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The 75Hz high pass filter is useful for removing subsonics such as wind
and stage noise and will help produce a much tighter bass and vocal
sound.

M A K I N G   A   C O M P R E S S O R   F R E Q U E N C Y   C O N S C I O U S
Inserting an equaliser such as the Millenium EQX20 (or even the EQ from
the MPX10) into the side chain of the compressor will make it more
sensitive to certain frequencies. Examples of this technique are De-Essing
and De-Popping.

S P E C I A L   E F F E C T S
A passable telephone voice can be created by cutting frequencies below
300Hz and above 3kHz. Use the LMF and HMF sections, lowest Q (CW)
setting and adjust their respective FREQUENCY controls accordingly.

E N H A N C I N G   T H E   F A C I L I T I E S   O N   Y O U R   M I X I N G
C O N S O L E
Patch any or all of the sections of the MPX10 into a channel or Group insert
on your console to add Expander, Compressor and EQ processing to your
signal path.

5 . 5

O U T P U T

The Output section of the MPX10 provides output level adjust and signal
level metering. In general the OUTPUT control will be kept at '0' (12
o'clock) whilst setting-up and then only adjusted if the following equipment
is being under or over driven.

Remember when using OUTPUT to reduce signal levels there is a danger
of the MPX10 clipping internally.

The '0' led on the OUTPUT LEVEL meter lights when +4dBu (at the XLR)
or -10dBV (at the TRS jack) is present at the output connectors.

Summary of Contents for MPX10

Page 1: ...MULTI PROCESSOR OPERATION MANUAL ...

Page 2: ...Page 2 Version V1 April 2000 ...

Page 3: ...6 External connections 6 3 Warranty 9 4 Description of controls 10 15 4 1 Input section 10 4 2 Noise Reduction and Compressor section 11 4 3 Equaliser section 13 4 4 Output section 5 Applications 16 21 5 1 Input 16 5 2 Compressor 16 5 3 Expander 18 5 4 Equaliser 18 5 5 Output 20 6 Circuit description 21 6 1 Inputs 22 6 2 Expander and Compressor 22 6 3 Output 23 7 Specifications 24 ...

Page 4: ...d Microphone inputs with 48V phantom power High impedance 0 5M DI input High and low pass filtering Downward expander Noise Reduction Auto Compressor with variable Threshold Ratio and Gain In built De ess function HF and LF shelving EQ 2 parametric mid range sections with Gain Frequency and Q controls Output level adjust Gain Reduction and Output metering Ground compensated outputs at 4dBu and 10d...

Page 5: ...Page 5 ...

Page 6: ...E DIRECTIVE LVD The MPX10 has been designed to meet the latest Electromagnetic Compatibility EMC regulations However we recommend you do not operate the unit close to strong emitters of electromagnetic radiation such as power transformers motors mobile telephones or radio transmitters The unit should only be connected to a power supply of the type described in 2 4 POWER REQUIREMENTS or as marked o...

Page 7: ...available for Japan and a 220V version for Republic of Korea The mains lead connections to the appliance are coloured in accordance with the following code Green and Yellow Earth Blue Neutral Brown Live WARNING THIS APPLIANCE MUST BE EARTHED 2 5 SIGNAL LEVELS For input level ranges see GAIN control in the Description of Controls section The MPX10 outputs both 10dBV and 4dBu operating levels withou...

Page 8: ...d distortion Pin 1 Screen Pin 2 Hot Pin 3 Cold PUSH Microphone Input XLR connections view of connector on MLX2 LINE TRS Tip Hot signal Ring Cold signal SleeveScreen signal ground Sleeve Screen Ring Cold Tip Hot Fig 2 6 3 Line Input and 10dBV Output connections The 20k input impedance of the LINE input is suitable for most types of equipment For un balanced operation join Ring and Sleeve on your co...

Page 9: ...ctly to electric guitars OUTPUT jack Tip Hot signal SleeveScreen signal ground This connector provides an unbalanced line level output from the Mic Line DI preamplifier Plugging a jack into this connector does not effect the signal path through the MPX10 Source impedance is 100 which is suitable for driving loads of 1k and greater ...

Page 10: ...side chain circuitry This path must be completed by the external connected equipment The side chain in out signal path affects both the Compressor and the Expander response Commonly used to insert an equaliser into the sidechain to produce frequency conscious compression such as de essing Because each section of the MPX10 has Input and Output break jacks it is possible to plug the EQ of the MPX10 ...

Page 11: ...Page 11 OUTPUT jack Tip Hot signal SleeveScreen signal ground An unbalanced output from the Compressor section ...

Page 12: ...om the EQ section OUTPUT SECTION INPUT jack Tip Hot signal SleeveScreen signal ground Unbalanced input to the Output section Half Normalled to the output of the EQ section 4dBu XLR Pin 1 Screen Signal ground Pin 2 Hot ve Pin 3 Cold ve For un balanced operation join Pins 1 and 3 on your connecting cable 10dBV TRS Tip Hot signal Ring Cold signal SleeveScreen signal ground For un balanced operation j...

Page 13: ... necessary to return the unit to an LA Audio authorised service centre or to the factory with a dated receipt as proof of purchase After repair the unit will be returned to you free of charge Limitations This warranty does not cover damage resulting from accident or misuse The warranty is void unless repairs are carried out by an authorised service centre The warranty is void if the unit has been ...

Page 14: ...ontrol gives a unity gain setting for the Line input CLIP led Lights 3dB before maximum signal level to show transient peaks approaching clipping Signals which cause the CLIP led to light briefly do not generally produce audible distortion However if the CLIP led lights continuously reduce the GAIN control ccw until CLIP led only lights occasionally LINE switch This switch selects between Micropho...

Page 15: ...nnecting cables although there are certain acoustic problems and specialised miking techniques which use phase reversal FILTER switch This switch inserts a 75Hz 3dB frequency 12dB octave high pass filter into the signal path after the input amplifier Useful for removing low frequency sounds such as rumble and stage noise Can also be used in conjunction with the EQ section to fatten bass sounds wit...

Page 16: ...has fallen below Threshold Please note unlike a gate led which shows that the gate is fully open or closed the EXP led lights to show the signal has fallen below the set Threshold The actual amount of signal attenuation is displayed on the GR Gain Reduction meter COMPRESSOR THRESHOLD control This control sets the signal level above which compression starts The Threshold range is 30dBu CCW to 20dBu...

Page 17: ...e in gain is abrupt The MPX10 has a Soft knee control system which provides a gradual change between compression levels ATTACK RELEASE switch The MPX10 compressor has 4 program dependant Auto Attack and Release settings SLOW mode switches out Attack 20mS to 100mS Release 2S FAST mode switches in Attack 5mS to 70mS Release 0 5S In SLOW mode the compressor reacts to the average level of the input si...

Page 18: ...f the signal path so that comparisons can be made between compressed and un compressed signals GAIN control Because compression is a gain reduction process the output of the compressor is often at a lower level than the normal operating level Some way of restoring the signal to its pre compressed level is required The Gain control provides adjustment to restore output level after compression 4 3 E...

Page 19: ...ects a very small band The Q control on the MPX10 has a range of 0 3 3 octaves to 12 1 12th octave see the following diagram In general lower Qs are used when boosting and higher Qs when cutting see applications FREQUENCY control This control adjusts the centre frequency for LMF Low Mid Frequency cut or boost The LMF FREQUENCY control has a 40 1 range and is adjustable from 60Hz CCW to 2k4Hz 2 4kH...

Page 20: ...or the HMF section HF control High frequency shelving equaliser Provides 15dB cut or boost at 12kHz 12kHz switch Inserts a 12kHz 6dB octave filter into the post EQ signal path The filter is switched separately from the 4 band EQ and is available when the EQ is bypassed BYPASS switch Switches the 4 band equaliser in and out of circuit allowing A B comparisons on EQ settings Please note that the EQ ...

Page 21: ...the applied gain reduction GR in dBs In BYPASS the display is dimmed but still displays the amount of gain reduction which would be applied if the compressor were to be switched in OUTPUT LEVEL meter The led meter displays the overall output level of the MPX10 The 0dB led corresponds to 4dBu or 10dBV at the associated output connector POWER indicator The green POWER indicator is lit whenever power...

Page 22: ...of the unit is a high impedance 0 5M input for electric guitars basses and other instruments with passive pickups The high input impedance uses an FET device to ensure that the instruments pickups are not loaded thus preserving the instruments tonal quality and signal level The DI gain range is designed to cope with the high output of active basses If your mixing console doesn t have a instrument ...

