Altec Lansing 938-8AE User's Manual
Contents
1. DESCRIPTION The Altec Lansing 938 multi purpose loudspeaker systems are both compact and versatile They were designed to be used as high level stage monitors in portable sound reinforcement and can also be used as a small full range system in churches or night clubs or for reinforcement installation in any small to medium room The 938 may be placed at 90 50 or 30 angles referenced to floor plane mounting surface The reversible grille permits a right side up orientation regardless of the speaker s position The 938 uses an upgraded version of the Altec Lansing 604 long recognized for uniform frequency response and high efficiency with low and high frequency elements mounted coaxially to produce a single point source of sound New materials have been used in the low and high frequency voice coils 938 8AD 938 8AE LOUDSPEAKER SYSTEM which allow the 938 to handle large power amp lifier outputs The dividing network is designed with 12 dB per octave slopes for a smooth and gradual transition at crossover and has adjustable attenuation at high frequencies The enclosure is constructed of 34 birch plywood and is finished in a black texture surface poly urethane paint with a black grille The 938 also features recessed carrying handles and durable metal corner guards to protect the cabinet during handling and set up In addition convenient tee nut mounting points are provided to aid in hanging the system in a permane2. 437 SYNSS3Yd ANNOS CENTER OF GRAVITY 4 20 A 6 1 16 51 cm FLAT WASHER l B 11 4 28 57 cm Figure 14 Mounting Data MOUNTING INFORMATION FOR FIXED INSTALLATION The loudspeaker system is supplied with 4 20 a ceiling plane mounting surface The user must threaded inserts which allow suspension mount supply eyebolts hexnuts washers S hooks ing in either 50 or 30 angles referenced to and cables or chains 3 A k i B E RE a ee eren a ate n ee ae ay i xe i E Pl aS ette sa FF P os 64s en Ce O ne eats ate ates y D ee fy k E 7 6 cm Figure 15 System Dimensions ARCHITECT S AND ENGINEER S SPECIFICATIONS The loudspeaker shall be of the two way multi purpose type consisting of a 16 coaxial type loudspeaker and a dividing network having a crossover frequency of 2 kHz with variable high frequency attenuation The loudspeaker system shall meet the following performance criteria Power rating 150 w average of continuous pink noise band limited from 80 Hz 15 kHz Frequency response smooth and uniformly usable at high levels from 80 Hz 15 kHz Pressure sensitivity 100 dB SPL at one watt 80 Hz 15 kHz measured from one meter on axis Impedance 7 2 ohms minimum The enclosure shall be of the ported bass reflex type constructed of 34 1 9 cm birch plywood damped with sound absorbent glass wool The finish shall be bl
3. ack spatter finish polyurethane paint The dimensions shall be 20V 52 1 cm high by 22 55 8 cm wide by 21 4 54 6 cm deep The loudspeaker shall weigh 58 Ibs 26 4 kg The loudspeaker system shall be the Altec Lansing Model 938 8AD or Model 938 8AE ALTEC LANSING P O BOX 26105 OKLAHOMA CITY OKLAHOMA 73126 0105 U S A 1989 ALTEC LANSING CORPORATION PRINTED IN U S A 5 89 3M 42 07 027608 AL 2565
4. n at 0 1 Rated Power 15 watts See Note 7 i F rj Hh o 1 6 kHz 4 25 kHz Figure 7 One third Octave Polar HORIZONTAL See Note 8 VERTICAL AHGLE idog Bigi Lett 3 0976 3 304 3 510 3 717 3 923 _ J ENERGY dB i 9000 9600 10200 10800 11400 12000 Figure 8 Coverage Angle 8 a _ as ar Zne l Figure 10 Horizontal Off Axis Response Contours DISTANCE m LF Output 9822 Ls 3 3799 meters TIME ws Figure 12 Energy Time Curve See Note 9 NOTES ON MEASUREMENT CONDITIONS 4 2 Figure 1 measurement was taken with network attenuation set in the Flat position Pink noise signal one watt calculated using E2 Zmin 3 16 meter measurement distance referred to one meter On axis one watt calculated using E2 Zmin 3 16 meter Measure ment distance referred to one meter low frequencies corrected for anechoic chamber error This system rating patterned after the AES method for individual drivers where the test signal is pink noise with 6 dB crest factor over the bandwidth of the system with power calculated using Ey Zmin for two hours This measurement made under the same conditions as Pressure Sensitivity but at rated power and takes into account any power compression effects due to non linearities in the system Phase response of the system measured at a time corresponding to the energy arri
