 1 3 5 5 4 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 5 Free field Microphone Type 4191 Sensitivity 5 1 4 Recommended Recalibration Interval With normal handling of the microphone and any associated instrument Bruel amp Kj r recommends that the microphone be recalibrated every 2 years Free field 1 2 Microphone Type 4191 is very stable over this period see section 5 10 to section 5 12 Improper handling is by far the most likely cause of change in the microphone s properties Any damage which causes improper operation can probably be detected using a sound level calibrator In many cases the damage can be seen by carefully inspecting the protection grid and diaphragm 5 2 Sensitivity 5 2 1 Open circuit Sensitivity The open circuit sensitivity is defined as the sensitivity of the microphone when not loaded by the input impedance of the connected preamplifier the termination is described in IEC 1094 2 The sensitivity is measured for the individual microphone
178. ressure applied to the dia phragm In special cases where there is a risk of preamplifer overload or there are long cables to be driven choose a lower voltage This will cause a lower sensitivity see Fig 6 20 and a change in the frequency response see Fig 6 21 BE1378 12 Falcon Range of Microphone Products 6 19 Microphone Handbook Chapter 6 Pressure field Lp Microphone Type 4192 Polarization Voltage Response dB 5 10 20 50 100 200 500 Po Voltage V 9406836 Fig 6 20 Variation in sensitivity at 250Hz as a function of po larization voltage relative to the sensitivity with a polar ization voltage of 200V Response dB 2 5 2 5 100 1k Hz 10k 100k Frequency Hz 940608e Fig 6 21 Effect of polarization voltage on frequency response The curves show the difference from the response with a polarization voltage of 200V normalised at 250 Hz 6 20 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 6 Pressure field T Microphone Type 4192 Leakage Resistance 6 9 Leakage Resistance To maintain the correct polarization voltage on the microphone the microphone s leakage resistance must be at le
179. ring Information Other Accessories UA 0254 Set of 6 Windscreens UA 0237 90mm 3 5in UA 0469 Set of 6 Windscreens UA 0459 65 mm 2 6in BE 1377 12 Falcon Range of Microphone Products 5 29 Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Ordering Information 5 30 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 6 Pressure field 1 2 Microphone Type 4192 BE 1378 12 Falcon Range of Microphone Products 6 1 Microphone Handbook Chapter 6 Pressure field ty Microphone Type 4192 Introduction 6 1 Introduction 6 1 1 Description Fig 6 1 Pressure field 1 2 Microphone Type 4192 with Protection Grid DB 3421 included Pressure field 1 2 Microphone Type 4192 is an externally polarized 1 2 pressure field microphone for sound measurements requiring random incidence response in accordance with the requirements of ANSI S 1 4 Type 1 or for coupler measure ments for example in connection with telephone and hearing aid testing Further more it also satisfies the requirements of ANSI S 1 12 Type M With its low inherent noise and frequency range from 3 15 Hz to 20kHz it is very well suited for a wide range of precision audio frequency sound measurements The microphone requires a polarization voltage of 200 V provided by the instrument or analyzer powering the associated preamplifier This rugged microphone is built to ensure high
180. rophone Products Br el amp Kj r Microphone Handbook Chapter 5 Free field 4 2 Microphone Type 4191 BE 1377 12 Falcon Range of Microphone Products Microphone Handbook 5 1 Chapter 5 Free field ty Microphone Type 4191 Introduction 5 1 Introduction 5 1 1 Description Fig 5 1 Freefield 1 2 Microphone Type 4191 with Protection Grid DB 3421 included Free field 1 2 Microphone Type 4191 is an externally polarized microphone for gen eral sound measurements and for standardized noise measurements in accordance with the requirements of IEC 651 Type 0 and Type 1 With its low inherent noise and frequency range from 3 15 Hz to 40 kHz it is very well suited for a wide range of precision audio frequency sound measurements and