User manual SAMSON CCOM16

C Class Signal Processors PRE-SET STEREO COMPRESSOR Safety Instructions Caution: To reduce the hazard of electrical shock, do not remove cover or back. No user serviceable parts inside. Please refer all servicing to qualified personnel. WARNING: To reduce the risk of fire or electric shock, do not expose this unit to rain or moisture. The lightning flash with an arrowhead symbol within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the products enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. Important Safety Instructions 1. 2. 3. 4. 5. 6. 7. 8. 9. Please read all instructions before operating the unit. Keep these instructions for future reference. Please heed all safety warnings. Follow manufacturers instructions. Do not use this unit near water or moisture. Clean only with a damp cloth. Do not block any of the ventilation openings. Install in accordance with the manufacturers instructions. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or third prong is provided for your safety. When the provided plug does not fit your outlet, consult an electrician for replacement of the obsolete outlet. Protect the power cord from being walked on and pinched particularly at plugs, convenience receptacles and at the point at which they exit from the unit. Unplug this unit during lightning storms or when unused for long periods of time. Refer all servicing to qualified personnel. Servicing is required when the unit has been damaged in any way, such as power supply cord or plug damage, or if liquid has been spilled or objects have fallen into the unit, the unit has been exposed to rain or moisture, does not operate normally, or has been dropped. 10. 11. 12. Table of Contents Introduction C com 16 Features 2 3 Controls and Functions Front Panel Layout Rear Panel Layout Quick Start Set-Up Default positions Operating the C com 16 Connecting the C com 16 Setting Input and Output Levels Using the PROGRAM Pre-sets Operating the C com 16 in MANUAL mode Compressing a Signal in Manual Mode Using the Enhancer Key Insert Dynamics Processing 101 Applications System Set-ups C com 16 Wiring Tilting and Stacking the C com 16 C Class Dual Rack Adaptor (optional) Specifications Block Diagram 4 5 6-7 6 7 8 8 8-9 9-10 10-11 11 12 12 13-14 15 16 17 18 19 20 21 Copyright 2003, Samson Technologies Corp. Printed Febraury, 2003 Samson Technologies Corp. 575 Underhill Blvd. P.O. Box 9031 Syosset, NY 11791-9031 Phone: 1-800-3-SAMSON (1-800-372-6766) Fax: 516-364-3888 www.samsontech.com 1 Introduction Congratulations on purchasing the C com 16, pre-set stereo compressor by Samson Audio! The C com 16 is a compact, high-quality device that provides extensive dynamics processing and control that has previously only been found in expensive outboard devices. The C com 16 is the easiest to operate compressor ever made. Period! The easy operation makes the C com 16 the perfect solution for dynamics processing in live sound, and also, particularly for tracking in recording situations. With the 15 factory programmed Dynamics Pre-sets covering a wide range of applications, it's simple to dial up a dynamics program that's perfect for your gig or project. And for you tweekazoids, there is a full Manual mode offering variable control for Sensitivity, Ratio, Attack and Release. The C com 16 lets you add a powerful ENHANCER circuit to any Pre-set, or in manual mode, adding a pleasant restoration of high frequencies that can sometimes be diminished during heavy gain reduction. To help you monitor and set the best levels, the C com 16 features easy to read five segment, LED bar VU meters for INPUT and OUTPUT level, as well as GAIN REDUCTION. Like all Samson Audio C class processors, the C com 16 can be stacked on other C class models, and can be set up on an angle using the included tilting feet. The C com 16 is also a half-single rack space unit and can be rack mounted using the Samson CRK2 dual rack-mount adapter. Most importantly, by providing transparent gain control and superb audio fidelity, the C com 16's signal path will impress the most critical listeners. Although this unit is designed for easy operation, we suggest you take some time out first to go through these pages so you can fully understand how we've implemented a number of unique features. In this manual, you'll find a more detailed description of the features of the C com 16, as well as a guided tour through the front and rear panels, step-by-step instructions for using the C com 16 and full specifications. You'll also find a warranty card enclosed--please don't forget to fill it out and mail it so that you can receive online technical support and so we can send you updated