ACP88 Eight Channel Compressor/Limiter/Gate User’s Manual Version 1.
ACP88 E I G H T C H A N N E L C O M P R E S S O R / L I M I T E R / G A T E USERSMANUAL Version1.2 Copyright 1998,2000,2001 PreSonus Audio Electronics, Incorporated. All rights reserved.
W A R R A N T Y PreSonus Limited Warranty PreSonus Audio Electronics Inc. warrants this product to be free of defects in material and workmanship for a period of one year from the date of original retail purchase. This warranty is enforceable only by the original retail purchaser. To be protected by this warranty, the purchaser must complete and return the enclosed warranty card within 14 days of purchase.
TABLE OF CONTENTS 1 Overview 1.1 Introduction 1.2 Features 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 3 Controls&Connections Front Panel Basic Layout Compressor Controls Gate Controls Gain Bypass & Link Patch Panel Power BasicSetupandApplications 3.1 Some Basic Patching 3.2 Basic Applications 4 Technical 4.1 Specifications 4.
OVERVIEW 1.1 INTRODUCTION Thank you for purchasing the PreSonus ACP-88 multi-channel dynamics processor. Your processor was designed using state of the art components to deliver crystal clear compression and noise gating for an infinite period of time. We believe the ACP-88 to be an exceptional sounding unit and an exceptional value. Feel free to contact us at 1-800-750-0323 anytime for any reason. We value your suggestions and your comments.
OVERVIEW drum kit, clean up a noisy tape machine, isolate an instrument or separate a vocal from background noise. Each noise Gate provides control over Attack, Threshold, Release and Gate close Range. The Gate close range can be useful in creating a more natural sounding blend or mix when gating many instruments at once. ? Comprehensive Channel Linking. Using the Link function allows you to combine any combination of ACP-88 channels effectively forming a subgroup.
OVERVIEW ? Separate Gate Sidechain/keying Jacks for Each Channel. Your ACP-88 also includes a separate jack on each channel for Gate sidechain/Keying. This is useful for synching an external sound to a snare track, for example, or putting equalizers or filters before the Gate key to enable Gating only the lower frequency of a kick drum, etc. ? Balanced/Unbalanced Inputs and Outputs. Your Acp-88 accepts either balanced or unbalanced inputs and outputs using tip-ring-sleeve (TRS) connectors.
OVERVIEW To Get Help… Call Us: 1-800-750-0323, 9 AM to 5 PM, CST Visit our World Wide Web Site: http://www.presonus.com Email Us: presonus@presonus.
CONTROLS & CONNECTIO NS 2.1 Front Panel Basic Layout Notice that the front panel is divided into eight identical sections. These are the eight signal processing chains of the ACP-88.
CONTROLS & CONNECTIO NS 2.2 Compressor Controls Threshold The Compressor Threshold sets the level at which compression begins. The below and above LED’s over the Threshold knob indicate whether the input signal is below or above the Threshold setting. When the signal is above the Threshold setting, it becomes ‘eligible’for compression. Basically, as you turn the Threshold knob counter-clockwise, the input signal is compressed. (If you have a ratio setting of greater than 1:1.
CONTROLS & CONNECTIO NS Threshold knob set at 0 dB, and the Ratio turned fully clockwise, the Compressor becomes a Limiter at 0 dB. This means the signal will be limited to an output of 0 dB regardless of the input signal. Attack Attack sets the speed at which the compressor ‘acts’on the input signal.
CONTROLS & CONNECTIO NS Soft The Soft button selects Soft Knee and Hard Knee compression curves. When this button is pushed in, Soft knee compression curves are used, otherwise hard knee compression curves are used. With Hard knee compression, the gain reduction applied to the signal occurs as soon as the signal exceeds the level set by the threshold.
CONTROLS & CONNECTIO NS 2.3 Gate Controls Attack The Gate attack control sets the speed at which the gate opens to allow signal to pass through it. This control is variable from 10 microseconds to 100 milliseconds. It is advisable to use slower Attack times when gating vocals or quieter instruments to avoid what is often described as gate ‘clicking’.
CONTROLS & CONNECTIO NS signals below the Threshold setting are reduced in level by the amount set by the Range switch. The ‘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. Release The Gate Release time determines the rate at which the gate closes. This is indicated by observing the OPEN and CLOSED LED’s.
