MASELEC MASTER SERIES MLA-2 Precision 2
Contents
1. s gain reduction circuit is active Green Indicates that the compressor is in circuit on Red The colour changes to red when the input signal causes gain reduction This is particularly useful when the two channels are stereo linked as the VU meters will not show which channel is causing the gain reduction The light will also assist when the unit is located at a greater distance from the user 4 9 Stereo linking This switch enables the intelligent Image Link system that matches the gain reduction applied to both channels The linking is programme dependant Momentary gain reduction due to short duration peaks will not be linked This technique maintains the integrity of the stereo image while avoiding obvious pumping effects resulting from momentary transients on one channel The ImageLink system is independent of all other controls Different ratio attack and release can be set to either channel Issue 1 1 Prism Media Products Limited January 14 1998 Page 19 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 4 10 Threshold range This control is located on the rear panel and is designed to be pre set at the time of installation It selects between two ranges Normal for studio use and High for Mastering use Inthe High setting for a given audio programme the depth of compression will be less The compression threshold is modified dynamical2. Compressor MLA 2 release time Ratio 5 Att 005 Rel 05 OO o SEES TS pepe ape My com eh gree EEE PR NOAA IC IE EEE DE nes 18 2 BF i F ji An Pea AE 29 8 PEA EEE gor ye T D ee E 35 897 E t p EE E E TE Oe TAE 35 85 PSE ape AAA ERE PEP a TT TE a a a 29 8 peje A Pe eee ene aes a ee Lane AAA SCOPE caer ms ae Te a ae TERE a ae SCOPE 341 33 Markers 1 Scope trace 0 00 ms 0 44 dBFS Rel ref point 2 Scope trace 230 04 ms 5 28 dBFS Rel tim secydB The actual time can be measured from the plot by dividing the time interval measured between the markers in the plot above by the gain change between the markers The calculated release time is 0 23s 4 84dB 0 048sec dB Setting was 0 05sec dB 4 6 VU GR This control switches the meter reading between vu Meter displays the output level OVU 4dBu g r Meter displays the average gain reduction dB Issue 1 1 O Prism Media Products Limited January 14 1998 Page 18 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 4 7 Compressor in out This control switches the compressor including input gain and output gain controls in and out of circuit out Compressor by passed Meter displays input amplitude in VU mode In G R mode the meter will stay at OdB in Gain reduction compressor circuit is active 4 8 Compressor indicator lamp This bi colour indicator indicates if the compressor
3. by a similar value and type 20x5mm 250V 315mAT anti surge slow 6 7 Earthing The unit has an internal link connecting the audio ground to the chassis A chassis earth stud is provided on the rear of the unit 6 8 Physical dimensions Weight 9 Ib 4 Kg Width 19 inch 483mm rack mountable Height 2U 90mm Depth 10 25 inches 260mm add clearance for connectors Issue 1 1 Prism Media Products Limited January 14 1998 Page 26 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 7 ELECTROMAGNETIC COMPATIBILITY This equipment is intended for use in an electromagnetically controlled environment To maintain the performance specification it should not be subject to strong magnetic fields such as in the immediate vicinity of a power amplifier or cathode ray tube and all connections should be terminated as described below This equipment does not include digital circuitry or generate high frequencies that could be radiated or conducted from the unit All XLR connections should use a screened twisted pair cable with the screen connected to pin 1 of the XLR connector at both ends 8 REFERENCES 1 AES17 1991 AES Standard Method for Digital Audio Engineering Measurement of Digital Audio Equipment J Audio Eng Soc Vol 39 No 12 pp 961 975 December 1991 FURTHER INFORMATION Enquiries about this product should be addressed to Prism Me
4. noise One of the main problems for compressors is recovery after loud transients often called pumping To avoid this the attack and release times of the MLA 2 are dynamically controlled i e program dependent In short the nominal attack and release times set by the controls are modified according to the program content This is a key feature of the MLA 2 and one which enables the device to operate effectively and transparently on the most difficult signals without introducing the excessive distortion or pumping so noticeable in less sophisticated designs Issue 1 1 Prism Media Products Limited January 14 1998 Page 8 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 3 4 Example MLA 2 in a mastering chain The following are examples of MLA 2 settings for use in a typical mastering chain or in an insertion point in a mixing console Best results will be obtained with a gain structure where OVU corresponds to 4dBu and if the chain includes D A and A D converters with OdBFS digital full scale corresponding to 18dBu LEVEL dBu AMPL dBu 24 000 18 000 12 000 6 0000 6 00 0 0 6 000 12 00 18 00 24 00 a E 2 PEA ES ESAS EME o Jus ls Note Typ attack time 0 02 msec dB typ release time 0 2 sec dB Thres High These transfer curves are shown for a range of settings from gent
5. to provide very high quality signal processing for the most demanding professional applications It has been carefully developed in conjunction with balance engineers producers and mastering engineers to be easy to use to provide a natural and warm sound and to offer a greater degree of transparency in the presence of compression The MLA 2 also offers precision controls which enable exact re creation of previously used configurations 3 3 1 Driving the compressor Early compressors or limiting amplifiers had few controls and were simple to operate Many such devices are still popular today despite or perhaps even as a result of the limitations of their early technology Such devices often employed a drive control which provided progressively more compression depth and input gain when rotated Issue 1 1 Prism Media Products Limited January 14 1998 Page 6 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor Some later devices split this function into two controls which would have to be operated together to achieve the same progressive effect without marked shifts in signal amplitude The MLA 2 uses the drive principle and the control is called Input Gain The compression threshold is left unchanged while the input gain is adjusted to alter compression depth This has the advantage that gain and compression depth are adjusted together and so peak level w
6. where high performance is required The MLA 2 provides a unique set of tools carefully crafted to provide a compressor whose sonic character was the most important design objective The unique character of the device is evident in the technical description of the behaviour of the device The MLA 2 employs state of the art analogue electronics and provides a perfect solution to analogue mastering needs especially used in conjunction with Prism Sound A D and D A converters Also available in the MASELEC MASTER SERIES is the MEA 2 equalizer 2 SUMMARY OF MLA 2 FEATURES Operational Easy to operate with input gain controlling compression depth drive C Minimal gain adjustment needed when changing ratio C Optical gain element for smoothness and freedom from noise C Dynamically controlled attack and release to minimize pumping C Precision stepped controls C ImageLink Intelligent dynamic stereo linking system C Output gain make up C Switchable gain reduction or signal level VU metering Technical C Low noise C Extended headroom with maximum input amplitude of 28dBu C Extended frequency response C Low distortion C Electronically balanced inputs and outputs Issue 1 1 Prism Media Products Limited January 14 1998 Page 4 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 3 GETTING STARTED Itis not necessary to read all the manual before being able
7. 5 CONNECTORS rror erea naaa AS EE E A AS E EA 21 Sul IMPUECOMNECUONS 2 docalacmdasajacudarolsemdasas 2 daa 21 5 2 Output connections evisos 22 5 3 Rear panel connectors usada aia 23 6 SPECIFICATION 2 ds 23 6 1 Analogue INpuiS sust a dl id 23 6 2 SAMalogue QUIDLAS ac ce ea aa oats ot Sete or ae ose 24 6 3 Performance specification 0000 0c eee eee eee 25 6 4 Servicing and repair venue ede cew cue sen ee Jew ewe 25 6 5 Mains transformer voltage selection 00002 eee ee 26 Issue 1 1 Prism Media Products Limited January 14 1998 Page 2 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor A ata wiancaate ate mone 26 6 7 Edi ta o eee ee ae e 26 6 8 Physical dimensions ys ri e WP a ie Wes 26 7 ELECTROMAGNETIC COMPATIBILITY Lo 27 8 REFERENCES cerrarla eet ect 27 Manual Revision History Issue 1 1 January 14 1998 Issue 1 0A 29 October 1997 Issue 1 0 27 October 1997 Product Revision History October 1997 This manual is for use with units having serial numbers beginning with 1 thus MLA2 1 xx xxxx Issue 1 1 Prism Media Products Limited January 14 1998 Page 3 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 1 INTRODUCTION The MLA 2 Precision 2 Channel Compressor is intended for professional audio use in recording mixing and mastering applications