information about other Samson products in the future. With proper care and adequate air circulation, your C com 16 will operate trouble free for many years. We recommend you record your serial number in the space provided below for future reference. Serial number: Date of purchase: Should your unit ever require servicing, a Return Authorization number (RA) must be obtained before shipping your unit to Samson. Without this number, the unit will not be accepted. Please call Samson at 1-800-3SAMSON (1-800-372-6766) for a Return Authorization number prior to shipping your unit. Please retain the original packing materials and if possible, return the unit in the original carton and packing materials. 2 C com 16 Features The Samson C Com 16 dynamics processor utilizes the latest technology in gain management design. Here are some of its main features: · Full featured, stereo dynamics processor with 15 Pre-sets covering a full range of typical compression jobs for live sound and recording. User programmable MANUAL mode with variable control of SENSITIVITY, ATTACK, RATIO, RELEASE and OUTPUT. Selecting a pre-set PROGRAM is easy by using the 16-position, rotary PROGRAM selection control and the dual color LED's with legends indicating the selected dynamics program. SKD (Smart Knee Detector) switches from soft to hard knee based on the level of input signal. AEG (Automatic Envelope Generator) mode constantly adjusts the Compressor's Attack and Release times based on input signal. Manual adjustment of Attack and Release time is also facilitated. Enhancer circuit to help restore high frequencies that are sometimes lost as a result of heavy gain reduction. 6 Segment LED Input/Output Meter, plus 6 Segment LED Gain Reduction Meter. External KEY insert point provides for external processing of the side chain signal. High quality variable resistors provide smooth control. Easy to read and operate LED, backlit push switches. +4 and ­10dBu operating levels can be selected using the OUTPUT LEVEL switch. Advanced electronics incorporating high quality VCA's and low noise op-amps providing a transparent signal path. Oversized, rubber bumpers with tilting feet allow several Samson C class units to be stacked and tilted in an ergonomically correct operating position. EIA standard 19" rack mounting using the optional CRK2 rack mount kit. The stylish bead blasted, electric blue anodized front panel is as easy to read as it is to look at. Three-year extended warranty. 3 · · · · · · · · · · · · · · · C com 16 Front Panel Layout C com 16 Front Panel Layout 1 PROGRAM LED'S 1- 8 ­ When illuminated, indicates the associated Program (1-SMOOTH VOCAL, 2AGGRESSIVE VOCAL, 3-BASS, 4-SLAP BASS, 5ACOUSTIC, 6-FUNK GUITAR, 7-SUSTAIN, 8-PERC 1) is selected. PROGRAM LED'S 9-16 ­ When illuminated, indicates the associated Program (9-PERC 2, 10-SOFT, 11-DYNAMIC, 12-ENHANCED, 13-STEREO COMP, 14­STEREO LIMIT,15-STEREO MASTER,16-MANUAL) is selected. PROGRAM SELECTOR ­ Rotary encoder control knob used to select the 16 Programs. GAIN REDUCTION METER - Displays the amount of Gain Reduction when Compressor circuit is activated. SENSITIVITY - Used to set the minimum signal level at which the Compressor circuit begins to function. RATIO - Controls the amount of Gain Reduction in proportion to the amount of signal over the selected threshold level. RELEASE - Selects the amount of time the compresssor takes to return the signal to the orignal level. 8 OUTPUT - Used to set the final level after the compression circuit is applied. INPUT/OUTPUT METER - Six segment LED meter displays the Input or Output signal level based on the settings of the I/O meter switch. 9 2 10 MAINS POWER SWITCH - When switched on, the green LED will light, indicating the C com 16 is powered on and ready for operation. 11 ENHANCER - Activates the C com 16's Enhancer circuit which restores the high end loss resulting from extreme Gain Reduction. 12 ATTACK - Adjusts the amount of time the compressor takes to reach full gain reduction. 13 BYPASS - Used to switch the C com 16's compression circuit on and off. The C com 16 is engaged when the BYPASS LED lights green. 14 INPUT/ OUTPUT METER SELECT SWITCH - Selects either Input or Output level to be displayed on the Input/Output Meter. 3 4 5 6 7 4 C com 16 Rear Panel Layout C com 16 Rear Panel Layout A AC INLET - The included AC power supply is connected here. B LEFT OUTPUT - 1/4-inch, TRS (TIP/RING/SLEEVE) E KEY INSERT ­ 1/4-inch TRS (TIP/RING/SLEEVE) phone input/output connector used to externally process the compressors trigger signal. F LEFT/MONO INPUT - 1/4-inch phone connec- phone connector for the LEFT line-level, balanced output. C RIGHT OUTPUT - 1/4-inch, TRS (TIP/RING/SLEEVE) phone connector for the RIGHT line-level, balanced output. OPERATING LEVEL SWITCH - Switches the operat- tor for the LEFT (in stereo operation) or MONO line-level inputs. G RIGHT INPUT - 1/4-inch phone connector for the RIGHT line-level input. D ing level from -10dB to +4dB. 5 QUICK START Quick Start - Set-up Setting up your C com 16 is a simple procedure, which takes only a few minutes. There are many ways to interface the C com 16 with various recording or live sound set-ups, so take some time to decide which audio devices you want to connect. The following section shows a simple set-up for a typical live sound system with a C com 16 connected to a mixer, CD player and two powered PA monitors. Remove all packing materials (save them in case of need for future service) and plug the provided AC adapter in to the rear AC power inlet, but don't plug the power pack into a wall outlet just yet. You can use the C com 16 in line with the output of a mixer or recorder, or in a send and return insert-point which is typically found on input and output channels of mid to larger mixers. For detailed wiring diagrams see page 17 of this manual. Follow the next few steps described in the section below to begin to use your C com 16. Note: Before plugging in and turning on, remember the "last on, first off" rule of power amplifiers and powered speakers. When powering up your system, be sure that all the wires are connected, turn your mixer and any other outboard gear on, and then last, turn your power amplifier or powered speakers on. When powering down, turn your power amplifier or powered speakers off first and then your mixer and outboard gear. LEFT/MONO LEFT LEFT AUX OUT AUX RET CR OUT MIX OUT 30 30 3/L LINE IN 5/L LINE IN RIGHT RIGHT RIGHT MONO OUT GAIN CLIP GAIN CLIP 5 -26 +26 60 5 -26 +26 60 4/R 6/R 0 5 5 0 0 5 0 5 HF 12K 5 HF 12K 5 HF 12K 5 5 HF 12K 10 10 10 10 10 10 10 10 15 5 0 15 5 2.5K 10 15 0 15 5 2.5K 10 15 0 15 5 2.5K 10 15 0 15 5 2.5K 10 5 MF 5 MF 5 MF 5 MF 2T IN 2T OUT 10 10 10 10 15 5 0 15 5 80Hz 10 15 0 15 5 80Hz 10 15 0 15 5 80Hz 10 15 0 15 5 80Hz LEFT LF RIGHT LEFT RIGHT 0 MONO 10 LF 5 LF 5 LF 5 2TK TO MIX 10 10 10 10 10 5 15 15 15 15 15 15 15 15 AUX AUX AUX AUX 0 10 0 0 10 0 0 10 0 0 10 0 0 10 AUX RETURN 5 PAN PAN BAL BAL L R L R L R L R 0 10 MIX/2T _ _ _ _ _ _ _ _ C/ROOM +PHONES 5 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 0 10 · Using standard 1/4-inch cables, connect the mixer's left and right OUTPUTS to the to the C com 16's LEFT and RIGHT INPUTS. Now, using standard cables connect the C control's LEFT and RIGHT OUTPUTS to the inputs of your power amp or powered monitors. · 6 QUICK START Quick Start - Set-up - continued · · Plug the C com16's power pack into a wall outlet and switch the unit on by pressing the power switch. Next, turn on your mixer, but don't turn on your power amp or powered monitors just yet. Quick Start - Default Position · Set the controls to the following default positions: PROGRAM SELECTOR ­ 16 MANUAL SENSITIVITY ­ -40 (fully counter-clockwise) RATIO ­ 1:1 ATTACK ­ 0.3 (fully counter-clockwise) RELEASE -5 (fully clockwise) METER SWITCH ­ IN OUTPUT LEVEL ­ -20 dBu (fully counter-clockwise) ENHANCER SWITCH - OFF (LED off) BYPASS - OUT (LED off) Quick Start - Compressing Your Signal · Run a signal from your mixer, like music from a CD, to the inputs of the C com 16. Make sure that you are sending a good signal level by monitoring the mixers main output meters. Engage the C com16 by pressing the BYPASS switch so that the GREEN LED turns on. With the music playing, adjust the C com 16's SENSITIVITY level so that the INPUT METER reads between -6 and 0 dB. Once you have a good signal level set, turn off the signal (stop the CD) from the mixer. Now, set the power amp or powered monitor level to a relatively low level and power up. · · · · Note: In this default configuration, the C com 16 is simply passing audio at unity gain with no dynamics proceszing. It's a good idea to check your gain structure at this point. Use the Input/Output meter to match the level. · · Press the METER switch to see that the input and output levels are matched. Once you have set a good gain structure you can begin to compress your signal. Using the PROGRAM selector knob, rotate through the pre-sets until LED number 13 turns GREEN, indicating the STEREO COMP pre-set is selected. At this point the C com16 will be compressing the signal from your mixer. You may notice activity on the GAIN REDUCTION meter, which displays the amount of level the signal is attenuated. Now, you can experiment with raising the SENSITIVITY a bit and raising the OUTPUT level some. By raising the SENSITIVITY level you are adding more compression so the level may drop. Use the OUTPUT level control for getting back to the unity gain (the same level), with the BYPASS in or out. 7 Operating The C com 16 Connecting the C com 16 The C com 16 can be easily connected to most any audio device thanks to the use of standard 1/4-inch phone connectors, and to the +4/-10 switch input level switch. You can use your C com 16 in a mixers insert point, or in-line between your instrument or other line level audio device. Once you decide what signal you will be connecting to your C com 16, you can choose your wiring and level setting. To do this, follow the sections below. For a detailed wiring diagram, see page 17 of this manual. 