electro acoustic measure ments on loudspeakers and microphones The microphone requires a polarization voltage of 200V provided by the instrument or analyzer powering the associated preamplifier This rugged microphone is built to ensure high stability under a variety of condi tions For example the stainless steel alloy diaphragm withstands polluted industri al environments The diaphragm clamping ring is firmly secured to ensure the microphones reliability even when the microphone is used without its protection grid When the microphone is used without its protection grid it can be easily flush mounted or inserted into closed volumes as it can be supported by the dia phragm c
181. rtionally with the square root of the absolute temperature in K The inherent noise increases with increasing temperature With reference to 20 C the inherent noise changes by 0 5dB at 55 C and by 0 5dB at 12 C The maximum variation of this noise for different samples of Free field 1 2 Microphone Type 4191 is x 1dB 5 14 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 5 Free field Ton Microphone Type 4191 Dynamic Range The preamplifier s effect on the inherent noise of the combined microphone and preamplifier depends on the sensitivity and capacitance of the microphone for 1 2 Microphone Preamplifier Type 2669 see Fig 5 16 and Chapter 8 Sound Pressure Level re 20 uPa dB modo 7 Preamplifier Frequency Hz 940719e Fig 5 16 Y 3 octave band inherent noise spectrum The shaded bar graphs are the broad band 20Hz to 40 kHz noise levels and the white bar graphs the A weghted noise levels of the microphone M 1 2 Microphone Preamplifier Type 2669 P and microphone and pream plifier combination C BE 1377 12 Falcon Range of Microphone Products 5 15 Microphone Handbook Chapter 5 Free field ty Microphone Type 4191 Dynamic Range Distortion The distortion is determined mainly by the microphone but at the highe
182. st opera tion levels the preamplifier also contributes to the distortion see Fig 5 17 Distortion 10 gnd Harmonic 0 1 0 01 135 145 SPL dB 155 165 940499e Fig 5 17 Typical distorion characteristics of the microphone with 1 2 Microphone Preamplifier Type 2669 C and unload ed M The distortion is dependent on the capacitance parallel to the microphone It in creases with increasing capacitance The distortions given in Table 5 3 and Table 5 4 are valid for a parallel capacitance of O 5pF The distortion is measured at 100Hz but can be assumed to be valid up to approximately 5kHz that is where the diaphragm displacement is predominantly stiffness controlled Distortion meas urement methods for higher frequencies are not available Maximum Sound Pressure L evel In general the microphone should not be exposed to sound pressure levels which produce voltages higher than the maximum input voltage specified for the connect ed preamplifier After an overload the preamplifier needs time to recover and dur ing this recovery period you cannot measure validly The maximum input voltage for most Bruel amp Kj r preamplifiers is 50V with a 130V supply This voltage is 5 16 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 5 Free field i Microphone Type 4191 Equivalent Volum
183. stability under a variety of condi tions For example the stainless steel alloy diaphragm withstands polluted industri al environments The diaphragm damping ring is firmly secured to ensure the microphones reliability even when the microphone is used without its protection grid When the microphone is used without its protection grid it can be easily flush mounted or inserted into closed volumes as it can be supported by the dia phragm damping ring provided that a force of less than 5Newtons is applied The microphone is supplied with individual calibration data on a calibration chart and on a 31 2 data disk in a case This case can also contain a 1 2 Microphone Preamplifier Type 2669 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 6 Pressure field Microphone Type 4192 Introduction 6 1 2 The Calibration Chart Each microphone is supplied with an individual calibration chart see Fig 6 2 which gives the microphone s open circuit sensitivity polarized capacitance and pressure field and random incidence frequency responses kurve skal slutte her Pressure field 7 1 2 Microphone Type 4192 Bruel amp Kj r Calibration Chart Serial No 419205A Open circuit Sensitivity So 38 6 dB re 1V Pa aee Equivalent to 11 8 mviPa t j Uncertainty 95 confidence level 0 2 dB at LO 2 Capacitance 18 4 pF Valid At Temperature 23 T Ambient Static Pressure 101 3 kPa
