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ACP88
Eight Channel
Compressor/Limiter/Gate
User’ s Manual
Version 1.2
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ACP88 EIGHT CHANNEL COMPRESSOR/LIMITER/ G AT E USERS MANUA L Version 1. 2 Copyright 1998,2000,2001 PreSonus Audio Electronics, Incorporated. All rights reserved.
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WARRANT 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. During the warranty period PreSonus shall, at its sole and absolute option, either rep
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TABLE OF CONTENTS 1 Overview 1.1 Introduction 1.2 Features 2 Co ntrols & 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 and Applications 3.1 Some Basic Patching 3.2 Basic Applications 4 Technical 4.1 Specifications 4.2 Block Diagram
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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. PreSonus Audio Electronics is committed t
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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. When linked, all pr
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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) connect
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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.com 8
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CONTROLS & CONNECTIONS 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. Each channel contains: ? Compressor/Limiter ? Noise Gate ? Gain Makeup ? Link & Bypass Control 9
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CONTROLS & CONNECTIONS 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.) Rat
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CONTROLS & CONNECTIONS 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. 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 a
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CONTROLS & CONNECTIONS 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. With Soft knee compression, the onset of gain reduction occurs gradually after the signal has exceeded the Threshold, producing a more musi
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CONTROLS & CONNECTIONS 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’ . This phenomena is not made by a mechanical device in the noise gate, but is rather, an audible manifestation of ‘ no signal’ to the pres
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CONTROLS & CONNECTIONS 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 an
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CONTROLS & CONNECTIONS 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. You should use Bypass often when setting up your ACP-88 to compare t
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CONTROLS & CONNECTIONS (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 tip- sleeve connectors. The Input can handle up to +24 dBu unbalanced or up to +18 dBu balanced signal levels. 16
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CONTROLS & CONNECTIONS Output The output jack accepts balanced tip-ring-sleeve or unbalanced tip- sleeve 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 cir
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CONTROLS & CONNECTIONS 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. Gate Sidechain/Key Insert The Gate sidechain jack accepts a
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CONTROLS & CONNECTIONS 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. Make cer
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BASIC SETUP & APPLICATIONS 3.1 Some Basic Patching Inserting into your mixers insert points
