background image

Controls & Connections 

 

'CLOSE' LED above the 

threshold

 knob indicates when the gate is closed 

(the signal level is 

below

 the 

threshold

). If the 

threshold

 is set fully 

counter-clockwise, the gate is turned off (always open), allowing all signals 
to pass through unaffected. 
 

Attack 

       The gate attack time setting determines the rate at which the gate opens. 
Faster attack times are normally useful for gating percussive instruments 
such as drums, etc. Slowing the attack time will eliminate any 'pops' are 
'clicks' in the gate when gating vocals, instruments, etc. 
 

Release 

       The gate release time determines the rate (speed) at which the gate 
closes. This is indicated by observing the OPEN and CLOSE LED's. As the 
release time is lengthened (clockwise), you will notice 
 
that the CLOSE LED reflects the close time. Release times should typically 
be set so that the natural decay of the instrument or vocal being gated is not 
affected. Shorter release times help to clean up the noise in a signal but care 
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), the signal 
will be gated (reduced) by 60dB as it crosses below the 

threshold

. If the gate 

range button is out (led off), the signal will be 

gated

 (reduced) by 6dB as it 

crosses below the 

threshold

. The CLOSE LED above the 

threshold

 knob 

indicates this by changing brightness relative to the range amount. When the 
range is set to 60dB, the CLOSE LED will illuminate to its brightest level at 
the end of the release time which has been set by way of the release control. 
 

Filter 

        The filter feature of your ACP-22 modifies the audio signal such that 
the gate is less sensitive to high frequency instruments. This means that when 
the filter is active, the gate will only open for those instruments with lower 
frequencies. The filter is set for -6dB at 2.5kHz. The filter rolls off the high 

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...

Reviews: