DRAWMER DS201 – Dual Noise Gate

The DS201 is a sophisticated dual channel noise gate incorporating a number of features pioneered by Drawmer, which are invaluable to the sound engineer, and not found on conventional noise gates.

• Variable high pass and low pass filters for "frequency conscious" gating.
• Comprehensive envelope control, attack, hold, decay, and range.
• Key input for external triggering.
• “Key Listen" facility.
• Extremely fast attack time, to preserve the natural attack of the sound.
• Balanced inputs and outputs.
• Stereo linkable.
• Can be used for "Gating" or "Ducking“.
• High audio specification.

These features and its "user friendliness" have made it the "industry standard" throughout the world.

Setting up noise gates can be tedious and unrewarding. For example, when attempting to separate a signal from unwanted noise or crosstalk that is relatively high in level, spurious triggering of the gate by unwanted components within the sound can be a serious problem. This can often be experienced in the studio when recording a drum kit. If a gate is used to clean up the snare drum sound it is quite likely that the nearby hi-hats will spill into the snare drum microphone and cause the gate to open. Increasing the threshold level may cure this problem, but then there is a very real danger that any quieter snare drum beats may not cause the gate to open at all and the performance can easily be ruined.

The DRAWMER solution to this problem is the inclusion of two variable filters, one high-pass and one low-pass, which act upon the side-chain keying circuitry. By setting the output switch to key listen the user can hear the action of the filters and adjust them to reject high frequency spillage from the hi-hats. This now enables the gate to only open on the lower frequencies present in the snare drum.

Drawmer pioneered the concept of frequency conscious gating, and the Drawmer DS201 was the first noise gate to include this feature. 

The very fast attack of the DS201 means that it can open in a matter of micro seconds, thus preserving the natural attack of whatever sound is being gated and the comprehensive envelope controls mean that the gain can be changed at whatever rate best suits the material being processed. With vocals for example, a fairly fast attack is needed so as not to clip the leading consonants but a slower release time will prevent the end of words being clipped off and will also fade out any noise gradually rather than cutting it off abruptly. This latter point is very important as the human ear is far more sensitive to rapidly changing noise levels than to a constant low level noise.

Another important role played by the gate is in the reshaping of existing sounds. An example of this might involve a simple sampling delay line used to store a sound to be re-triggered later and added to a mix. A gate can be used to impart a slower attack or faster decay to the sound and careful setting of the decay envelope can effectively hide any noise present at the end of the sample. When using a sampler or drum machine the gate can be considered a triggered envelope shaper, and the wide range allowed by the envelope controls make the DS201 ideal for this application.

The unit can be switched to accept a key input, which allows the gate to be triggered externally. An example of this would be to use a snare drum signal to open the gate on a separate ambient microphone to create a natural alternative to gated reverb.

Each channel can be individually switched from Gating to Ducking for \'voice over\' applications or the removal of \'clicks\' and \'pops\'.

The AD2055 combines 100% discrete, pure class A signal amplifiers with state-of-
the-art passive and active filter topologies. The AD2055's unique circuitry delivers
very high resolution transient detail at the operational extremes of real world equalization
demands. The AD2055 auto-bias DC servo loop control eliminates the need for all
interstage capacitor coupling. The AD2055 breathes life into all musical performances!
 
AD2055 FEATURES
Pure Class A, 100% discrete design
Smooth musical detail and sonic excellence
Minimum audio signal path
Dual mono operation
Transparent active and passive filter design
High headroom +30dB Very low noise -94dB
Fully balanced inputs and outputs
DC coupled, no transformers in audio path
Switched frequencies in high and low bands
Mid bands use X10 frequency for extended range
Wide bandwidth -3dB 1Hz to 450kHz
Low distortion less than 0.5% THD and IMD
All signal routing with sealed silver relays Conductive
plastic potentiometers for low noise
External 150W toroidal power supply 100% discrete
power supplies for audio path
Long lasting, stainless steel hardware
 
SONIC EXCELLENCE
The Avalon AD2055 Pure Class A music equalizer is the most powerful, low noise
parametric equalizer available today. Designed to optimize absolute signal integrity
and musical performance, the AD2055 combines the best of active and passive filter
topologies with sonic excellence unequaled by lesser designs. The AD2055 is the
perfect solution for two buss music-program equalization, special instrument EQ and
FX applications and ultra high performance mastering studio's.