8. CATION 6 1 Analogue inputs The analogue inputs are on a three pin XLR connector with positive and negative signal polarities on pins 2 and 3 respectively and screen on pin 1 Pins 2 amp 3 have a high impedance path to the chassis earth Differential input impedance 27 kS pin 2 to pin 3 Single ended input impedance 27 kS pin 1 to 2 or 3 Coupling impedance to chassis 1 0 MS chassis pin 1 to 2 or 3 Common mode range 10 Vrms note I P is not floating Note Some earlier units are 38 4 kS or 28 2 kS Issue 1 1 Prism Media Products Limited January 14 1998 Page 23 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 6 2 Analogue outputs The analogue outputs are on a three pin XLR connector with positive and negative signal polarities on pins 2 and 3 respectively and the mid point on pin 1 Differential output impedance 62S pin 2 to pin 3 balanced Single ended output impedance 31S pin 1 to 2 or 3 unbalanced Issue 1 1 O Prism Media Products Limited January 14 1998 Page 24 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 6 3 Performance specification Specifications quoted in this section are to AES17 1991 ANSI S4 51 1991 Ref 1 with input level set to 22dBu except where stated For Compressor in measurements the in out switches are illuminated and other settings are
9. Input Gain 10dB Output Gain 10dB Threshold High Ratio 2 1 Attack 0 100ms dB Release 0 10sec dB Maximum input amplitude 28dBu Output noise Compressor out lt 100dBu Compressor in lt 90dBu Frequency response 0 1 0 4dB lt 1Hz to gt 50 kHz 30B points 0 03Hz to gt 350kHz Crosstalk less than 100 dB 20 Hz to 20 kHz Un driven input terminated 150R Dynamic range Measured at 32dBu Compressor out gt 125dB Compressor in gt 107dB 6 4 Servicing and repair There are no user serviceable parts inside this unit Repairs should only be undertaken by qualified electronics technicians or engineers Issue 1 1 O Prism Media Products Limited January 14 1998 Page 25 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 6 5 Mains transformer voltage selection The mains transformer has a tapped primary to allow operation at nominal voltages of 115V or 230V A rear panel slide switch selects the mains voltage range as 120V 240V Ensure that the correct voltage range is selected before using the MLA 2 6 5 1 Mains voltage range 90 130V nominally 120V or 180 260V nominally 240V operation The selected supply voltage range is indicated on the rear panel slide switch 6 5 2 Power Consumption 15W max 6 6 Fuse There is one mains fuse accessible externally in the IEC320 mains inlet If this fuse is blown it should be replaced
10. MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor Operation Manual Issue 1 1 January 14 1998 7 7 Y ie Y eS Y Ly Consultant engineers in DSP real time control sohtware Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor CONTENTS 1 INTRODUCTION ona A AAA AAA 4 2 SUMMARY OF MLA 2 FEATURES 00 000 eee eee 4 3 GETTING SIARTED 2 30 toe Sek ee oe tee O eee ee ot Se 5 3 1 Unpacking your MLA 2 ropas Segre oa e o oe 5 3 2 Using the MLA 2 for the first time ooooocoooooo 5 3 3 MLA 2 product concept and capabilities 6 3 4 Example MLA 2 in a mastering chain ocooooccccoco oo 9 3 5 Example MLA 2 on a mixer stereo output 10 4 OPERATION pass ashok e Pic gute ace ate Cia ete aun ae Mie Ge ane ate Dl ed 12 Ale EN 12 42 OUMDUCGAN e 22 04 3200 tte ee ee et bee eee eee ates ab 13 43s TRANG ii A A AA ig og Tanga Se ag RS 14 44 gt Attack UME usos dn foe b s OE is Os Oy Re e RE OER EOE Seb 16 452 REISS TNC siririn Boogie a R Bro EON RAE Bee GORO Bre hee 17 4 6 NUIGR ts cvetewe set asn chat eine ee hee hase se ees 18 4 7 Compressor in out 5 jee wees ered we oes eae Soe Ses Se Sie ewe Te Sie eS 19 4 8 Compressor indicator lamp 000 cee eee eee eee 19 4 9 ST sasda di ane eae A A cag 19 4 10 Thresholdrange mirs oi a se ase pig ave le ase dg ve esse wie te eee 20
11. alanced sources Balanced Output Unbalanced Output ground Using the above method when driving the MLA 2 with unbalanced sources should provide best results Issue 1 1 O Prism Media Products Limited January 14 1998 Page 21 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor Note The maximum input amplitude is reduced by approximately 6dB from the nominal 28dBu when driving the MLA 2 from an unbalanced source 5 2 Output connections This diagram illustrates correct connection for balanced and unbalanced loads out Balanced Input out p ground out Unbalanced Input out ground Using the above method for driving unbalanced loads should provide best results It employs Ground Loop Compensation and the signal level remains unchanged compared to balanced operation Note When driving unbalanced loads with the MLA 2 the maximum output level is reduced by approximately 6dB from the nominal 28dBu Issue 1 1 Prism Media Products Limited January 14 1998 Page 22 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 5 3 Rear panel connectors A Audio I O C Left Channel Input C Left Channel Output C Right Channel Input C Right Channel Output B Earthing Stud Link to a good quality ground connection by the most direct route C IEC Mains Inlet Switched 6 SPECIFI
