320A
Compellore lor ®®
Owner’s Manual
Dual Mono/Stereo Automatic Level Controller
Manual P/N 999-0760 • Revision 2 • 09/30/03
Copyright 2003 Aphex Systems Ltd. All rights reserved. Printed in U.S.A. Written and produced by Donn Werrbach.
S Y S T E M S
11068 Randall St., Sun Valley, CA 91352 U.S.A.
Fast Finderi
Contents |
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Quick Start |
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Introduction |
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3 |
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Installation |
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4 |
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Speci cations |
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5 |
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Operating Instructions |
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6 |
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System Description |
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7 |
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Warranty & Service |
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8 |
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Appendices |
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9 |
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Safety Declarations
CAUTION: For protection against electric shock, do not remove the cover. No user serviceable parts inside.
WARNING: This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the operating guide, may cause interference to radio communica - tions. Operation of this equipment in a residential area is likely to cause interference in which case the user will be required
to correct the interference at his own expense.
The user is cautioned that changes and modi cations made to the equipment without approval of the manufacturer could void the user’s authority to operate this equipment.
It is suggested that the user use only shielded and grounded cables to ensure compliance with FCC Rules.
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Conforms to standards |
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UL60950 and EN60950. |
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US |
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320A |
1. Contents |
Compellor
2.Quick Start - Page 6
3.Introduction - Page 7
3.1What Is A Compellor?
3.2What Does It Do?
3.3How Does It Work?
3.4A BIt Of Compellor History
4.Installation - Page 10
4.1Unpacking
4.2Damage & Claims
4.3Main Voltage Selection
4.4Power Cord
4.5Mounting In A Rack
4.6Proper Ventilation
4.7Panel Security
4.8Tools & Equipment Needed
4.9Safety Considerations
4.10Remote Connector
4.11Reference Level Setting
4.12Input Connections
4.13Output Connections
4.14Summary
5.Specifications - Page 14
5.1Inputs
5.2Outputs
5.3Audio
5.4System Functions
5.5Threshold
5.6Ratio
5.7Attack Times
5.8Release Times
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320A |
1. Contents |
Compellor |
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6.Operation - Page16
6.1Introduction
6.2Recording
6.3Mixing
6.4Mastering
6.5VIdeo Post Production
6.6Sound Reinforcement
6.7Live Concerts
6.8Broadcast Radio Pre-processing
6.9Broadcast STL/Phone Line Driver
6.10Television Broadcasting and Cable Systems
6.11Video and Audio Tape Duplication
6.12Voice Processing
6.13Hard Disk Recording
7.System Description - Page 20
7.1Model Differences
7.2Signal Flow
7.3Processing Functions
7.4Leveling Function
7.5Compressor Function
7.6DRC
7.7DVG
7.8Silence Gate
7.9Stereo Enhance
7.10Stereo Linking
7.11Meter Selection
7.12Limiter
7.13Process Balance
7.14Drive Control
7.15Output Control
7.16Process Switch
7.17Input/Output
7.18Operating Levels
7.19Input/Output Metering
7.20Gain Reduction Metering
8.Warranty & Service Information - Page 25
9.Appendices
Apndx A. Balanced & Unbalanced Lines and Operating Levels - Page28
Apndx B. Dealing With Grounds and Hum - Page 29 Apndx C. Proper Wiring Techniques - Page 31
Apndx D. Standard Cable Wiring - Page 32
Apndx E. About Reference Levels - Page 36
Apndx F. Digital-vs-Analog; Peak-vs-RMS: How To Deal With The Confusion - Page 38
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Page 5
320A |
2. Quick Start |
Compellor
You can use this quick setup to get a signal through your Compellor right away. Then. you’ll want to go on and read through the manual to discover the wealth of information that is available to you.
Quick Start
1. Make sure there is signal going through the Compellor with Process both “In” and “Out”. If not, check the input and output wiring. They may be reversed. Be sure to check for the correct input selection (analog or digital) on the rear panel. Leave Compellor in bypass (Process “OUT”) until finished with set up.
2.Send a zero VU tone into the
Compellor (at +4dBu or -10dBV depending on your operating level settings). Check to see the rear panel REF LEVEL switches are set for your operating level. If you do not have a tone generator, use program material that averages around zero VU in your system.