184. sure field microphone 6 4 4193 pressure field microphone 7 4 Distortion 2669 preamplifier 8 6 4188 prepolarized microphone 2 18 4189 prepolarized microphone 3 17 4190 free field microphone 4 16 4191 free field microphone 5 16 4192 pressure field microphone 6 16 4193 pressure field microphone 7 18 Dynamic range 2669 preamplifier 8 5 4188 prepolarized microphone 2 16 4189 prepolarized microphone 3 15 4190 free field microphone 4 14 4191 free field microphone 5 14 4192 pressure field microphone 6 14 4193 pressure field microphone 7 16 E Electromagnetic compatibility 8 9 EMC 8 9 Equivalent volume 4188 prepolarized microphone 2 19 4189 prepolarized microphone 3 18 4190 free field microphone 4 17 4191 free field microphone 5 17 4192 pressure field microphone 6 17 4193 pressure field microphone 7 20 Extension cable 8 11 9 2 Index 2 Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Index F Free field 1 2 Microphone Type 4190 4 1 Free field 1 2 Microphone Type 4191 5 1 Free field frequency response 4188 prepolarized microphone 2 8 4189 prepolarized microphone 3 9 4190 free field microphone 4 9 4191 free field microphone 5 9 4192 pressure field microphone 6 9 4193 pressure field microphone 7 10 Frequency response 2669 preamplifier 8 4 actuator 4188 prepolarized microphone 2 6 4189 prepolarized microphone 3 7 4190 free field microphone 4 7 4191 free field m
185. surements there are three types of sound field e Free field e Pressure field e Diffuse field The microphone is optimized to have a flat frequency response in one of these sound fields This response is called the optimized response A microphone s re sponse in a diffuse field is equivalent to its random incidence response This section shows the microphone s typical free field pressure field and random incidence responses together with the microphone s typical actuator response ob tained using Electrostatic Actuator UA 0033 The low frequency response described in section 5 3 4 is common for all types of response 5 6 Falcon Range of Microphone Products Briel amp Kj r Microphone Handbook Chapter 5 Free field lp Microphone Type 4191 Frequency Response All frequency responses and correction curves are shown with a frequency resolu tion of 1 12 octave 5 3 2 Optimized Response 0 incidence Free field Response Response dB 5 Tol Tol Tol Tol 1 10 100 1k 10k 100 k Frequency Hz S408 7o Fig 5 3 Typical free field response of the microphone with Protection Grid DB 3421 and the micro phone s specified tolerances The low frequency response is valid when the vent is exposed to the sound fidd The frequency response of Free field 1
186. t of Temperature Response dB 1 5 0 5 10 C 0 0 50 C 205 1 5 500 Hz 1k 10k Frequency Hz 50k 940773e Fig 3 21 Typical variation in actuator response normalized at 250Hz as a function of temperature relative to the re sponse at 20 C see Fig 3 4 Response dB 1 5 0 5 10 C 0 0 0 5 1 5 500 Hz 1k 10k Frequency Hz 50k 940807 1e Fig 3 22 Typical variation in 0 incidence free fid d response with Protection Grid DB 3420 normalized at 250Hz as a function of temperature relative to the response at 20 C see Fig 3 7 3 24 Falcon Range of Microphone Products Microphone Handbook Br el amp Kj r Chapter 3 Prepolarized Free field Tor Microphone Type 4189 Effect of Ambient Pressure 3 12 Effect of Ambient Pressure The microphones sensitivity and frequency response are affected by variations in the ambient pressure This is due to changes in air stiffness in the cavity behind the diaphragm and changes in air mass in the small gap between the diaphragm and the back plate The effects are shown in Fig 3 23 to Fig 3 25 The typical pressure coefficient at 250Hz for Prepolarized Free f