Page 23: ... to reduce signal levels just before the recorder reaches clipping Start with AUTO set to fast mode Signal levelling Signal level variations can occur when the distance between the vocalist and microphone changes The MPX10 compressor can be used to level out the result of poor microphone technique producing an even sound Set RATIO to around 4 1 and adjust THRESHOLD for a gain reduction of 6 to 10 ...

Page 24: ...ssively attenuating the signal level when the it drops below a defined level The progressive action low ratio and relatively long release time makes the audible operation of the expander far less obstrusive than a noise gate Basic set up reducing background noise Start with the THRESHOLD set CCW to its most sensitive 70dB which effectively keeps the expander off EXP led OFF no attenuation Listen t...

Page 25: ...the final solution involves cutting rather than boosting as boosting produces a more apparent effect of highlighting the hum noise boom or whatever Gain and Q should then be adjusted to give the best subjective result In general low Qs wide bandwidth are useful for boosting without producing too much peaking or phasing effects High and Low shelving type equalisation can be simulated by setting the...

Page 26: ... 250Hz Toms Slap at 3 5 5kHz Boomy around 300 350Hz Bass 600 250Hz Bass guitar Slap at 1kHz String noise at 1kHz Bite at 2 5kHz Boomy at 125 220Hz Bass 40 100Hz Acoustic guitar Sparkle above 4kHz Boomy at 200 250Hz Body at 125Hz Tinny at 2 3 5kHz Electric guitar Sex 600 900Hz Boomy below 80Hz Bass 125 250Hz In the way 1 3kHz Bite 2 5kHz Sparkle at 3 5kHz Piano Bass below 125Hz Tinny around 1 2kHz ...

Page 27: ...st Q CW setting and adjust their respective FREQUENCY controls accordingly ENHANCING THE FACILITIES ON YOUR MIXING CONSOLE Patch any or all of the sections of the MPX10 into a channel or Group insert on your console to add Expander Compressor and EQ processing to your signal path 5 5 OUTPUT The Output section of the MPX10 provides output level adjust and signal level metering In general the OUTPUT...

Page 28: ...sor Sidechain Threshold EXP Expander Sidechain 48V Line DI Phase Line Mic Mic Line DI Clip Gain Output DS Filter Input Output RMS Detector Input HF HF Gain Freq Q 2 x Mids LF LF Filter Output Bypass Filter Output 10dBV 4dBu Input Output Level Fig 6 0 1 Block diagram of the LA MPX10 showing the main signal paths ...

Page 29: ...Filter is a 2nd order 12dB Oct highpass optimised for maximally flat response above the cutoff frequency The 3dB frequency is 75Hz 6 1 EXPANDER COMPRESSOR Gain reduction for the Expander and Compressor is provide by a single VCA voltage controlled amplifier which responds to the combined control voltage produced by the Expander and Compressor sidechains This parallel control topology prevents inte...

Page 30: ...mpared to the RMS voltage and when this exceeds the reference the difference is forwarded to the Ratio control RATIO The difference voltage from the Threshold stage is amplified or attenuated depending on the setting of Ratio This control voltage defines the amount of compression once Threshold has been exceeded ...

Page 31: ...and the Gain Reduction meter LINK The LINK connector allows the RMS detectors of two MPX10s to be joined together for stereo operation GAIN The GAIN control adds a DC offset voltage to the combined Expander Compressor sidechain control voltage 6 3 OUTPUT The Output level control provides 20dB gain adjustment The level meter displays the ouput of this stage The final output stage is a balanced impe...

Page 32: ...DI 0dB to 30dB Clip led Lights 3dB before clipping 18dB typical Phantom Power 48V Input select Mic Line or DI Phase 0 or 180 Highpass filter 12dB Oct below 25Hz to 250Hz NR Threshold 70dB to 0dB NR ratio 2 1 NR Attack Release Attack 1mS Release 0 5S Comp Threshold 30dB to 20dB Ratio 1 1 to 20 1 Attack 5mS fast 20mS slow Release 0 5S fast 2S slow Equaliser LF 15dB 80Hz LMF 15dB 60Hz to 2 4kHz HMF 1...

Page 33: ...Page 33 Weight Unit 2 2kg Shipping 2 85kg LA Audio reserves the right to alter any feature or specification without prior notice E OE ...

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