3.Switch Compellor “Meter Select” to Input. The last red LED should indicate approximately ‘0’ on the meter. If not, adjust the rear panel REF LEVEL switch to the position which gives you the closest reading to ‘0’.
4.Set the Process Balance to 12 o’clock.
5.Switch the Meter Select to G.R. (gain reduction). Adjust the Drive control to achieve 12dB of gain reduction with ‘0’VU input. The last lighted LED shows the total amount of gain reduction occurring.
6.Set Leveling Speed to Slow if you are controlling full program, Fast if you are controlling live voice.
7.Set Limiter “On”.
8.Set the Silence Gate to 12 o’clock.
9.Stereo Enhance: If using the Compellor for mono or dual mono operation, switch the
Stereo Enhance to “Off”. If using the Compellor for stereo program, switch the Stereo Enhance to “In”.
10.Link: If using the Compellor for mono or dual mono operation, press the “Unlink” button. If using the Compellor for a normal stereo program, switch the Link to “Leveling”. If using the Compellor for any matrixed stereo program (e.g.- surround encoded), switch the Link to
“Leveling & Compression”.
11.Switch the Meter Select to Output. Adjust the Output control so that the red part of the level meter indicates 0dB. Switch the Compellor into circuit (Process “In”). The Compellor will now act as a unity gain device whenever the input level is at zero VU, and make gain corrections for higher and lower incoming levels.
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3. Introduction
3.1 What Is A Compellor?
A Compellor is the first and only product designed specifically for the transparent control of audio levels. While other audio processors are designed simply to compress and limit audio signals, a Compellor is designed to intelligently manage the dynamic range of audio without causing noticeable changes to the character and feeling of the sound. Contained within the Compellor are three gain controllers: a frequency discriminate leveler, a compressor, and a limiter, all working interactively. In addition, a dynamic verification gate, silence gate, and dynamic release computer intelligently guide the operation of the gain controllers to assure the least noticeable processing effects will be generated.
The name “Compellor” is a combination of “Compressor-Leveler-Limiter”.
3.2 What Does It Do?
Simply stated, a Compellor automatically evens out the varying levels in an audio system without making itself noticed. It may seem odd to have a processor you wouldn’t notice working, but imagine being able to keep a wandering vocal track just right in the mix as if the talent were using perfect voice techniques. Imagine a TV show that always sounded just the right level even though scene changes were wide ranging. Now imagine these things without any background swells, pinched voices, or holes punched by a transient hitting the limiter. If you can, then you realize just a few things the Compellor can accomplish.
Without a Compellor, it is usual to insert a compressor or limiter in the line to control varying levels. That always results in degraded sound due to the processing by-products. Lost punch, overly fat backgrounds, inversion (when a loud sound gets lower than average), suck-down by transients, and noise swell ups are typical problems encountered with usual processing.
The Compellor was designed specifically to avoid all of these problems and more.
3.3 How Does It Work?
Standard compressors and limiters process the sound on arbitrary principles of level detection, something like an audio VU or peak meter. Our hearing is a much more complex process and we can readily hear the “attenuate and recover” effects caused by these simpler devices.
In contrast, a Compellor automatically detects and corrects the sound level according to how we hear, and therefore seems natural and relatively undetectable. The unique and patented circuitry in a Compellor resulted from years of experiments in audio processing and creates the only level controller on the market designed specifically to be as “transparent” to the ear as possible. Additional information about the processing circuits in a Compellor will be found in the various sections of this manual.
3.4 A Bit Of Compellor History
At first, there was a controversy about whether a Compellor actually did anything. Engineers would call up and complain they couldn’t hear the difference between “in” and “out” of the
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320A |
3. Introduction |
Compellor
circuit. They thought that all audio processors should be noticeable. We had to explain that the unit was in fact working, and we asked them to listen to their mixes with and without the Compellor. After they did that, they were amazed at the results. Meanwhile, broadcasters were discovering the Compellor. They found it greatly enhanced their air chains. The Compellor soon won the favor of broadcasters internationally.
Some owners may be interested in how the Compellor was first developed. The story begins in Hawaii in 1982 when Donn Werrbach, a consulting broadcast engineer, undertook to design an advanced AGC unit for on-air processing to improve the sound of radio stations. Werrbach
The Compellor has become the world standard audio level controller.
Understandably, we are very proud of that fact!
had been experimenting with broadcast audio processing for many years but needed to find a good enough VCA (voltage controlled amplifier chip) to fully implement all the new processing techniques he had discovered. A chance contact with Boyd Collings, who was then the Aphex agent in Honolulu, introduced Werrbach to the type 1537A VCA chip which was produced and sold by Aphex. Given a free sample, a couple of weeks time, and the inspiration brought by the VCA’s fabulous performance, Werrbach produced the first Compellor prototype.
Werrbach’s prototype found its way not only into on-air trials but into a tape duplicating lab, an album recording studio, and several live showrooms where it quickly proved its usefulness as a gain controller without processing artifacts. At Boyd’s urging, Aphex’s product manager
Jon Sanserino visited Honolulu and auditioned Werrbach’s prototype at the Audissey recording studio where he was intrigued by its possibilities. Finally, in 1983, an agreement was reached between Werrbach and Marvin Caesar, the president of Aphex Systems, to produce the Compellor as a product line.
The first unit rolled off the line in 1984 as the Aphex Model 300 Stereo Compellor. Patents were secured for key inventions of the Compellor circuitry and are assigned exclusively to
Aphex Systems.
As a premier product line, Aphex decided to build the Model 300 to the highest commercial standards including only the best available parts and construction techniques. As a result, not only is the audio processing performance outstanding, but the reliability and long lifetime of the product was assured. Thousands of Model 300’s are still in constant use today, some with as much as 19 years of duty under 24-hour service!
The next models introduced were the Models 301 and 303 based on the Model 300 design.
The Model 301 was a single channel version, while the Model 303 was a Model 301 with an Aural Exciter (tm) added. These models are also still in widespread use.
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In 1994, Aphex introduced the current Compellor Models 320A and 323A. The model “A” revision signifies the inclusion of an improved patented Leveler circuit called the “Frequency Discriminate Leveler” (FDL) while all other aspects of the Model 320 remain the same. With the FDL, Compellors became even more transparent and useful than ever before.
Now, in 2003 (as this manual is being written), the Compellor is still the most advanced and effective audio level controller available.
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320A |
4. Installation |
Compellor |
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4.1 Unpacking
Your Compellor was packed carefully at the factory in a container designed to protect the unit during shipment. Nevertheless, Aphex recommends making a careful inspection of the shipping carton and the contents for any signs of physical damage.
4.2 Damage & Claims
If damage is evident, do not discard the container or packing material. Contact your carrier immediately to file a claim for damages. Customarily, the carrier requires you, the consignee, to make all damage claims. It will be helpful to retain the shipping documents and the waybill number.
4.3 Mains Voltage Selection And Fuse
Before applying power to the Compellor, it is a good idea to verify the correct mains voltage setting. This is easily determined by looking through the transparent fuse cover on the rear of the chassis.
AC Line power is supplied to the unit via an integral receptacle/fuse holder on the rear panel. This receptacle meets the various international safety certification requirements, provides the international mains power selection, and serves as a radio frequency line filter. The programmed voltage can be read near the left end of the fuse clip on the surface of the programming card. If the incorrect voltage is seen, proceed to reprogram the voltage.
Reprogramming the mains voltage is easy if the following steps are followed. Remember to check the fuse value and install the correct fuse as indicated.
1. Slide window open |
FUSE |
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PULL |
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2. Pry out “Fuse Pull”
3. Extract programming card
Programming Card
Side 1 |
120 |
100 |
220 |
240 |
Side 2 |
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FUSE DATA
100-120VAC
0.375 Amp Slow Blow
220-240VAC
0.25 Amp
Slow Blow
4.Arrange correct voltage to read in this position. Fully re-insert the card by pressing firmly.
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4.4 Power Cord
The Compellor uses a standard IEC power cord set. The appropriate mains plug for each country is normally shipped with each unit. However, if you must install or replace the plug,
Power Cord |
Color Codes |
USA Color Code |
IEC/Continental Color Code |
Black = Hot (live) |
Brown = Hot (live) |
White = Neutral |
Blue = Neutral |
Green = Ground |
Yellow/Green = Ground |
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use the correct wiring code as follows:
4.5 Mounting In A Rack
The Compellor occupies one standard 19 in. x 1 3/4 in. rack space (1RU). Chassis depth is 9 1/2 inches not including connectors. Allow at least 3 inches additional space in back for wiring and connectors. The chassis is designed to be fully supported by front panel mounting alone. To avoid cosmetic damage to the panel, use the cushioned rack screws provided in the shipping kit or other cushioned rack screws.