1 STEREO INPUTS The rear panel STEREO INPUTS use 1/4-inch connectors for the line level inputs. A mono signal can be inserted into the LEFT/MONO Input, and that signal will be split and sent the RIGHT input so that the STEREO OUTPUTS will have the same signal on both the LEFT and RIGHT OUTPUTS. 1 2 +4/-10 Switch The +4/-10 switch located on the rear panel is used to adjust the C com 16's input to the best operating level for the device that you are connecting. Press the +4/-10 switch to the -10 position when connecting signals from instruments like guitars and bass guitars, or for consumer audio devices like CD, MD and Cassette player/recorders. Press the +4/-10 switch to the +4 position when connecting to the insert-point of a mixer, or to pro audio gear like effects processors and recorders. 2 -10 +4 3 STEREO OUTPUTS On the C com 16's rear panel you will find the STEREO OUTPUTS which are 1/4-inch TRS (TIP/RING/SLEEVE) connectors carrying the balanced line level outputs. If a 3 mono signal is inserted into the LEFT/MONO Input, that signal will be split and sent the RIGHT input so that the STEREO OUTPUTS will have the same signal on both the LEFT and RIGHT OUTPUTS. Setting Input and Output Levels RIGHT The C com 16 is capable of handing a variety of input signals ranging from low level guitar/instrument signals, through -10dBV line level signals from consumer audio gear, all the way up to +4dBu signals from pro audio devices. Whether you are using one of the C com 16's powerful internal pre-set PROGRAMS or using the MANUAL mode to dial up your own sound, it's important to set a good input and output level in order to maintain the best quality signal. The following section details the various controls and meters used to set a good input and output level. 4 I/O METER The I/O meter is a six segment LED display which can be set to show the INPUT or OUTPUT level, depending on the position of the METER switch. The I/O meter displays the 4 level in a dB scale from OL (OVERLOAD), +6, 0, -6, -18 and -30. 5 METER Switch The METER switch is used to assign either the INPUT or OUTPUT signal to the I/O meter. Press the switch to the OUT position to monitor the C com 16's OUTPUT level. Since you will adjust the input level first, place the METER switch to the IN position. 5 8 Operating The C com 16 Setting Input and Output Levels - continued 6 SENSITIVITY It is important to undertstand how the C com 16's SENSITIVITY control works since it has a dual purpose. First, to control the input level, and second, to control the relative threshold level for the comressor cicuit. The C com 16 has a fixed threshold level and by using the SENSITIVITY control you can adjust the relative threshold level and thereby the total amount of gain reduction. Slowly raise the SENSITIVITY control, and monitor the INPUT LEVEL meter until you reach the desired amount of level and the INPUT METER reads between -6 and 0. 6 7 GAIN REDUCTION METER The GAIN REDUCTION meter is a six segment LED display showing the amount of gain reduction in dB's with a scale of 1, 3, 6, 12, 24 and 30. 7 8 OUTPUT Once you have set the amount of gain reduction using the SENSITIVITY control and GAIN REDUCTION METER, you can use the OUTPUT control to set the desired OUTPUT level. Sometimes called `make-up gain", the OUTPUT control will let you get back to the same level signal that was at the input before the application of gain reduction. Slowly raise the OUTPUT control, and monitor the I/O meter until you reach the desired amount of output level. Use the I/O meter and the BYPASS switch to check the gain. By switching the BYPASS in and out, you can check to see if the level is matching, and compare the sound with the compression on or off. 8 Now that you have the basic input and output level set, you can raise the SENSITIVITY control to "squeeze" the signal and add more compression. If necessary, use the OUTPUT contol to add and "make-up gain" that you may need to get back to the same output level after the compresson. Use the I/O and GAIN REDUCTION Meters to monitor the signal levels. Using the Program Pre-sets Your C com 16 comes pre-programmed with 15 extremely useful pre-sets covering many common compression applications. It's simple to get great compression on your sound just by dialing up a preset and adjusting the levels. When you select a pre-set using the PROGRAM selector, the C com 16 automatically adjusts all the compressor's control parameters to a factory pre-set level. Keep in mind that while the Program pre-sets are labeled for typical use, you may find that a Program works well for an entirely different application. As always, experience is the best teacher, so don't be afraid to experiment with different Program presets on any sound and let your ears decide. Use the BYPASS switch to compare the sound in and out and if the sound is better with the C com 16 engaged, you've got it. 9 Operating The C com 16 Using the Program Pre-sets - continued 9 PROGRAM Control The PROGRAM control is used to select one of the 15 presets, or the MANUAL mode. When you dial through the pre-sets using the PROGRAM control, you will see the corresponding PRESET LED turn from RED to GREEN. · Follow the section above, "SETTING UP THE C Com 16" for normalizing the controls, and the section "Setting Input and Output Levels" to set the starting input and output levels. Press the BYPASS switch to the IN position so that the green LED is on. Using the PROGRAM control knob, select one of the following C com 16's Program pre-sets: 1 - SMOOTH VOCAL 2 - AGGRESSIVE VOCAL 3 - BASS 4 - SLAP BASS 5 - ACOUSTIC 6 - FUNK GUITAR 7 - SUSTAIN 8 - PERC 1 9 - PERC 2 10 - SOFT 11 - DYNAMIC 12 - ENHANCED 13 - STEREO COMP 14 - STEREO LIMIT 15 - STEREO MASTER 16 - MANUAL 9 · · Once you select the PROGRAM pre-set and you have the basic input and output level set, you can raise the SENSITIVITY control to "squeeze" the signal and add more compression. If necessary, use the OUTPUT contol to add and "make-up gain" that you may need to get back to the same output level after the compresson. Use the I/O and GAIN REDUCTION Meters to monitor the signal levels. Operating the C com 16 In MANUAL Mode In addition to the powerful pre-sets, the C com 16 can be used as a full featured standard compressor, where you dial up the controls to get your exact setting. 10 In MANUAL mode you will set the various parameter controls to create your own compression effect. The following section details the comression controls that you can set yourself in MANUAL mode. 10 RATIO The Ratio control sets the amount of compression from one to one, which is essentially no compression, to infinity to one, which is extreme peak limiting. The RATIO control is used to set the proportion of gain reduction in relationship to the input signal. For example, if the RATIO is set to 2:1 and the signal crosses above the threshold level, an increase in level of 2 dB will produce a 1 dB increase in level at the output. 11 11 ATTACK Use the ATTACK control to set the amount of time, from .3 to 300 milliseconds, that the C com 16's compressor takes to effect the gain reduction after the signal rises above the threshold level. 10 Operating The C Com 16 Operation the C com 16 In MANUAL Mode - continued 12 RELEASE The RELEASE control is used to set how long the compressor takes to return the input signal back to its original level once the signal falls below the threshold level. The C com 16's range for release time is from 50ms to 5 seconds. 12 Compressing a Signal in Manual Mode C Com16's compressor section can be used for a variety of gain management tasks including printing signals to a multi-track recorder, as a mix-down effect, mastering, and for increasing the loudness of a live PA system. To begin compressing your signal in MANUAL mode, follow the steps below: · · Use the PROGRAM control to select number 16; MANUAL. Follow the section above, "SETTING UP THE C Com 16" for normalizing the controls, and the section "Setting Input and Output Levels" to set the starting input and output levels. Press the BYPASS switch to the IN position so that the green LED is on. Adjust the Ratio to 2:1. Now, gradually turn up the SENSITIVITY level and listen for the compression. For a visual representation, the amount of compression is indicated on the GAIN REDUCTION meter. Press the METER switch to the OUT position. Now, by using the I/O METER and BYPASS switches, adjust the OUTPUT level to make up the gain and match the original signal. Experiment with manually controlled ATTACK and RELEASE times. · · · · · · Once you have set the basic input and output level and the RATIO, ATTACK and RELEASE controls in MANUAL mode, you can raise the SENSITIVITY control to "squeeze" the signal and add more compression. If necessary, use the OUTPUT contol to add any "make-up gain" that you may need to get back to the same output level after the compresson. Use the I/O and GAIN REDUCTION Meters to monitor the signal levels. 11 Operating The C Com 16 USING THE ENHANCER 13 ENHANCER The C Com 16's ENHANCER switch can be engaged to activate the EFR (Enhanced Frequency Recovery) circuit. By engaging the ENHANCER, the C Com 16 EFR restores the high frequency content that can be lost when high gain reduction is applied. The C Com 16 EFR achieves this by adding back the high-end of the original signal in an amount that is equal to the amount of gain reduction. · Follow the section above, "SETTING UP THE C Com 16" for normalizing the controls and run a signal such as a CD through the C Com 16. Set the PROGRAM switch to 13; STEREO COMP. Press the BYPASS switch to the IN position so that the green LED is on. Turn up the SENSITIVITY control until you reach 12 to 24 dB of gain reduction. Engage the ENHANCER switch and listen to how the high end is restored. · · · 13 · USING THE KEY EXT I/O INSERT JACK 14 KEY INSERT The C com 16 features a KEY insert jack which allows you to externally control the compressors trigger signal. Using the KEY insert jack, you can patch in an external processor to affect the compressors trigger. A typical application for external processing of the KEY signal is inserting a graphic equalizer to filter. The KEY insert jack is internally wired so the TIP is the KEY SEND and the RING is the KEY RETURN. 14 12 Dynamics Processing 101 To begin to understand dynamics processing, we must first understand what dynamics are. Dynamics, or the dynamic range of a signal or audio device, is the amount of level between the softest and loudest possible output. Dynamics processing is applied to a signal to manage the changes in level. Various types of processing units are available to control dynamics including Noise Gates, Expanders, Compressors, Limiters and De-Essers. All of these processes have a unique effect on a signal, but one common element they share is that in one way or another they control gain. Some dynamics processors control gain in a subtle way by slightly reducing how soft and loud a signal is, while others make drastic changes in gain like reducing the signal until it's off. Applications for dynamics processing can be categorized by two distinct groups; first, to treat a signal that has an unpredictable dynamic range and make it predictable, and second, to create a "sound" by squeezing out the dynamic range. Whether used for a live sound application, recording, mixing or mastering, dynamic processors like the C Com 16 are valuable tools for controlling gain. The following is a basic overview of dynamics processing and how it is used to improve the quality of recorded and live sound. COMPRESSOR A good compressor is one of the most useful tools in live sound and recording. Compressors are used to control the dynamic range of a signal, which offers a variety of benefits including leveling a signal that's being recorded, having an instrument sit in the mix, and increasing the loudness of a sound system to name a few. Drastic amounts of compression will also result in an effect that becomes more of a sound than just controlling gain. To understand how a compressor works, it is necessary to become familiar with the basic parameters which include threshold, ratio, attack time, and release time. Threshold Threshold is the level that once the signal exceeds, gain reduction is applied. The normal range of adjustment for the threshold level is ­40 to +20 dBu. If the threshold level is set above the highest level of the signal being sent to the compressors, the gain reduction is never triggered. Therefore, the compressor is virtually by-passed. If the threshold level is set very low so that any signal will trigger gain reduction, the compressor is working as an automatic leveler. Ratio The ratio control is used to set the proportion of gain reduction in relationship to the input signal. For example, if the ratio is set to 2:1 and the signal crosses above the threshold level, an increase in level of 2 dB will produce a 1 dB increase in level at the output. A ratio setting of to 1 means that an infinite amount of input signal is needed to raise the output level by 1 dB. This means that the output level stays constant even when the input crosses over the threshold level. Attack Time Attack time is the amount of time that a compressor takes to affect the gain reduction after the signal rises above the threshold level. A well-designed compressor has adjustable attack times ranging from 300 µs (microseconds) to 300 ms (milliseconds). A good compressor will sound smooth as it begins to control the gain regardless of the attack time. Release Time The release time is set to control how long the compressor takes to return the input signal back to its original level once the signal falls below the threshold level. The acceptable range for release time is from 50ms to 5 seconds. In normal use, faster release times are used for spoken word and longer release times are generally better for instrumental music. Auto Attack and Release Today, sophisticated compressors often incorporate a dynamic or Auto Attack and Release mode. The C Com 16's AEG (Auto Envelope Generator) is such a mode which automatically adjusts the attack and release time based on the dynamically changing input signal. 13 Dynamics Processing 101 - Continued Soft-Knee / Hard-Knee In order to prevent harsh, unnatural envelopes on compressed signals, sophisticated dynamics processors like the C Com 16 feature an SKD (Smart Knee Detector) or automatic knee circuit. The Smart Knee Detector automatically switches from Soft-Knee when the signal is less than 10 dB over threshold, to Hard-Knee when the signal is 10db above threshold. In Soft-Knee mode, there is a gradual affect on gain change, which begins as the signal approaches the threshold level. In Hard-Knee mode, gain reduction is linear based on the threshold and Ratio controls. Any signal that falls below the threshold level will be unprocessed. Noise Gates Noise gates are used to remove unwanted noise and/or bleed from recorded tracks in the studio or from open microphones in live sound systems. Noise gates can also be used as a sound effect, most commonly to chop the end of a reverb, let's say on a snare drum, so that the entire snare sound ends just before the beat. The basic principle of a noise gate is to work as an automatic mute switch. Mute off (Gate Open) when the desired signal is present and mute on (Gate Closed) when the desired signal is not present. In order to get the gate to work predictably, it is necessary to set a threshold, or trigger level that will determine when the gate will open. If the signal is below the trigger, the gate will remain closed. When the signal is above the trigger, the gate will trigger open allowing the desired signal to pass and be heard. Noise gates often have other adjustable controls like attack, hold, range and release. Many noise gates like those in the SAMSON S com, S com plus, S com 4 and S gate 4 use sophisticated circuits to control some of these parameters automatically. Downward Expander The purpose of a well-designed Downward Expander is to increase the perceived dynamic range of a system. This is accomplished by decreasing the gain during the softer sections, thereby lowering the relative noise floor. When the signal level is below the desired trigger level, the expander lowers the overall gain by the selected amount. Side Chain / External Key The C Com 16 features a side-chain or external Key function. The external Key function is used to externally process the compressor's detector circuit. There are many useful applications for processing the detector circuit including Equalizing for frequency dependent compression, De-Essing - the use of EQ to remove sibilance, and externally keying off a vocal track for Ducking effects, to name a few. The Key insert jack sends the compressors trigger signal for external processing, and then receives the processed signal, which will now control the compressor's detector. 14 Applications Leveling a Vocal Track When recording a vocal track, the vocalist may change the distance between them and the microphone, or they may naturally have a lot of dynamic range in their performance. In either case, the sound engineer must decide how much compression should be used to balance the natural performance and printing a good level to tape or disk. In PROGRAM mode you can use the PROGRAM pre-set, 1- SMOOTH VOCAL. In MANUAL mode, set up the C Com 16 with a medium attack and release time and a ratio of 4:1. Now adjust the SENSITIVITY level so that the Gain Reduction meters show 6 to 12 dB of gain reduction. Adjust the RATIO control if necessary. Leveling a Guitar or Bass Guitar and especially bass guitar can have a lot of level change between strings and even frets on the fingerboard. Using compression when recording guitars and bass will even out these differences. In PROGRAM mode you can use the PROGRAM pre-set, 3 - BASS. In MANUAL mode, set up the compressor section of the C Com 16 with a medium attack and release time and a ratio of 4:1. Now adjust the Threshold level so that the Gain Reduction meters show about 12 dB of gain reduction. You'll notice that each note is at the same loudness and the overall sustain is increased. Compressing Drums Adding compression on drums can make a boomy kick drum tighten up, almost as if you were tightening the head. In PROGRAM mode, select the PROGRAM pre-set, 8 - PERC 1. In MANUAL mode, set the C Com 16 to a fairly quick attack time and use a ratio of 6:1. Set the SENSITIVITY so that the Gain Reduction meter reads 12 to 24 dB. Adjust the RATIO control if necessary. You can use the same basic set-up on snare and toms as well. Getting a Track to Sit in the Mix By using a heavy amount of compression you can get the effect of the vocal suspending in the mix. While this may be a bit radical for some, the effect can be dramatic especially if the vocal is mixed without any reverb or delay. In PROGRAM mode, select the PROGRAM pre-set, 2 - AGGRESSIVE VOCAL. In MANUAL mode, set up the compressor section of the C Com 16 with a medium attack and release time and a ratio of 6:1. Now adjust the Threshold level to so that the Gain Reduction meters show 12 to 24 dB of gain reduction. Speaker Protection There are several ways to use a compressor to protect a speaker system and many considerations can be made whether the speaker system is crossed-over actively or passively. If the speaker system is stereo using a passive crossover, then the line output of the mixer or equalizer is run directly into the C Com 16 inputs. The C Com 16 should be last in the chain before the power amps with its outputs feeding the inputs of the amp. In PROGRAM mode select the PROGRAM pre-set,14 - STEREO LIMIT. In MANUAL mode, adjust the SENSITIVITY and RATIO so that the systems entire dynamic range is under control. 15 C Com 16 System Set-Ups LIVE SOUND SYSTEM WITH STEREO COMPRESSION In this example, the C Com 16 is inserted after the mixer and before the graphic equalizer, thereby compressing the full range signal from the mixer. COMPRESSION SUBGROUPS ON INSERT POINTS In this example, two C Com 16's are connected to the the mixer's insert points on the subgroup outputs. By assigning the channel inputs to the subgroups, you can individually compress a submix, such as the drums, and seperately compress a second submix, like the vocals channels, using the subgroup insert points. 16 C Com 16 Connections CONNECTING THE C Com 16 There are several ways to interface the C Com 16 to support a variety of applications. The C Com 16 features servo-balanced inputs and outputs, so connecting balanced and unbalanced signals is possible without any signal loss. The C Com 16 can be used on a single instrument by connecting to a channels insert points, or on an entire mix "in-line" between a mixer's outputs and a power amp or equalizer. INSERT POINTS Many mixers today provide channel and bus or group inserts. Insert points are input and output patch points that interrupt the channel or bus signal so that external processors can be connected. Channel insert points are ideal for connecting to when using the C Com 16 to process a single channel like a vocal, bass or guitar. Bus insert points are ideal for compressing groups of instruments like vocals, strings or drums. If you are connecting to a channel's insert points, you may have a single TRS jack for Send & Return. In this case, use an Insert Cable that is configured like the one in the wiring diagram below. Insert Cable 1/4" male TRS connector to two male 1/4" in send and return configuration. CONNECTING THE C Com 16 - continued IN-LINE In live sound operation the C Com 16 can be installed in-line between a mixer and equalizer or power amplifier. For these applications the C Com 16 provides both 1/4" TRS connectors connectors to easily interface with most any professional audio device. Follow the wiring examples below for your particular installation. 17 Tilting and Stacking the C com 16 Installing the Tilting Feet You can install the tilting rubber feet included with your C com 16 so that you can set the unit at a comfortable operating angle on a workstation or desktop. Follow the simple instructions below to install the tilting feet. · Remove the bottom screw from right front bumper. Identify the right tilting foot by the locating "R" marking on the inside top. Position the angled foot under the right bumper as shown in the drawing. Use the included 4 x 10mm screw to attach the foot. Repeat the steps above for the front left bumper. · · · · Stacking the C com 16 You can stack one C com 16, or any other Samson C Class units, on top of each other by simply lining up the bumpers. Important Note: When stacking the C COM 16, be sure that only the bottom unit has the tilting feet installed. 18