187. tance it introduces has the effect of reducing the lower cut off frequency of the preamplifier in the case of 1 2 Microphone Preamplifier Type 2669 down to 0 1Hz The microphone requires a polarization voltage of 200 V provided by the instrument or analyzer powering the associated preamplifier This rugged microphone is built to ensure high stability under a variety of condi tions For example the stainless steel alloy diaphragm withstands polluted industri al environments The diaphragm damping ring is firmly secured to ensure the microphones reliability even when the microphone is used without its protection grid When the microphone is used without its protection grid it can be easily Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field oy Microphone T ype 4193 Introduction flush mounted or inserted into closed volumes as it can be supported by the dia phragm clamping ring provided that a force of less than 5Newtons is applied The microphone is supplied with individual calibration data on a calibration chart and on a 31 2 data disk in a case This case can also contain a 1 2 Microphone Preamplifier Type 2669 7 1 2 The Calibration Chart Each microphone is supplied with an individual calibration chart see Fig 7 2 which gives the microphone s open circuit sensitivity polarized capacitance cut off frequency and pressure field and random incidence
188. tatic Actuator UA 0033 If the polarization voltage is positive as it is with Bruel amp Kj r instruments the output voltage is negative for a positive pressure applied to the diaphragm 6 3 4 Low frequency Response The low frequency response see Fig 6 3 is the typical response with the vent ex posed to the sound field If the vent is not exposed to the sound field the sensitivity increases from OdB at the reference frequency 251 2 Hz to approximately 0 2dB at 1Hz 6 8 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 6 Pressure field v Microphone Type 4192 Frequency Response For applications where the vent is not exposed to the sound field take care to ensure proper static pressure equalization to prevent static displacement of the diaphragm The microphone s low frequency response is common for all types of sound field The microphone s lower limiting frequency 3dB is between 1 and 2Hz with the vent exposed to the sound field This is measured during production to ensure that specifications are fulfilled 6 3 5 Free field Response The microphone s free field correction curves are shown in Fig 6 6 and Fig 6 8 These corrections are added to the microphone s actuator response obtained using Elecrostatic Actuator UA 0033 in order to determine the free field response at any angle of incidence The typical free field response at 0 incidence with and without the protection gr
189. temperature relative to the response at 20 C see Fig 5 7 over the temperature range defined by IEC651 5 12 Effect of Ambient Pressure The microphones sensitivity and frequency response are affected by variations in the ambient pressure This is due to changes in air stiffness in the cavity behind the diaphragm and changes in air mass in the small gap between the diaphragm and the back plate The effects are shown in Fig 5 26 to Fig 5 28 BE 1377 12 Falcon Range of Microphone Products 5 25 Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Effect of Ambient Pressure The typical pressure coefficient at 250Hz for Freefield 1 2 Microphone Type 4191 is 0 007 dB kPa well within the 0 03dB kPa limits required for Type 0 and Type 1 sound level meters by IEC 651 Correction dB 3 40kPa change 20kPa z7 change 10kPa change 1 10k Frequency Hz 50k 940764e Fig 5 26 Typical variation in frequency response normalized at 250 Hz from that at 101 3kPa as a function of changein ambient pressure Response dB 30 20 v c 7 0 id X Bis ee b NS d zi X ndn AN j 2 a EN 20 10k Frequency Hz 50k 500 1k
190. th a 130V supply This voltage is produced by a nominal Low frequency Pressure field 1 2 Microphone Type 4193 at a Peak level of 166dB re 20uPa The microphone will maintain its charge up to a Peak level of 171dB re 20uPa Above this level the diaphragm and back plate short circuit If this occurs the microphone needs one or two minutes to recharge before it is ready to measure validly We recommend not to expose Low frequency Pressure field 1 2 Microphone Type 4193 to levels higher than 171dB Peak 7 6 Equivalent Volume and Calibrator Load Volume Equivalent Volume For some applications it is practical to express the acoustic impedance of the micro phone diaphragm in terms of a complex equivalent volume This makes it easier to evaluate the effect of microphone loading on dosed cavities or acoustic calibration couplers 7 20 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 7 Low frequency Pressure field 1p Microphone Type 4193 Equivalent Volume and Calibrator Load Volume Volume mm 12 10 8 The real and imaginary parts of the equivalent volume shown in Fig 7 19 are in parallel They are calculated from a simple R L C series model of the microphone which gives the best overall approximation of the microphone s diaphragm imped ance 100 10k 100k I o Frequency Hz s 94
191. the pressure field response The typical pressure field response is shown in Fig 4 13 In practice the pressure field response is often regarded as being equal to the actuator response as the difference between them is small compared to the uncer tainty related to many types of measurement Correction dB 4 100 1k 10k 100 k Frequency Hz 940866e Fig 4 12 Pressurefield correction for the microphone 4 12 Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 4 Free field 1 2 Microphone Type 4190 Directional Characteristics Response dB 5 20 100 10k 100k 940870e Frequency Hz Fig 4 13 Typical pressure field response for the microphone 4 4 Directional Characteristics Typical directional characteristics are given in Fig 4 14 and Fig 4 15 The character istics are normalised relative to the 0 response Note The non symmetrical responses are at frequencies outside the microphone s nominal operating range 25 and 31 5 kHz AMI ll Wht atu gL VA L CAU 207E 25 Srog Mlle ARRIERE T ANM 1 WA MUTARE I WA WU i STEEL lli MIU a 0 06 CTE TS eg HH
192. traditional Bruel amp Kjaer microphones Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 7 Low frequency Pressure field 1p Microphone Type 4193 Stability The sensitivity change of the microphone is less than O 1dB after a free fall of 1m onto a solid hardwood block re IEC 68 2 32 This improved mechanical stability makes Low frequency Pressure field 1 2 Micro phone Type 4193 well suited for surface mounting and for mounting in small cou plers as no mechanical adaptor is required to protect the diaphragm clamping ring The microphone can be supported by the diaphragm damping ring directly on the coupler s surface Any force of less than 5Newtons will cause a change in sensitivity of less than 0 005dB This makes the microphone well suited for fitting in small plane wave couplers used for reciprocity calibration and any other small coupler with a well defined volume 7 10 2 High temperature Stability The diaphragm is made of a stainless steel alloy The alloy has been carefully selected and is very resistant to heat This means that the diaphragm tension and therefore the sensitivity remain the same even after several hours operation at high temperature The microphone has been tested at temperatures up to 300 C Below 170 C no changes occur At 170 C the sensitivity can be permanently changed within the first 10hours by less than 0 025 dB After this the sensitivity can be per
193. ume correction to Pistonphone Type 4228 Calibration Level with Adaptor DP 0776 40 02 dB 6 18 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 6 Pressure field Microphone Type 4192 Capacitance 6 7 Capacitance Capacitance pF 20 The microphone s impedance is determined by its polarized capacitance In addition the preamplifier s input resistance and capacitance load the microphone This load ing determines the electrical lower limiting frequency and the capacitive input at tenuation However with modern preamplifiers this loading is very small and is induded in the preamplifier gain G see section 6 2 2 Only in special cases with high capacitive loading does the fall in capacitance with frequency have to be taken into account 250 V 200 V 150 V 28 V 1k Hz 10k 5 H 100k requency Hz 940605e Fig 6 19 Variation of capacitance with polarization voltage and frequency Typical capacitance at 250 Hz 18 pF The capacitance is individually calibrated and stated on the calibration chart 6 8 Polarization Voltage Generally a microphone is operated at its nominal polarization voltage For Pres sure field 1 2 Microphone Type 4192 this is 200V As this polarization voltage is positive the output voltage is negative for a positive p