4.6 Proper Ventilation
A Compellor runs warm because the product was designed to efficiently conduct most of the circuitry’s heat directly to the exterior surfaces. This keeps the hot internal components such as voltage regulators running far cooler than if they relied on direct convection cooling. Therefore, if the chassis seems unusually warm to the touch, you need not be alarmed since the inside of the chassis is never much warmer than that. However, we do not recommend installing a Compellor in a space which severely restricts air ventilation around the unit such as a totally sealed rack enclosure unless you can provide an empty rack space above and below the unit to facilitate cooling. Typical rack enclosures with louvers or fan cooling are recommended in which case you can install the Compellor in any available rack space.
4.7 Panel Security
A transparent security cover is available through any Aphex dealer to fit your Compellor. This is absolutely the most convenient way to protect your installation from tampering. When ordering, ask for Aphex part number SC-1.
4.8 Tools And Equipment Needed
Only standard technician’s tools are required to install the Compellor. Additional test equipment is required for servicing as will be indicated in the related sections of this manual.
4.9 Safety Considerations
Aphex has taken care to insure the safety of its products. The Compellor is constructed to comply with international electrical safety standards.
To minimize the risk of shock or fire, do not expose the unit to moisture. Allow adequate ventilation around the unit for cooling. Make sure the mains voltage is properly selected. Do not open the chassis cover: there are no user serviceable parts inside.
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320A |
4. Installation |
Compellor |
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Installation should be performed only by qualified individuals. It is the installer’s responsibility to insure his personal safety and the safety of others in the work area. It is never a good idea to work alone in the vicinity of high power electrical and radio frequency equipment.
4.10 Remote Connector
Remote control, a feature of the Models 320A and 323A.
4.11 Reference Level Setting
The Compellor should be normalized to match the operating level of your system. When the Compellor is properly matched to the system reference level, then the Compellor’s meters will match the system meters and the internal dynamic range of the Compellor will be optimized.
Normalizing the Compellor is accomplished by a rear panel REF LEVEL switch provided for each channel. Two standard reference levels of -10dBV and +4dBu are available. Simply set the switches as required.
If you have a nonstandard operating level, select the closest setting to your operating level.
For DAT machines and other digital media that define operating levels according to a maximum level rather than an average level, we have found the -10dBV position most often provides the correct match.
4.12 Input Connections
The input impedance is 20 kilohms and the Compellor will not significantly load the source when the unit is in-line. Inputs are made by means of 3-pin female XLR jacks. Pin connections follow conventional standards. Pin 1 is connected directly to chassis ground. Signal pins 2 and 3 may be used either as pin-2 positive or pin-3 positive as you wish. Current U. S. and international industry standards call for using pin-2 as the positive polarity lead.
For unbalanced use, tie pin 3 to pin 1 for the ground and use pin 2 as “hot”.
Whether using balanced or unbalanced wiring, be sure to follow the same connection scheme for both channels of the input and output wiring to avoid audio phasing problems.
Interfacing with unbalanced sources can sometimes be improved with a pseudo-balanced connection. For a complete tutorial on balanced and unbalanced interfacing to other equipment, please refer to Appendix 1 of this manual.
4.13 Output Connections
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The output impedance of 65 ohms is optimized for driving long cables and consequently a Compellor can drive just about any kind of line, balanced or unbalanced, of any length. Unique servo balanced output circuitry automatically maintains the proper gain and level into a balanced or unbalanced output line.
Output connections are made by means of 3-pin male XLR jacks. The pinout follows the same conventions as the input jacks described above, and you should exercise the same care about wiring as described for input wiring. Refer to Appendix 1 for complete details about wiring and interfacing to other equipment.
4.13 Summary
If you pay attention to the line voltage setting, reference level, and i/o wiring you should have no trouble operating the Compellor. If any difficulties are experienced while installing the Compellor, other information contained in this manual will probably supply adequate assistance. Please study this manual before contacting the factory for assistance.
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