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Basic Setup & Applications 

 

3.2 Basic Applications 

 

Example setup compressing a voice or vocal track. 

Probably the most common use of a compressor is to limit the dynamic range 
of a vocalist during a live performance or a recording. It is almost always 
necessary to compress a vocal take during a recording session. Most 
vocalists have a very wide dynamic range, and if the vocalist does not have 
'studio' experience, the dynamic range of the vocal performance can be 
enhanced by the microphone techniques demonstrated during a session. 
 
This wide variation in level makes it difficult to properly record a vocal take, 
especially in digital multi-track recorders which have definite limitations in 
headroom. 
 
Compressing a vocal also makes it easier to place the vocal track in a mix so 
that it remains 'in your face' throughout the track. 
 
To set up for a vocal take, insert a channel of your ACP-22 into the same 
channel as the microphone on your mixer. If your mixer has an 

insert

 point, 

insert the compressor there. If you don't have an insert point you will have to 
place the compressor after your mixer's bus-output or whichever output 
you're using by coming out of your mixer to the input of the ACP-22; then 
out of the ACP-22 to the input of your recorder. If you're using a stand alone 
mic preamp; patch the ACP-22 

after

 the preamp and then to the recorder. 

 
Turn the 

threshold

 of the channel's compressor you're using completely 

counter-clockwise. If you've gotten the cables right, you should see the 
LED's above the 

threshold

 knob of the channel you're using flashing when 

you talk into the microphone. Make sure that the channel on the ACP22 has 
the following setup: 

Link button is out, Bypass is out, Auto is in, Soft is 

out, Gate Threshold knob is fully counter-clock wise, Compressor Ratio 
knob is set to 1:1 (fully counter clockwise).

 

 
To set the compressor: turn the 

ratio

 to the 

2:1

 mark on the legend. With the 

vocalist yodeling into the mic, turn the compressor's 

threshold

 until the gain 

reduction meters read about -7dB. Now you will probably need to boost the 
compressors' output by turning the

 Gain

 knob clockwise so that 

 
 

Summary of Contents for ACP-22

Page 1: ...ACP 22 Two Channel Stereo Compressor Limiter Gate User s Manual VERSION 1 1 ...

Page 2: ...ease refer to your local distributor Limited Warranty Outside of the U S PreSonus Audio Electronics products are warranted only in the country where purchased through the authorized PreSonus distributor in that country against defects in material and workmanship The specific period of this limited warranty shall be that which is described to the original retail purchaser by the authorized PreSonus...

Page 3: ... Connections 2 1 Front Panel Basic Layout 2 2 Compressor Controls 2 3 Gate Controls 2 4 Gain 2 5 Bypass Link 2 6 Patch Panel 2 7 Power 3 Basic Setup Applications 3 1 Some Basic Patching 3 2 Basic Applications 4 Technical 4 1 Specifications A Appendix A word about compression ...

Page 4: ...TOC Intentionally Blank ...

Page 5: ...ressors Limiters Both channels of your ACP 22 contains an audio compressor that can also be setup as a limiter by varying the ratio of compression You have broad control over threshold ratio attack and release for each processor You can select between auto or manual attack and release curves and hard or soft knee compression types refer to the application section of this manual for a quick tutoria...

Page 6: ...king tracks behind a narrator for auto mixing a service broadcast or performance When both channels are linked together the send of the sidechain jack of the master channel contains a mix of both the channels in the link a cool feature that allows for control over both channels of processing with one sidechain send return See the section on sidechaining for application notes Separate Gate Keying J...

Page 7: ...Overview To Get Help Call Us 1 800 750 0323 9AM to 5PM CST Visit our World Wide Web site http www presonus com Email Us presonus presonus com ...

Page 8: ...sor Limiter Noise Gate Gain output control Link Bypass Control 2 2 Compressor Controls Threshold The Compressor threshold sets the level at which the onset of compression begins When the signal is above the threshold setting it becomes eligible for compression Turning the threshold knob counter clockwise causes more of the input signal to become compressed if you have a ratio setting of greater th...

Page 9: ...r acts on the input signal A slow attack time fully clockwise allows the beginning envelope of a signal commonly referred to as the initial transient to pass through the compressor uncompressed whereas a fast attack time fully counter clockwise subjects the signal to the ratio and threshold settings of the compressor instantaneously The Attack control is only active when the Auto button is not pus...

Page 10: ...s the level set by the threshold With soft knee compression the onset of gain reduction occurs gradually after the signal has exceeded the threshold producing a more musical response to some folks Auto When pushed in the auto button places the compressor in automatic attack and release mode The attack and release knobs become inoperative and a pre programmed attack and release curve is used 2 3 Ga...