194. ured with Electrostatic Actuator UA 0033 This response is used to determine free field responses at angles of incidence other than 0 and responses in other types of sound field The individual microphone s electrostatic actuator response is also available on the data disk The dotted part of the curve is the typical low frequency response Each micro phone s individual lower limiting frequency is measured to ensure that it is within the specified tolerances see Fig 4 3 4 1 3 Data Disk The 31 2 data disk supplied with each microphone supplements the calibration chart It contains individual calibration data and correction curves see Table 4 1 with a frequency resolution of 1 12 octave as comma separated ASCII text files un der the DATA directory SAHHHHEHHEBKM Sensitivity calibration 251 2Hz AIIBHHHHEBKME Actuator response 200 Hz 22 kHz FA4HHHHHHEBKRD Free field response 1Hz 22kHz 4190L BKT Low frequency response 1Hz 190 Hz Table4 1 Calibration data and corrections contained on the data disk Note Z4ABHHBE is the micro phone s serial number a Individual calibration data measured b Low frequency response combined with actuator response and free field corrections c Typical response for Free field 1 2 Microphone Type 4190 d Corrections for Free field 2 Microphone Type 4190 These text files can be viewed on Microsoft Windows using the Br el amp Kj r Microphone Viewer program BK MIC EX
195. ut its protection grid When the microphone is used without its protection grid it can be easily flush mounted or inserted into closed volumes as it can be supported by the dia phragm damping ring provided that a force of less than 5Newtons is applied It is supplied with a calibration chart Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 2 Prepolarized Free field Microphone Type 4188 Introduction 2 1 2 The Calibration Chart Each microphone is supplied with an individual calibration chart see Fig 2 2 which gives the microphone s open circuit pressure sensitivity together with the typical capacitance and free field and random incidence frequency responses When these are combined with the microphone s typical data supplied in this chapter the individual microphone s response under various conditions can be determined Prepolarized Condenser Microphone Cartridge Type 4188 Caution Static electricity discharge directly on the centre terminal may damage the prepolarization of the Serial No 1740259 Open circuit Pressure Sensitivity at 1013 hPa 23 C and 50 RH 30 2 dB re 1 V Pa or 30 9 mV Pa Frequency 1000Hz Capacitance 12pF typical than the pressure sensitivity cartridge Therefore ensure that the housing of the cartridge makes contact before the centre terminal Sensitivity The loaded sensitivity is typically 0 05 dB lower than the sensitivity stated The rando
196. valent Volume and Calibrator Load Volume seseeeeeeeee 2 19 2 Br ense M 2 20 2 8 Polarization so MD 2 20 2 9 Legkage RSISESICB ccce as rre peser crece see p peek ex TRE E ERR A 2 21 2 10 cri 2 21 241 ESE OFT SAWCT abu Ge cie emperor tercero et ere etae eeu M2 a S REEF De CEU eR esee ERE ENO 2 22 2 12 Efed o Ambient arii M A1 2 25 2 13 psu ilf lee rr 2 26 2 14 E dec or Vibra ON utin can tera EY eue repe euw es nue Fen aesc e ads cavascecntestye tu AERA TERR D IUE 2 27 2 15 E ted or Megueticf Heli ose GG iin inside e RR ERE RAI E MR ER PERS ER 2 27 2 16 Electromagnetic Compati Bi VG suec cede ener oett rare n reae penetra cdedecdacaacnete set 2 27 2 17 Spedfications Overview p E 2 28 2 18 Ordering mnformmetlet secre o onere dede ir te e dede eR HERE exer nara n tute 2 28 3 Prepolarized Free field d Microphone Type 4189 3 3 3 1 Hnmuecioqu EE 3 2 3 2 S A E E E A A 3 5 3 3 NE SBN v e a a aaa a a aE aaa aaa Ea 3 6 3 4 Direccional Characberi Stigs cesi einen en enne terna nno rnnt ra Caah iaeia AEAN EAEE 3 14 3 5 Dynami Range eroii a e DETTQE LTEM 3 15 36 Equivalent Volume and Calibrator Load Volume sseeeeeeene 3 18 3 7 Lap EE 3 20 3 8 Polarization VOOR 3 20 3 9 L akag RESISEAICS 6 5 cccccscsssscscccctasscdecessiccnenenseesesdachssstncedabentasevensc