Features include state-of-the-art, balanced 100% discrete, Pure Class A signal amplifiers,
practical user features and rugged hardware designed to deliver true high performance
audio for many years. 

PASSIVE-ACTIVE FILTER DESIGN
Avalon equalizers feature the unique combination of both active and passive filter EQ designs.
This special combination enables the AD2055 to deliver high speed transient detail at the
operational extremes of real-world equalization demands. The passive high and low bands offer
alternate musical tone range to the full function active parametric mid bands. Passive equalizers
have long been a favorite with music lovers around the world.  Full bodied, powerful (up to +/-32dB,
64dB range !) and sweet frequency selections are the benefits of the passive high-low EQ bands.
The full bandwidth twin mid bands provide variable frequency selection (X10 frequency multipliers
for very wide range), variable Q (width) and amplitude control.

MINIMUM SIGNAL PATH DESIGN
Avalon's advanced true symmetry design offers high-voltage, large headroom, extended bandwidth
and very low noise. The use of 100% discrete, Pure Class A signal amplifiers give the serious music
professional unlimited sonic character and a natural harmonic detail that enhances the program
material and becomes one with the music itself. The Avalon AD2055 breathes life!

AD2055 SPECIFICATIONS
Circuit Topology  High-voltage 100% discrete, balanced and symmetrical
Class A 
Output Gain Range  Unity Gain 
Maximum Input Level  +30dB balanced XLR pin 2 hot 
Maximum Output Level  +32dB balanced 600 ohms, DC coupled, high-current
discrete Class A 
Input / Output Type  XLR type, pin 2 hot balanced 
Noise 20kHz Unweighted  -94dB (EQ in) 
Distortion THD, IMD  0.5% (typical 0.05% at +6dB 1kHz) 
Frequency Response -3dB  1Hz to 450kHz (input band limited) 
Equalizer Type  Passive high and low bands plus two fully parametric mid
bands 
Bypass  Hard-wire relay bypass for equalizer in-out 
Low Band F1  Passive, amplitude to -32dB to +32dB shelf or peak-dip curve 
F1 Frequency Range  Switched 10 position 18Hz, 25, 30, 50, 72, 100, 150, 215,
300, 450Hz 
Mid Band F2  Active, amplitude to -16dB to +16dB peak-dip curve 
F2 Frequency Range  Variable 35Hz to 450Hz (x10) 350Hz to 4k5Hz, Q (width)
0.3 to 3.0 
Mid Band F3  Active, amplitude to -16dB to +16dB peak-dip curve 
F3 Frequency Range  Variable 160Hz to 2k0Hz (x10) 1k6Hz to 20kHz, Q (width)
0.3 to 3.0 
High Band F4  Passive, amplitude to -26dB to +26dB shelf or peak-dip curve 
F4 Frequency Range  Switched 10 position 1k5Hz, 2k5, 3k5, 5k, 7k2, 10k, 12k5,
15k, 20k, 25kHz 
AC-DC Power  External AC supply, 150w toroidal transformer, 4 pin cable 90v
isolated, 
(B2T Power Supply Included)  100-240v selectable 50/60Hz, 150w max 
Dimensions  19 x 3.5 x 12 in (482 x 88 x 305mm) 
Shipping weight  30lbs (13.6 kg) 

Features
Enhance switch to restore spectral balance of compressed signal
Switchable Mode - Dual Channel or Stereo linked
Above or Below Threshold LEDs
Balanced XLR and Jack Inputs and Outputs
Intuitive, user friendly layout
Flawless performance

Innovation
The ARX COMPO? is a unique compressor/limiter designed for use in any
professional audio dynamics control application, packaged in a compact 1
RU chassis.The COMPO operates as two independent compressor/limiters,
with 'industry standard' variable Threshold, Ratio and Output gain controls.
A Stereo Link switch on the front panel lets both channels track as a stereo
pair in a Master/Slave configuration.
Enhance Switch
The COMPO features an 'Enhance' switch, which provides frequency restoration
to preserve the spectral balance of the audio signal, compensating for the sagging
Low and High frequency response of compressed program material.
The best way to think of it is as a 'smart' loudness control.
Wide Scale metering
There is comprehensive LED indication of all operating functions and status. Above
or Below Threshold LEDs on each channel give you instant visual confirmation of
compressor activity, as well as easy to read LED Gain Reduction meters.
Balanced Inputs and Outputs
On the rear panel, each channel has true differential Balanced inputs and outputs,
on both XLR and TRS jack connectors. Other features include an Active/Bypass
switch for each channel, and passive RFI filters on the inputs.
Universal AC Power
AC power range is a universal 100 to 120V or 220 to 240V AC, and is connected to
the unit via a removable power lead and standard 3 pin IEC connector, with built-in
fuse and voltage change switch.
ARX Quality
With its smooth compression, intuitive user friendly layout, high density precision
circuitry, and extensive user-variable operating parameters, the ARX COMPO is the
ideal installation 'set and forget' compressor, and is also equally at home in Studio,
Broadcast and Sound Reinforcement environments.

Every day, ARX Audio interface products solve audio problems for thousands of people
around the world.

T E C H N I C A L S P E C I F I C A T I O N S
Input Impedance Balanced 20 Kohms, Unbalanced 10 Kohms
Input Headroom + 22 dB
CMRR >60 dB, 20 Hz-20 KHz
Output Impedance Balanced 300 ohms, Unbalanced 150 ohms
Output Level (Max) + 22 dB
Frequency Response 20Hz to 20KHz ±0.4dB
Signal to Noise ratio -85 dB Unweighted, -99 dB 'A' weighted
Distortion .02% THD @ 0dB,1KHz
Dynamic Range 107 dB
Enhance Section
Low Enhance 50 Hz, High Enhance 10 KHz
Power Requirements 100/120 V AC, 220/240 V AC
Weight 5 lbs/2.2 Kg
Dimensions 19“W x 1?“H x 6“D, 482 x 44 x 155mm
Input/OutputConnector type XLR, Balanced Jack

Front Panel Controls
Channel A Active/Bypassed IN/OUT switch
Threshold, Ratio and Output Gain controls
Numbered marker panel for labelling compressor assigns
5 segment LED Gain Reduction display
Above/Below Threshold status LEDs
Enhance switch and status LED
Stereo link switch and status LED
Channel B controls identical to Channel A
Rear Panel Connectors
Balanced XLR Input and Output connectors.
Balanced TRS jack Input and Output connectors.
AC input connector, with voltage switch and fuse.
 

Shure DP11EQE Dynamics Processor Specification:

    GENERAL:
        Frequency Response: 20 to 20k Hz +/- 1.0 dB re 1 kHz
        Dynamic Range: 104 dB minimum, A-weighted, 20 Hz to 20 kHz
        Sampling Rate: 48 kHz
        Digital-to-Analog, Analog-to-Digital Conversion: 20 bit resolution
    Voltage Gain:
        1 dB +/- 1dB (power off)
        12 dB +/- 2 dB (input 10 dBV, output +4 dBu)
        12 dB +/- 2 dB (input +4 dBu, output 10 dBv)
        0 dB +/- 2 dB (equal input and output sensitivities)
    Impedance:
        Input: 47 kilohms +/- 20% actual
        Output: 120 ohms +/- 20% actual
    Input Clipping Level
        +18 dBu minimum (at +4 dBu setting)
        +6 dBV minimum (at 10 dBV setting)
    Output Clipping Level
        +18 dBu minimum (at +4 dBu setting)
        +6 dBV minimum (at 10 dBV setting)
    Total Harmonic Distortion
            LED Signal Indicators
        Signal: 40 dB
        Clip: 6 dB down from input clipping
    Propagation Delay from Input to Ouput
        0.8 ms (all filters flat, no dynamics processing, 0 ms delay), up to 2.1 ms (all processing enabled)
    Polarity
        Input to output: inverting optional (default: non-inverting)
        XLR: pin 2 positive with respect to pin 3
        1/4-inch TRS: tip positive with respect to ring
    Operating Voltage
        DP11EQ: 120 Vac, 50/60 Hz, 50 mA max
        DP11EQE: 230 Vac, 50/60 Hz, 25 mA max
        DP11EQJ: 100 Vac, 50/60 Hz, 50 mA max
    Temperature Range
        Operating: 0 degrees to 60 degrees C (32 degrees to 140 degrees F)
    Fuse
        DP11EQ: 120 Vac. Fuse: 100 mA, 250V time delay
        DP11EQE: 230 Vac. Fuse: 50 mA, 250 V time delay
        DP11EQJ: 100 Vac. Fuse: 100 mA, 250 V time delay
    Dimensions
        219 mm x 137 mm x 44 mm (8-5/8 in x 5-3/8 in x 1-3/4 in)
        Weight: 930 g (2.05 lbs)
    DYNAMICS PROCESSOR
        Gate and Expander:
        Threshold: 72 to 1 dB, 0.5 dB resolution
        Attack: 1.0 to 200 ms
        Decay: 0.05 to 1 second
        Gate Hold Time: 0 to 0.5 seconds
    AGC Leveler
        Threshold: 72 to 1 dB, 0.5 dB resolution
        Attack: 0.2 to 3 seconds
        Decay: 0.5 to 5 seconds
        Hinge: Threshold to 1 dB, 0.5 dB resolution
    Compressor and Limiter
        Threshold: 72 to 1 dB, 0.5 dB resolution
        Attack: 1.0 to 200 ms
        Decay: 0.05 to 1 second
        Knee: Hard or Soft selectable
    No Overshoot Peak Limiter
        Propagation delay: 1 ms
        Threshold: 72 to 1 dB, 0.5 dB resolution
        Attack: 0 msDecay: 100 ms
    PARAMETRIC EQUALIZER
        Parametric Filter Frequency Bands
        Up to 9 bands, variable frequency, variable Q
    Boost/Cut Range
        +6 dB to 18 dB per band
        Q Range
        1/40-octave to 2 octave
    High and Low Shelf/Cut Filters
        Shelf, +6 to 18 dB per filter
        Cut, 12 dB per octave nominal
    DELAY
        Up to 1.3 seconds, 21 microsecond resolution

The DPR-504 is a 4-channel noise gate.

Each channel features:
A parametric key filter with key filter listening.
Simultaneous key level and threshold metering with average and
peak metering.
A gate status LED.
A RELEASE/HOLD control (hold tracks proportionally with release
times).
Attack switchable auto/fast (auto tracks signal dynamics for optimum
setting).
Link (links two channels together).
Key source allows external triggers.

The Range switch selects between 7OdB and 2OdB gating depth to
provide alternative release profiles.
The unit features electronically balanced inputs and outputs. 

In today's recording and sound reinforcement environments, the need for multiple channels of high quality, easy to use compression is growing rapidly. The new dbx® 1046 is designed to provide the audio professional with just that: 4 channels of great sounding dbx compression for a variety of applications. Incorporating the industry standard dbx designs and the latest available manufacturing techniques, the dbx 1046 provides pristine sonic quality with that classic dbx sound.

The 1046 provides 4 channels of smooth classic dbx OverEasy® or Hard Knee compression that are perfectly suited for use on individual tracks of your multitrack recorder, and in virtually all applications the separate channels can be individually interfaced and used for entirely independent purposes. Additionally the newly developed PeakStopPlus™ is ideal for protecting your system from the oppressive peaks that can take out valuable drivers in your sound reinforcement rig or studio monitors.

All four channels have the following controls:

Threshold - allows you to set the level at which the compressor starts affecting the gain

OverEasy - allows you to select between soft compression for overall gain control or Hard Knee compression based on the characteristics of the original dbx 160.

Ratio - allows you to set the slope of gain reduction affecting the signal over the threshold level.

Input/Output Meter - allows you to set the meter to check the input and output levels for maximum signal-to-noise ratio and best level matching.

Output Gain - allows you to add make-up gain or to adjust the output level for that channel to match the next device's input gain.

Bypass - hard wire bypass allows you to hear how the compressor is affecting your signal.

PeakStopPlus - allows you to set the maximum signal level you want to pass through this channel. While it's virtually impossible to eliminate distortion, the PeakStopPlus circuit does it gracefully and effectively with minimal distortion.

Stereo Link - allows you to link channels 1&2 and 3&4 for two channels of true stereo compression.

All four channels feature balanced gold plated XLR and 1/4" inputs and outputs, and switchable +4dBu or -10dBV operating level to interface each individual channel with any other device.

So whether you need to control the level, placement in the mix, or overall characteristics of 4 independent signals or control the gain leveling on a couple of stereo pairs, the dbx 1046 is for you.

• Four independent channels of operation, stereo linkable in two pairs
• PeakStopPlus™ limiting control for setting maximum allowable level regardless of compressor settings
• Independent Threshold and ratio controls
• Switchable OverEasy® or Hard Knee compression
• Classic dbx® compression
• Differentially balanced gold-plated XLR and 1/4" inputs and outputs
• True RMS level detection
• Precision metering of input level, output level, and gain reduction
• Dual True stereo or quad mono operation
• Switchable +4dBu or -10dBV operation per channel