Page 11: ...e must be taken especially with regards to percussive instruments to avoid gate chatter Longer release times usually eliminate chattering and should be set by listening carefully for the most natural release of the signal to which the gate is being applied Range The gate range button sets the amount of gain reduction occurring when the gate closes Therefore if the range button is pushed in led on ...

Page 12: ...all processing being performed by your ACP 22 and returns the signal to unity gain You should use bypass often when setting up your ACP 22 to compare the before and after results of the signal processing effecting your audio signal Bypass affects both the gate and the compressor When in Bypass the Link function is interrupted and defeats the stereo link Link When the Link button is pushed in chann...

Page 13: ...ectors or balanced XLR connectors The input can handle up to 24dBu unbalanced or up to 18dBu balanced signal levels Output The output jacks accept balanced XLR or unbalanced tip sleeve connectors The output will deliver up to 24dBu in signal level balanced or unbalanced Cable Connection Diagrams ...

Page 14: ...Gating Sidechain The sidechain jack on each channel interrupts the signal that the compressor and or gate is using to detect the audio signal for processing When no connector is inserted into this jack the input signal goes directly to the compressors control circuitry normaled When a connector is inserted into this jack the signal path is broken If you have inserted a tip ring sleeve connector th...

Page 15: ...m built in power supply no wall wart We can t stand them either This way you can be assured of clean power combined with rugged construction that has been designed to last Power Selection Before powering on your ACP 22 for the first time be sure to check the position of the power selector Make certain that the power voltage level selected matches that of your country s outlet Power Switch I ON 0 O...

Page 16: ...Controls Connections Notes ...

Page 17: ...Basic Setup Applications 3 1 Some Basic Patching Inserting into your mixers insert points unbalanced After your mixers main outputs balanced ...

Page 18: ...Basic Setup Applications Between multi track recorder inputs outputs to mixer outputs inputs unbalanced Sidechain insertion of an equalizer for de essinq specific frequency gating applications ...

Page 19: ...has an insert point insert the compressor there If you don t have an insert point you will have to place the compressor after your mixer s bus output or whichever output you re using by coming out of your mixer to the input of the ACP 22 then out of the ACP 22 to the input of your recorder If you re using a stand alone mic preamp patch the ACP 22 after the preamp and then to the recorder Turn the ...

Page 20: ...ercussion instruments Limiting the dynamic range of a drum kit may or may not be something you want to do to your drum tracks but there are some other cool things the ACP 22 can do to make your drums really happening If you think about how a snare drum sounds it has a beginning loud sound followed by a usually short decay Patch a channel of your ACP 22 for compressing the snare drum as described a...

Page 21: ...ing for the level of a signal On your ACP 22 limiting occurs when the ratio knob is fully clockwise At this point the threshold knob essentially becomes the ceiling knob for the channel You will most likely want an instantaneous attack time while limiting To achieve this Make sure the auto button is out Turn the attack time knob fully counter clockwise and set the compressor s release time for the...

Page 22: ... of the spare channel and send it to the sidechain input of the ACP 8 signal on the ring of the tip ring sleeve connector Once patched setup the compressor as a limiter as described above How this works is that when the sidechain has an inserted signal the compressor generates the gain reduction from the sidechain return signal only Now if you boost those frequencies associated with sibilance SSS ...

Page 23: ...Basic Setup Applications will eliminate all gain reduction and effectively turn off the gain reduction meters The gain reduction is of course being derived from the master channel ...

Page 24: ... to 60dB Input Impedance 10kOhms Output Impedance 51 Ohms THD Noise 0 02 Output Gain 20dB to 20dB Compression Curve Types Soft Knee or Hard Knee Compressor Metering Above and Below Threshold Gain Reduction Gate Metering Open and Closed Sidechain Output Impedance 51 Ohms Sidechain Input Impedance 10kOhms Gate Input Impedance 10kOhms Internal Operating Level 4dBu 0dB Input Range 4dBu or 10dBV Switch...

Page 25: ...or vocal making it easier to record without distorting the recorder It also assists in the mixing process by reducing the amount of level changes needed for a particular instrument Take for example a vocalist who moves around in front of the microphone while performing thus making the output level vary up and down unnaturally A compressor can be applied to the signal to help correct this recording...

Page 26: ...has a wide dynamic range Transients the very loudest portion of the signal can be far outside the average level of the vocal signal It is extremely difficult to ride the level with a console fader A compressor limiter automatically controls gain without altering the subtleties of the performance A solo guitar can seem to be masked by the rhythm guitars Compression can make your lead soar above the...

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