Australian Monitor AMISCL2 User Manual

Page 1
AMISCL2
STEREO COMPRESSOR LIMITER
INSTALLATION & OPERATION MANUAL
Page 2
Page 3
INTRODUCTION AND CONTENTS
The Australian Monitor Pro Series AMISCL2 is a 1 RU, dual channel compressor limiter.
Featuring an expander/gate, compression and limiting per channel, the AMISCL2 utilises a high quality VCA to give excellent performance from a budget priced dynamics processor.
With added features like selectable Automatic attack and release times and EQ enhancement which automatically compensates for high end loss when heavy compression is taking place, the AMISCL2 has the features and the performance of a compressor/limiter many times the price.
INTRODUCTION 3
FRONT PANEL 4
REAR PANEL 5
SET UP & OPERATION 6
SPECIFICATIONS 7
AUS, EUR, USA
Copyright 17th Oct 2004
Rev A: 17th Oct 2004
This symbol is intended to alert the user to the presence
of uninsulated “dangerous voltage” within the product’s
enclosure that may be of sufficient magnitude to
constitute a risk of electric shock to persons.
This symbol is intended to alert the user to the presence
of important operation and maintenance (servicing)
instructions in the literature accompanying the appliance.
Caution:
To prevent electric shock do not use this (polarised) plug
with an extension cord, receptacle or other outlet unless
the blades can be fully inserted to prevent blade exposure.
To prevent electric shock, match wide blade of plug to
wide slot, fully insert.
AMISCL2 INSTALLATION & OPERATION MANUAL PAGE 3
Page 4
FRONT PANEL
1 3 14
POWER SWITCH
1
This switches the mains power "on" to the unit.
COMPRESSOR/LIMITER SECTION
2
Refer to inset box immediately opposite.
3
EXPANDER/GATE THRESHOLD
This control adjusts the threshold level of the expander/gate within a range from off (bypass) to +10dB. The Red LED glows when expansion occurs.
ENHANCER
ENHANCEMENT
14
Dynamic enhancement allows you to replenish any high frequencies lost through the compression process, for natural sounding dynamics control. This control allows you to vary the amount of dynamic enhancement added. Enhancement is only added when compression is taking place.
2
4 5 6 78 10 12 13119
COMPRESSOR LIMITER SECTION
THRESHOLD
4
This controls threshold at which compression will start to occur. It has a range from -40 to+20 dBu.
RATIO
5
This control determines the compression ratio between the input and output level for all signals exceeding the threshold point. The ratio can be adjusted from 1:1 (unity gain) to infinity:1 (Limiting)
ATTA CK
6
The attack control determines the speed at which the compressor will respond to sig­nals that exceed the threshold. The attack range is from 0.1 to 200 milliseconds.
RELEASE
7
The Release control determines the amount of time it will take the compressor to return to unity gain after signal falls below the threshold level. This can be adjusted from 0.05 to 4 seconds.
the program material. This function allows for unobtrusive musical compres­sion of signals or mixes with widely varying dynamics.
OUTPUT LEVEL
9
This control allows for an increase or decrease of the output level by up to 20dB, thus allowing the user to compen­sate for any level loss due to the compression or limiting process.
IN/OUT SWITCH
10
This switch allows the compressor/lim­iter section to be bypassed. This makes A/B comparisons between original and processed material very simple.
GAIN REDUCTION METER
11
This 8 segment LED meter shows the actual gain reduction per channel and has a range from 0 to 30dB.
AUTO LED
12
This shows when the “Compressor Auto” function is active.
AUTO IN
8
The Auto In switch disables the Attack and Release controls and controls these parameters automatically from
ACTIVE LED
13
This shows when the compressor/limiter is switched in.
PAGE 4 AMISCL2 INSTALLATION & OPERATION MANUAL
Page 5
16 17 18 19 20
CHANNEL DETAIL
TRS LINE OUT
16
This 6.35mm TRS connector is a bal­anced or unbalanced line level output.
TRS LINE IN
19
This 6.35mm TRS connector accepts a balanced or unbalanced line level input.
REAR PANEL
22 232115
CHANNEL DETAIL
15
Refer to inset box below.
MAINS VOLTAGE SELECTOR
21
This switches mains voltage from 230VAC to 240VAC. Please ensure that this switch is set to the correct voltage for your part of the world.
FUSE HOLDER
22
Please note that the AC voltage selection is defined by the position of the fuse holder. If you intend to change the operating voltage, remove the fuse holder and twist 180 degrees before re inserting it. Matching the two markers monitors the selected voltage.