5. nt installation When used as a monitor or a small main system the 938 will supply the high level quality sound that is required for churches hotels and other installations SPECIFICATIONS System Type Two way vented full range loudspeaker system Enclosure 100 dB SPL 1W 1M 80 Hz 15 kHz re 20uPa see Note 2 80 Hz 15 kHz see Figure 1 Note 3 150 watts 80 Hz 15 kHz AES method high frequency attentuation Vented type for optimum response built of 44 inch 1 9 cm birch plywood lined with glass wool includes tee nut mounting points on each side and a removable grille 938 8AD red and black five way binding posts and two 14 phone jacks wired in Pressure Sensitivity Frequency Response Power Handling Input Connector Maximum Long Term Output impedance Distribution Pattern Components Crossover Network see Note 4 300 watts 80 Hz 15 kHz continuous program material see Note 12 600 watts peak power 80 Hz 15 kHz see Note 13 122 dB SPL 1M re 20pPa see Note 5 128 dB SPL peak 7 20 minimum maximum inductive phase angle 68 at 8 Hz maximum capacitive phase angle 59 at 20 Hz see Figures 3 and 4 Note 11 60 horizontally by 40 vertically see Figure 8 16 coaxial loudspeaker part number 0 03 026768 938 BAD part number 56 06 027683 938 BAE part number 56 06 027506 Crossover frequency 2 kHz with choice of parallel 938 8AE red and black ti
6. val of the high frequency component as noted on Figure 12 Distortion components invalid above 10 kHz The percentage distortion at any given frequency may be found by graphically 4 1294 DIRECTIVITY INDEX dB Wir ANOLE peg pran 10 T 12 13 31 5 63 125 290 500 1 i K 16K FREQUENCY Hz Figure 9 Q and DI pi te FREGUENET Hri Figure 11 Vertical Off Axis Response Contours 0 5K 10K Sk 20K FREQUENCY Hz Figure 13 Time Energy Frequency Curve See Note 10 taking the difference between the fundamental and harmonic adding 18 dB and applying the formula percentage distortion 100 x 10 dB change 20 The axis of rotation for all polar plots is the apparent apex of the high trequency horn Plots below 200 Hz have not been shown because of their lack of pertinent information The time window has been chosen to resolve the arrival times of low and high frequency components Frequency bandwidth of measurement 800 Hz 2 8 kHz Response decay of the system Time window is the same as used in Figure 12 Energy Time Curve The loudspeaker system should be connected to the eight ohm tap of amplifiers using transformer coupled output sections Continuous program is defined as 3 dB greater than the AES rating using a pink noise signal with 6 dB crest factor Peak power is defined as 6 dB greater than the AES rating using a pink noise signal with 6 dB crest factor ap 713
7. ve way binding posts and XLR connectors wired in parallel Pin 2 is positive and Pin 3 ts negative Replacement H F Model 26420 Diaphragm L F Recone Kit R604 8L Replacement Grille Model RG 938 Dimensions 20 5 52 1 cm high 22 55 8 cm wide 21 5 54 6 cm deep Net Weight 58 Ibs 26 4 kg Shipping Weight 60 Ibs 27 3 kg Finish Black texture finish polyurethane paint black grille cloth m p iw ao 90 W L a amp 180 D o 360 20 50 100 200 500 1K 2K 5K 10K 20K 20 50 100 200 500 1K 2K 5K 10K 20K FREQUENCY Hz FREQUENCY Hz a Figure 1 Frequency Response See Notes 1 and 3 Figure 2 Phase Response See Note 6 f A Moximum inductive Phase Angle is 3 BB af 8 Hz Minimum Impedance amp u is 7 2 ohms at 250 Hz w Z 8 Maximum Capacitive Phase Angle is T p 59 at 20 Hz a Wi E 1 SOUND PRESSURE LEVEL dB FREQUENCY Hz Figure 3 Magnitude of Impedance Distortion Components Raised 18 dB Second Harmonic ll 20 50 100 200 500 1K 2K 5K FREQUENCY Hz 10K 20K Figure 5 Harmonic Distortion at 01 Rated Power 1 5 watts See Note 7 C F3 49 at 80 Hz Copacilive 0 10 20 30 40 50 60 70 RESISTANCE 0 Figure 4 Complex Impedance Distortion Components Raised 18 dB A Second Harmonic SOUND PRESSURE LEVEL dB 20 50 100 200 500 1K 2K FREQUENCY Hz SK 10K Figure 6 Harmonic Distortio
Download Pdf Manuals
Related Search