197. value can be given for the microphone s long term stability but measured changes at high temperatures indicate that Pressure field 1 2 Micro phone Type 4192 is more than 10 times more stable than traditional Br el amp Kjaer microphones This indicates typical changes of less than 1dB in 5000 years 6 11 Effect of Temperature By careful selection of materials optimization of the design and artificial ageing the effect of temperature has been made to be very low The microphone has been designed to operate at temperatures from 30 to 300 C When the microphone is subjected to temperatures above 200 C it may be discol oured but its functionality will remain unaffected See section 6 10 2 for permanent changes in sensitivity at temperatures above 170 C Falcon Range of Microphone Products Br el amp Kjaer Microphone Handbook Chapter 6 Pressure field n Microphone Type 4192 Effect of Temperature The reversible changes are shown in Fig 6 22 as a change in sensitivity and in Fig 6 23 to Fig 6 25 as changes in the frequency response normalized at 250Hz Response dB oe 0 0 0 5 2 0 50 0 50 100 150 200 250 300 Temperature C 940876e Fig 6 22 Typical variation in sensitivity at 250Hz as a function of temperature relative to the sensitivity at 20 C Temperature Coefficient 250 Hz 0 002 dB C typical for the range 10 to 50 C BE1378 12 Falcon
198. verall approximation of the microphone s diaphragm imped ance The Models The following equivalent models are valid at 101 325 kPa 23 C and 50 RH BE 1377 12 Falcon Range of Microphone Products 5 17 Microphone Handbook Chapter 5 Free field Ty Microphone Type 4191 Equivalent Volume and Calibrator Load Volume Volume mm 12 L LLLI 100 1k 10k Frequency Hz 100k 940947e Fig 5 18 Typical equivalent volume real and imaginary parts based on mathematical moda of microphone Model 1 C 20 082 x 1012 m N L 253kg m R 278x 10 Ns m where C acoustic diaphragm compliance L acoustic diaphragm mass R acoustic diaphragm damping resistance Model 2 Vip 11 6mm fo 35kHz Q 0 2 where Vie low frequency volume fg diaphragm resonance frequency Q quality factor Calibrator Load Volume When the microphone with its protection grid is inserted into the coupler of a calibrator it will load the calibrator by a volume of 190 mm at 250Hz Load volume correction to Pistonphone Type 4228 Calibration Level with Adaptor DP 0776 40 02 dB 5 18 Falcon Range of Microphone Products Br el amp Kj r Microphone Handbook Chapter 5 Free field Microphone Type 4191 Capacitance 5 7 Capacitance Capacitance pF 20 The microphone s impedance is determined by its polarized
199. vesssstunsesndeobensbessts 3 21 3 10 PRAM s 3 21 BE1373 12 Falcon Range of Microphone Products 0 3 Microphone Handbook Contents 3 11 Emet of Wir SOE CMM 3 22 3 12 pex Ambient PreTre ai aaa EEE iaaa RAR 3 25 3 13 cup ead pui ark ps E 3 26 3 14 AUER E e M 3 27 3 15 Effecto Magnetic dir E 3 27 3 16 El amp ctromagnetie E ompatl Di Ey coeno cuit sa artt etae euer tapa sa te peer E eret AARAA 3 27 3 17 SR UT MEL pcd p pM E 3 28 3 18 Ordering Inor PANG IMP 3 28 4 Free field E Microphone Type 4190 4 1 4 1 PET OCONEE gen 4 2 4 2 SSN MY M E T 4 5 4 3 FPN RESPONSE RM 4 6 4 4 Directional Characteristics m 4 13 4 5 Dynami C RANE M 4 14 4 6 Equivalent Volume and Calibrator Load Volume sese 4 17 4 7 Cpecspcpsc P 4 19 4 8 Polarization Voltage IEEE 4 19 4 9 LGA callis acsc ans iccsedscanesssectessdentinsecesnvesetiesssausdsscecedasesavsbbensnwedadvocselseresests 4 21 4 10 erp aces carcass E 4 21 4 11 cad gi u p nasb E 4 22 4 12 Effect or Ambient Pressure etre nnn nana nbn n nre Rae corona SAN 4 25 4 13 Effect of Munay 4 27 4 14 axi deri ecien aa aa a AREENAN 4 27 4 15 Ereto a SGU CF 1 T 4 27 4 16 Eledromagnetic Compatto y E 4 28 4 17 Specifications OVA VON 4 28 4 18 Ordering