XLR LINE OUT
17
This XLR connector is a balanced line level output.
XLR LINE IN
18
This XLR connector accepts a balanced line level input.
DETECTOR LOOP INSERT
20
This 6.35mm TRS jack allow for an equalis­er or other processor to be inserted into the signal path. Note that the ring of the insert point is the send and the tip is the receive.
MAINS POWER LEAD
23
This connects to mains AC power. Please ensure that the correct voltage is set for your part of the world. (See 21)
AMISCL2 INSTALLATION & OPERATION MANUAL PAGE 5
Page 6
SET UP AND OPERATION
Fig 1 The interactive relationship between the operating level and the headroom
It is possible to further improve the audio quality by constantly monitoring the programme material with the aid of a volume fader, which manually levels the material. During low passages the gain is increased, during loud passages the gain is reduced. Of course it is fairly obvious that this kind of manual control is rather restrictive; it is difficult to detect signal peaks and it is almost impossible to level them out. Manual control is simply not fast enough to be satisfactory.
The need therefore arises for a fast acting automatic gain control system which will constantly monitor the signals and which will always adjust the gain to maximise the signal-to-noise ratio without incurring signal distortion. This device is called a compressor or limiter.
COMPRESSOR/LIMITERS
By measuring the dynamic range of musical instruments and micro­phones, you will find that extreme amplitudes will occur which will often lead to overload in subsequent signal processing equipment. These signal peaks can lead to heavy distortion. To avoid this kind of distortion or, for example, to avoid loudspeakers being damaged by overload,
The principal function used in these devices is dependent on an automatic gain control as mentioned in the previous section, which reduces the amplitude of loud passages and therefore restricts the original dynamics to a desired range. This application is particularly useful in microphone recording, to compensate for level changes which are caused by varying microphone distances.
Although compressors and limiters perform similar tasks, one essential point makes them different:
A compressor controls the signal “gently” over a wider range. A limiter continuously monitors the signal and intervenes as soon as an adjustable level is exceeded. This level is called the threshold. Any signal exceeding this threshold will be immediately reduced back to the adjusted threshold level.
Compressors
Limiter
abruptly limits the signal above a certain level, while a
or
Limiters
are used.
the threshold, the signal is reduced in level, relative to the amount the signal exceeds this point. This gain reduction is set by the ratio control.
Generally, threshold levels for compressors are set below the normal operating level to allow for the upper dynamics to be musically com­pressed. For limiters, the threshold point is set above the normal oper­ating level ini order to provide reliable signal limiting and thus protect subsequent equipment.
EXPANDERS/NOISEGATES
Audio, in general, is only as good as the source from which it was derived. The dynamic range of signals will often be restricted by noise. Synthesisers, effects devices, guitar pickups, amplifiers etc generally produce a high level of noise, hum or other ambient background hiss, which can disturb the quality of the program material.
Normally these noises are inaudible if the level of the desired signal lies significantly above the level of the noise. This perception by the ear is based on the “masking” effect: noise will be masked and thus becomes inaudible as soon as considerably louder sound signals in the same frequency band are added. Nevertheless, the more the level that the desired signal decreases, the more the noise floor becomes a disturbing factor.
Expanders or noisegates offer a solution for this problem: these devices attenuate signals when their amplitudes drop, thereby fading out the background noise. Reliant on this method, gain controlling amplifiers, like expanders, can extend the dynamic range of a signal and are therefore the opposite of a compressor.
In practice, it is shown that an expansion over the entire dynamic range is not desired. With an expansion ratio of 5:1 and a processed dynamic range of 30dB, an output dynamic range of 150dB will be the result, exceeding all subsequent signal processors, as well as human hearing. Therefore, the amplitude control is restricted to signals whose levels are below a certain threshold. Signals above this threshold pass through the unit unchanged. Due to continuous attenuation of the signals below this threshold, this kind of expansion is termed “downward” expansion.
The noisegate is the simplest form of an expander: in contrast to the expander, which continuously attenuates a signal below the threshold, the noise-gate cuts off the signal abruptly. In most applications this method is not very useful, since the on/off transition is too drastic. The onset of a simple gate function appears very obvious and unnatural. To achieve an inaudible processing of the program material, it is necessary to be able to control the signal’s envelope parameters.