12. annel Compressor Note Typ attack time 0 02 msec dB typ release time 0 2 sec dB Thres High The transfer curves are shown for a range of settings from gentle to severe compression Use these as a starting point if you are unsure of suitable settings With the suggested gain structure the compressor will generally prevent clipping subject to the attack time setting If clipping occurs and if it is objectionable or must be avoided for other reasons try reducing the attack time If this does not solve the problem next try reducing the input gain This will result in the finest possible gain trim as the output gain change that results is reduced subject to the ratio setting Comparing these settings with those of section 9 it can be seen that in general more gain is used in the former case of the digital mastering chain In the latter case the MLA 2 input driven by a console stereo output might reach 24dBu or more In each case the MLA 2 input level is represented on the horizontal axis with the compressed MLA 2 output level on the vertical axis For exceptionally hot levels and when using A D converters set with the gain structure recommended above such as Prism Sound AD 124 or AD 2 use the Prism Sound Overkiller passive soft clipper in series with the MLA 2 output Issue 1 1 O Prism Media Products Limited January 14 1998 Page 11 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precis
13. dia Products Limited William James House Cowley Road Cambridge CB4 4WX UK Phone 44 0 1223 424988 Fax 44 0 1223 425023 Email tech support prismsound com Issue 1 1 Prism Media Products Limited January 14 1998 Page 27 of 27
14. e audio signal amplitude and dynamics Increasing the input gain can not cause overload Issue 1 1 O Prism Media Products Limited January 14 1998 Page 12 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor The following plot illustrates the operation of the input gain control Threshold range is High in this example LEVEL dBu AMPL dBu 24 000 18 000 12 000 6 0000 0 0 6 00 0 0 6 000 12 00 18 00 24 00 NOTE Refer to section 3 3 for an overview of MLA 2 operation and see section 4 10 regarding threshold 4 2 Output gain This control increases the output audio amplitude afterthe gain reduction circuit over the range OdB to 20dB in 1dB steps The Output gain control does not affect the amount of gain reduction compression NOTE Refer to section 3 3 for a brief overview of MLA 2 operation Issue 1 1 O Prism Media Products Limited January 14 1998 Page 13 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 4 3 Ratio This control adjusts the severity of the compression applied to loud signals i e those which exceed the compression threshold The MLA 2 automatically adjusts the threshold to maintain output level for small amounts of gain reduction lt 6dB GR This is best understood by looking at the transfer curves pl
15. ill only vary by a small amount determined by the ratio which sets the severity of compression Therefore to increase the depth of compression or to bring the quieter parts of the mix or instrument dynamics forward simply rotate the input gain control clockwise until the desired effect is obtained Another problem with less sophisticated designs is that as the ratio is increased the output level drops dramatically The MLA 2 reduces this effect particularly for moderate amounts of gain reduction by making small adjustments to the threshold depending on the ratio setting This results in less variation on output level for a given input range as the ratio is varied For larger amounts of gain reduction much more than about 4 6dB as ratio is increased it will be necessary to compensate by increasing the output gain In general for mastering applications use the High threshold setting switch on the rear of the MLA 2 and for recording applications such as for an instrument in an insert point use the Low threshold setting Issue 1 1 Prism Media Products Limited January 14 1998 Page 7 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 3 3 2 Dynamic behaviour The gain element of the MLA 2 is an optical device and not the more conventional VCA This provides a smooth transition between linear and compressed operation with a low level of
16. indicate the average attack time NOTE Refer to section 3 3 for a brief overview of MLA 2 operation Nominal attack times ms dB are 0 005 0 020 0 100 0 500 1 0 1 5 MLA 2 attack Rat 2 1 I P gain O P Gain OdB Rel 0 02 Att 1 0 2 5 SCOPE 0 0 i i H f 10 81 ms 16 15 21 48 26 81 32 15 37 48 42 81 48 15 SCOPE 53 48 Markers 1 Scope trace 21 48 ms 0 28 dBFS Measuremen t start 2 Scope trace 23 48 ms 2 21 dBFS 1 0ms dB linear attack This graph indicates the attack characteristic MLA 2 settings were Input Gain 0dB Output Gain 0dB Threshold Low Ratio 2 1 Attack time 1 0msec dB Release time 0 02sec dB The attack time setting can be calculated from the plot by calculating the ratio of ms dB of the time interval and gain change between markers 1 amp 2 namely Attack time 2ms 1 93dB 1 04msec dB Setting was 1 0msec dB Issue 1 1 O Prism Media Products Limited January 14 1998 Page 16 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 4 5 Release time Setting of this control will determine the release time For real audio programme with complex waveforms the setting indicates the maximum release time caused Short duration peaks will not cause long release times NOTE Refer to section 3 3 for a brief overview of MLA 2 operation Nominal