200. y The open circuit sensitivity is defined as the sensitivity of the microphone when not loaded by the input impedance of the connected preamplifier the termination is described in IEC 1094 2 The sensitivity is measured for the individual microphone at 251 2 Hz and stated on the microphone s calibration chart see section 7 1 2 and BE1379 12 Falcon Range of Microphone Products 7 5 Microphone Handbook Chapter 7 Low frequency Pressure field ion Microphone T ype 4193 Sensitivity data disk see section 7 1 3 The nominal sensitivity for a microphone without Adaptor UC 0211 fitted is shown in Table 7 2 Nominal open circuit sensitivity Accepted Deviation dB Table 7 2 Nominal open circuit sensitivity 7 2 2 Loaded Sensitivity When loaded by a preamplifier the sensitivity of the microphone is given by where Sc overall sensitivity of microphone and preamplifier combination So open circuit sensitivity of microphone G voltage gain of microphone and preamplifier combination in dB With Microphone Preamplifier Type 2639 G O 1dB With 1 2 Microphone Preamplifier Type 2669 G 0 2dB With 1 2 Microphone Preamplifier Type 2669 and Adaptor UC 0211 G 16 5 dB 1dB Example Loaded sensitivity of typical microphone with 1 2 Microphone Preamplifier Type 2669 Sc 38 3 0 2 38 5 dB Loaded sensitivity of typical microphone with 1 2 Microphone Preamplifier Type 2669 and Adaptor UC 0211
201. ypical for the range 10 to 50 C 4 18 Ordering Information Preamplifier Type 2669 1 Microphone Preamplifier Calibration Equipment Type 4231 Sound Level Calibrator Type 4226 Multifunction Acoustic Calibrator Type 4228 Pistonphone PRESSURE COEFFICIENT 250 Hz 0 010 dB kPa typical INFLUENCE OF HUMIDITY 0 1 dB 100 6 RH VIBRATION SENSITIVITY 1000 Hz Typically 62 5 dB equivalent SPL for 1 m s axial acceleration MAGNETIC FIELD SENSITIVITY Typically 4dB SPL for 80 A m 50 Hz field ESTIMATED LONG TERM STABILITY 1000 years dB at 20 C 2100 hours dB at 150 C DIMENSIONS Diameter 13 2 mm 0 52in with grid 12 7 mm 0 50 in without grid 17 6 mm 0 68 in with grid 16 3mm 0 64 in without grid Thread for preamplifier mounting 11 7 mm 60 UNS Height The data above are valid at 23 C 101 3 kPa and 5096 RH unless otherwise specified UA 0033 Electrostatic Actuator Falcon Range of Microphone Products Microphone Handbook Br el amp Kjaer Chapter 4 Free field 1 2 Microphone Type 4190 Ordering Information Other Accessories UA 0308 Dehumidifier UA 0254 Set of 6 Windscreens UA 0237 90mm 3 5in UA 0469 Set of 6 Windscreens UA 0459 65 mm 2 6in BE 1376 12 Falcon Range of Microphone Products 4 29 Microphone Handbook Chapter 4 Free field 1 5 Microphone Type 4190 Ordering Information 4 30 Falcon Range of Mic
202. ypically 0 4dB which stabilises after one hour OPERATING HUMIDITY RANGE 0 to 100 RH without condensation STORAGE TEMPERATURE 30 to 70 C 22 to 158 F TEMPERATURE COEFFICIENT 250 Hz 0 002dB C typical for the range 10 to 50 C ATTENUATION 16dB CAPACITANCE 100 pF typical PRESSURE COEFFICIENT 250 Hz 0 005 dB kPa typical INFLUENCE OF HUMIDITY 1000 years dB at 20 C 0 001 dB 100 RH VIBRATION SENSITIVITY 1000 Hz Typically 65 5 dB equivalent SPL for 1 m s axial acceleration MAGNETIC FIELD SENSITIVITY Typically 16 dB SPL for 80 A m 50 Hz field ESTIMATED LONG TERM STABILITY 2100 hours dB at 150 C DIMENSIONS Diameter 13 2 mm 0 52 in with grid 12 7 mm 0 50 in without grid 13 5 mm 0 54 in with grid 12 6mm 0 50 in without grid Thread for preamplifier mounting 11 7 mm 60 UNS Height The data above are valid at 23 C 101 3 kPa and 5096 RH unless otherwise specified DIMENSIONS Diameter 12 7 mm 0 50 in Height 14 1 mm 0 56in Thread for preamplifier and microphone mount ing 11 7 mm 60 UNS BE1379 12 Falcon Range of Microphone Products Microphone Handbook Chapter 7 Low frequency Pressure field n Microphone T ype 4193 Ordering Information 7 18 Ordering Information Preamplifier Type 2669 1 2 Microphone Preamplifier Calibration Equipment Type 4231 Sound Level Calibrator Type 4226 Multi

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