compressor
A has a certain threshold level. However, in contrast to the limiter, signals exceeding the threshold are not reduced abruptly but gradually. Above
also monitors the program material continuously and
PAGE 6 AMISCL2 INSTALLATION & OPERATION MANUAL
Page 7
SPECIFICATIONS
AUDIO INPUT
Type RF-filtered, Servo-balanced input stage
Impedance 60KΩ balanced
Nominal Operating Level -10dBu to +4dBu Maximum Input Level +21dBu balanced and unbalanced CMR @ 1kHz >40dB
DETECTOR INPUT
Type DC de-coupled, unbalanced input
Impedance >20K
Maximum Input Level +21dBu
AUDIO OUTPUT
Type Electronically buffered output stage
Impedance <40
Maximum Input Level +21dBu Bandwidth 5Hz to 50kHz, +0, -1dB THD @ +4dBu 0.05% typ. THD @ +20dBu 0.1% typ. IMD (SMPTE) @ +10dBu 0.01% typ. Noise & Hum, unity gain >93dBu Noise & Hum, fully off >97dBu Crosstalk @ 20kHz >85dBu CMR @ 1kHz >60dBu
COMPRESSOR SECTION
Type IKC (Interactive Knee Control) Compressor Threshold Variable (-40 to +20dBu) Ratio Variable (1:1 to LIM.) Attack Variable (0.1 to 200 msec./20dB) Release Variable (-20 to +20dB)
GATE SECTION
Type IRC (Interactive Ratio Control) Expander/Gate Threshold Variable (Off to +10dBu)
DYNAMIC ENHANCER SECTION
Type Dynamically Controlled Frequency Correction Process Variable (Off to 6)
FUNCTION SWITCHES
In/Out Bypass switch Auto Programme-dependent attack and release times
INDICATORS
CLOSE LED LED indicates onset of the Expander/Gate 8 element GAIN REDUCTION meter 1/2/4/6/10/15/20/30dB
POWER SUPPLY
Mains Voltages 100-120/200-240 VAC 50-60Hz Power Consumption 9 Watts Fuse 320mA (100-120V); 160mA (200-240V) slow-blow Mains Connection Standard IEC receptacle
PHYSICAL
Dimensions H x W x D 13/4” (44.5mm) x 19” (482.6mm) x 8.5” (217mm) Net Weight 3kg Shipping Weight 4.3kg
As a result of these efforts, modifications may be made from time to time to existing products without prior notice. Specifications and appearance may differ from those listed or shown.
AMISCL2 INSTALLATION & OPERATION MANUAL PAGE 7
Page 8
AUSTRALIA AND NEW ZEALAND
www.australianmonitor.com.au
SYDNEY
(NSW & ACT SALES)
149 Beaconsfield Street Silverwater NSW 2128 Private Bag 149 Silverwater NSW 1811 Phone: (02) 9647 1411 Fax: (02) 9648 3698 Email: nsw@audiotelex.com.au
MELBOURNE
(VIC & TAS SALES)
22/277 Middleborough Road Box Hill VIC 3128 PO Box 151 Blackburn South VIC 3130 Phone: (03) 9890 7477 Fax: (03) 9890 7977 Email: vic@audiotelex.com.au
BRISBANE
(QLD SALES)
42 Commercial Road Fortitude Valley QLD 4006 PO Box 871 Fortitude Valley QLD 4006 Phone: (07) 3852 1312 Fax: (07) 3252 1237 Email: qld@audiotelex.com.au
EUROPE/ASIA/MIDDLE EAST
www.australianmonitor.com.au
INTERNATIONAL SALES
149 Beaconsfield Street Silverwater NSW 2128 Australia Private Bag 149 Silverwater NSW 1811 Phone: 61 2 9647 1411 Fax: 61 2 9648 3698 Email: international@audiotelex.com.au
ADELAIDE
(SA & NT SALES)
31 Walsh Street Thebarton SA 5031 PO Box 157 Hindmarsh SA 5007 Phone: (08) 8352 4444 Fax: (08) 8352 4488 Email: sa@audiotelex.com.au
PERTH
(WA SALES)
299 Fitzgerald Street West Perth WA 6005 PO Box 404 North Perth WA 6906 Phone: (08) 9228 4222 Fax: (08) 9228 4233 Email: wa@audiotelex.com.au
USA/SOUTH AMERICA
www.australianmonitor.com
SENNHEISER ELECTRONIC CORPORATION
1 Enterprise Drive Old Lyme CT 06371 USA Phone: 1 860 434 9190 Fax: 1 860 434 1759 Email: jalexander@sennheiserusa.com
AUCKLAND
(NZ SALES)
Unit B, 11 Piermark Drive Albany 1331 New Zealand PO Box 512 Albany 1331 Phone: (09) 415 9426 Fax: (09) 415 9864 Email: audiotlx@nznet.gen.nz
Loading...