CONTROLS & CONNECTIO NS 2.4 Gain Gain When compressing a signal, Gain reduction usually results in an overall reduction of level. The Gain control allows you to restore the loss in level which occurs due to the amount of compression used. (like readjusting the volume.) 2.5 Bypass & Link Bypass Activating the Bypass effectively removes all processing being performed by your ACP-88 and returns the signal to unity gain.
CONTROLS & CONNECTIO NS (presence or lack of signal), all metering should be referred to the Master channel’s meter for the Gain reduction level of the Linked channels! 2.6 Patch Panel (Back) Input The Input jack accepts balanced tip-ring-sleeve or unbalanced tipsleeve connectors. The Input can handle up to +24 dBu unbalanced or up to +18 dBu balanced signal levels.
CONTROLS & CONNECTIO NS Output The output jack accepts balanced tip-ring-sleeve or unbalanced tipsleeve connectors. The output will deliver up to +24 dBu in signal level, balanced or unbalanced. +4/-10 Switch This switch adjusts the internal operating level of your ACP-88 when it is connected to line level (0 dB = -10 dBV) gear. With this switch in the ‘-10’ position, the signal is adjusted by 11.2 dB so that it can be processed at the lower noise floor of your ACP-88’s internal circuitry.
CONTROLS & CONNECTIO NS connector. This signal can then be processed by an equalizer for example to reduce sibilance 9de-essing) in a vocal track. The signal is then returned to the unit via the tip of the connector. The signal sent via the ring could be that of a narrator or vocalist. In this application, the audio that you are passing through the compressor will automatically ‘duck’when the narrator speaks or vocalist sings.
CONTROLS & CONNECTIO NS 2.7 Power Power Connection The power jack on your ACP-88 accepts a standard IEC cord like those found on most computers and professional recorders. Your ACP-88 contains a custom built; internal power supply, no wall wart. This way you can be assured of clean power and rugged construction that will last! Power Selection Before powering up your ACP-88 for the first time, be sure to check the position of the power selector switch on the back of the unit.
BASIC SETUP & APPLIC ATIONS 3.
BASIC SETUP & APPLIC ATIONS Between multi-track recorder inputs/outputs to mixer outputs/inputs, unbalanced.
BASIC SETUP & APPLIC ATIONS 3.2 Basic Applications Example setup compressing a voice or vocal track. Probably the most common use of a compressor is to control the dynamic range of a vocalist during a live performance or when recording. It is almost always necessary to compress a vocal take during a recording session.
BASIC SETUP & APPLIC ATIONS out, Gate Threshold knob is fully counter-clockwise, 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.
BASIC SETUP & APPLIC ATIONS Attack knob clockwise. You should notice that the beginning 'transient' of your snare sound is starting to jump out of the speakers and slap you in the face. This becomes even more noticeable when using digital reverberation on the snare. Now you can adjust the Gate on the snare to stop those other drums from 'bleeding' through the snare mic: Begin by adjusting the Attack time of the Gate to .01(10 microseconds) by turning the Gate Attack control knob fully counter-clockwise.
BASIC SETUP & APPLIC ATIONS Compressing bass guitar. Very similar to compressing vocals, the bass guitar is almost always compressed or limited during recording. Start with the setting described above for vocals. Vary the Compression Ratio, Attack and Release to suite your taste. Compressing acoustic guitar. It is sometimes easy to over compress an acoustic guitar because your first impression is that compression sounds awesome on acoustic instruments.
BASIC SETUP & APPLIC ATIONS such as 2kHz to 8kHz, the Compressor will apply the Gain reduction more to the sibilance because it is now 'seeing' more signal around the frequency of the sibilance. You will need to adjust the frequency of the equalizer to locate your source of sibilance more precisely. Parametric equalizers are most effective for this type of compression but you can get by with most any equalizer. Stereo Compressing/Limiting.
TECHNICAL 4.1 Specifications Number of Channels..................................................................8 Dynamic Range........................................................................>115dB Signal to Noise Ratio.................................................................>95dB Headroom ............................+24dBu, Unbalanced; +18dBu Balanced Frequency Response ...................................................10Hz to 50kHz Crosstalk ..............................................
TECHNICAL