17. ion 2 Channel Compressor 4 OPERATION The unit is designed for either stereo or 2 channel operation and each channel is controlled independently by an identical set of controls A linking facility is provided that enables tracking of the two channels for stereo operation When selected stereo linking is intelligently controlled by the ImageLink system described below Each channel has controls for Compressor in out Input gain Output gain Ratio Attack Release ANIANIANNA Some of these parameters are dynamically controlled More detailed descriptions are provided below Metering is provided for each channel and meter function may be signal amplitude VU dynamic characteristic or gain reduction GR according to the meter function switch The meter scale is in dB units There is a global threshold selection provided by a locking toggle switch on the rear of the unit This is designed to be set at installation and should not require changing afterwards See section 20 for details of the threshold range switch 4 1 Input gain This control attenuates the input audio signal before the gain reduction compressor circuit over the range 0dB to 20dB in 1dB steps Increasing the input gain or reducing attenuation will drive the compressor harder The depth of compression will be increased Output level will also increase subject to other settings including the compression ratio and attack and release times and th
18. le to severe compression Use these as a starting point if you are unsure of suitable settings With the suggested gain structure the compressor will generally prevent clipping subject to the Issue 1 1 O Prism Media Products Limited January 14 1998 Page 9 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor attack time setting If clipping occurs and if it is objectionable or must be avoided for other reasons try reducing the attack time If this does not solve the problem next try reducing the input gain This will result in the finest possible gain trim as the output gain change that results is reduced subject to the ratio setting 3 5 Example MLA 2 on a mixer stereo output This section provides some sample settings that might be selected when using the MLA 2 to control the output of a mixer when driving into a digital recorder or A D converter Best results will be obtained with a gain structure where OVU corresponds to 4dBu and OdBFS digital full scale on the A D output corresponds to 18dBu LEVEL dBu AMPL dBu 24 000 18 000 12 000 6 0000 6 00 0 0 6 000 12 00 18 00 24 00 TAN 9 E E i ee Greatest Compression o 1 Je Issue 1 1 O Prism Media Products Limited January 14 1998 Page 10 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Ch
19. ly within these ranges by the MLA 2 control circuitry according to programme content Normal Threshold Threshold range 10 5 dBu to 14 5dBu High Threshold Threshold range 1 5dBu to 23 5dBu Application Note Adjustment of threshold might be desired in order to adjust compression depth However the MLA 2 provides a more convenient adjustment in the form of Input Gain which has the benefit of increasing compression depth with a clock wise rotation In addition the audio level does not fall as depth is increased Issue 1 1 O Prism Media Products Limited January 14 1998 Page 20 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 5 CONNECTORS For this equipment the convention for balanced XLR connections pin 2 is hot or and pin 3 cold or Some users and equipment implement the opposite This should not be problematic providing a consistent implementation is used throughout Note When interfacing to other devices such as A D and D A converters it may be necessary to check the manufacturers polarity convention if the correct absolute phase is to be maintained However this does not affect use of the MLA 2 with either polarity convention Balanced analogue audio connections should use a good quality screened twisted pair lead Unbalanced connections must also be screened 5 1 Input connections This diagram illustrates correct connection for balanced and unb
20. otted for a range of ratio settings For completeness plots are provided for both High and Low threshold settings NOTE Refer to section 3 3 for a brief overview of MLA 2 operation Ratios available 1 4 1 1 7 1 2 1 3 1 5 1 8 1 oe LEVEL dBu AMPL dBu 24 000 18 000 12 000 6 0000 6 000 6 00 0 0 6 000 12 00 18 00 24 00 Range of ratios at high threshold setting The rotation point of the compressor characteristic curves at about 16dBu is the key to maintaining nearly constant output amplitude and the threshold variation is also clearly visible Issue 1 1 Prism Media Products Limited January 14 1998 Page 14 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor en LEVEL dBu AMPL dBu 9 0000 6 0000 3 0000 3 000 6 000 6 00 3 00 0 0 3 000 6 000 9 000 12 00 Range of ratios at low threshold setting Note that the threshold range and the rotation point are now 9dB lower than in the high threshold case Issue 1 1 Prism Media Products Limited January 14 1998 Page 15 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor 4 4 Attack time Setting of this control will determine the attack time For real audio programme with complex waveforms the setting will
21. release rates sec dB are 0 02 0 05 0 10 0 20 0 40 1 0 The following illustrations were captured using a Prism Sound Dscope test system and AD 124 amp DA 1 A D and D A converters The test method was to select the ImageLink feature to link the gain reduction on both channels and to drive the measured channel with a low below threshold sinewave while driving a higher level into the other controlling channel The controlling channel input was muted and the Dscope set to trigger on an increase in level on the measured channel The release time measured is that set on the controlling channel Settings for this test were as follows Threshold range High Controlling Channel Input Gain OdB Output Gain OdB Ratio 5 1 Attack Time 0 005 ms dB Release time 0 05 sec dB Measured Channel Input Gain 20dB This forces level below threshold Output Gain OdB Ratio 5 1 Attack Time 005 ms dB Release time 0 05 sec dB The test signal was applied at 17dBu on both channels prior to trigger and then the controlling channel was muted Issue 1 1 O Prism Media Products Limited January 14 1998 Page 17 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel
22. switch should illuminate when switched on If it fails to light the power may be absent or the unit may be faulty Check the mains supply and try again If the problem is still evident contact your distributor Issue 1 1 Prism Media Products Limited January 14 1998 Page 5 of 27 Prism Media Products Limited Operation Manual MASELEC MASTER SERIES MLA 2 Precision 2 Channel Compressor Set the rear panel Threshold switch to Low for recording or High for mastering or for working on a stereo mix Pull the switch lever to overcome the safety lock Switch the secondary power switch on the front of the MEA 2 to ON Set the meter function switch to G R Gain Reduction Set the Compressor In Out switch to In Either by momentarily muting or disconnecting the inputs check that the meter indication is at or very near to OdB Note When the unit is first switched on this indication may be fractionally below the 0dB reading This is normal After a few minutes during which time the unit will stabilise at its normal operating temperature this will settle at OdB Re connect or unmute the inputs Switch the monitor selection to monitor the MLA 2 output A suggested starting point for control settings is Ratio 2 Attack 0 100 Release 0 10 Input Gain 10dB Output Gain 10dB ANANDA The unit is now ready to use 3 3 MLA 2 product concept and capabilities The MLA 2 Precision 2 Channel Compressor is designed
23. to use the MLA 2 Precision 2 Channel Compressor This section contains all the information required for you to get going straight away 3 1 Unpacking your MLA 2 Check that you have the following items and that they are undamaged a MLA 2 Precision 2 Channel Compressor unit MLA 2 Precision 2 Channel Compressor operation manual this book 1EC320 type mains lead with appropriate plug for your supply Check that the slide switch mounted on the rear panel is set to the correct mains voltage range 120 setting 9V 130Vac 50 60Hz 240 setting 180 260Vac 50 60Hz and that the plug fitted to the mains lead is of the correct type If not DO NOT CONNECT THE MAINS SUPPLY but contact your distributor Please keep the packaging for re use in the event that the unit should be shipped to another location or in the event that it should ever need to be returned to the manufacturer for repair or upgrade 3 2 Using the MLA 2 for the first time Refer to section 21 for wiring details of connecting leads Connect a source of balanced audio to the input connectors on the MLA 2 Connect the output of the MLA 2 to a monitoring system or to a tape recorder input Connect the mains supply to the MLA 2 unit There is a main power switch on the rear of the unit and an auxiliary switch on the front which is more convenient to use if the equipment is rack mounted and the rear panel is inaccessible The indicator lamp integral in the rear mounted mains
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