ART MDC-2001 Stereo Master Dynamics Controller User's Guide

Introduction

Congratulations on purchasing the ART MDC-2001, considered by many professionals to be the finest, most technically advanced dynamics processor. This manual is provided to help you familiarize yourself with its functions and capabilities.

Features

• Full stereo processing
• Advanced VCA circuitry
• Low noise design
• Separate output gain for each channel
• 100 ohm balanced outputs (XLR and 1/4")
• Switchable detector loop
• Separate Gate Key Input
• Limiter Link for ganging together more than one MDC-2001
• Switchable Input/Output metering

Installation

The MDC-2001 is designed for professional use in a single rack space (1U) all-steel case. For touring applications, ensure the unit's rear is supported to prevent damage from mechanical shock. Avoid placing the unit near heat sources like power amplifiers or tube equipment.

The MDC-2001 does not have a power switch. It is designed to be used with a switched master AC mains power strip. An audio mute circuit engages and disengages the outputs approximately two to six seconds after power is applied or removed.

Connections

All audio connections are made at the rear of the unit via professional 1/4" phone jacks and XLR connectors.

Input

The audio inputs are active balanced type, accepting 1/4" stereo (TRS) jacks or standard XLR connectors. The device can be used in an unbalanced configuration without harm. Input impedance is 20K ohms balanced and 10K ohms unbalanced. Maximum input level is +20dBm.

1/4" Connector Polarity: Tip (+), Ring (-), Sleeve (ground).

XLR Connector Polarity: Pin 1 (ground), Pin 2 (+), Pin 3 (-).

Output

The audio outputs are active balanced type, accepting 1/4" stereo (TRS) jacks or standard XLR connectors. The device can be used in an unbalanced configuration. Output impedance is 100 ohms balanced and 47 ohms unbalanced. Maximum output level is +24dBm.

1/4" Connector Polarity: Tip (+), Ring (-), Sleeve (ground).

XLR Connector Polarity: Pin 1 (ground), Pin 2 (+), Pin 3 (-).

Detector Loop

Use: The detector loop is used for applications like outboard de-essing and ducking.

Operation: When no connection is made, the loop is closed between the detector input and output jacks. Connect external equipment to these jacks. The Detector Loop switch on the front panel must be engaged for the loop to function. When the switch is out, the detector loop output signal is fed to the detector circuit.

Loop input impedance is 1K ohm; loop output impedance is 100 ohms. Tip connections are for the left detector, ring for the right detector, and sleeve for ground.

Gate Key Input

This input is an external link to the Gate detector circuit. A stereo jack connects to each detector output. The tip and ring are connected to the left and right detector inputs, respectively. When no connection is made, the inputs are automatically connected to the detector outputs via the jack's switching capabilities. This input can be used to trigger the gate from an external source, such as a line-level audio signal.

Input impedance is 1K ohm.

Limiter Link

The Limiter Link input allows multiple MDC units to be connected. A "Y" cord is needed for linking three or more units. The limiter sections are linked, and the limiter LEDs indicate which unit is causing the limiting action (the brightest LED indicates the primary unit). Input impedance is 1K ohm.

This input is a direct link to the VCA. The control voltage from this jack has priority. The maximum VCA gain is set by the compressor threshold and slope. There is a 0.5-volt drop between the jack and the VCA.

LED Indicators

• Gain Control Meter: 21 LEDs indicating a range from -30dB to +30dB, showing VCA activity. The center LED indicates unity gain. LEDs to the right indicate increased gain; LEDs to the left indicate decreased gain. This display is always active, allowing adjustments while the unit is bypassed.
• Input/Output Meter: Switchable meter with 8 LEDs per channel, indicating levels from -30dB to +15dB. A yellow LED above the meter select switch indicates input level, while a red LED indicates output level.
• Threshold Indicators: Yellow LEDs indicate when the set threshold of an effect (Compressor, De-Esser, Expander, Noise Gate, Exciter, Peak Limiter) is reached. The Compressor LED lights even with no compression action.
• Peak Indicators: Left and right LEDs light when the audio signal level reaches the peak limiter setting. The brighter LED indicates the channel driving the detector circuit.
• Bypass Indicator: A red LED above the Bypass switch lights when the MDC-2001 is bypassed. The unit is in active mode when the LED is not lit.

Bypass Switch

The Bypass switch on the front panel toggles between bypass and active modes. Bypass mode provides a hard bypass, directly connecting the input and output jacks.

Processor Sections

The MDC-2001 contains six user-controllable processing devices: Compressor, De-Esser, Expander, Noise Gate, Exciter, and Peak Limiter/Clipper. Each section becomes active when its relevant controls are set above their minimum values.

Compressor

Use: Controls dynamic range by reducing gain when the input signal level exceeds a set threshold.

Controls: Input (from -40dB to +10dB), Ratio (1:1 to 40:1), Attack (0.5ms to 50ms), Release (0.1sec to 1.0 sec).

Operation: The Input control sets sensitivity. The Ratio control sets the compression slope. Attack time determines the response to signal increases, affecting dynamics and transients. Release time determines how quickly the unit returns to normal gain after a signal drop. Both Attack and Release controls feature an "Auto Adjust" function that fine-tunes them based on the audio signal.

How It Works: A Voltage Controlled Amplifier (VCA) adjusts gain based on a DC control voltage derived from a detector circuit that monitors the signal level.

De-Esser

Use: Removes sibilance, particularly when using heavy compression.

Controls: Level (0dB to 15dB).

Operation: The Level control adjusts the amount of signal used to control the detector circuit. The De-Esser requires the Compressor section to be active. It processes the signal through a band-pass filter, then a log converter, which drives the VCA to suppress specific frequencies.

Expander

Use: Reduces noise by making quiet passages quieter, effectively increasing dynamic range. It is often used in conjunction with the compressor.

Controls: Threshold (from -50dBm to +20dBm), Slope (1:1 to 1:5).

Operation: The Threshold control sets the level at which the expander begins attenuating the signal. The Expander LED lights when it is active. The Slope control determines the amount of gain reduction. When the signal level falls below the threshold, the gain decreases.

Noise Gate

Use: Eliminates unwanted residual noise or low signal levels below a minimum threshold.

Controls: Threshold (from -90dBm to +20dBm), Hold Time (15ms to 2sec).

Operation: The Threshold control sets the level at which the gate activates when the input signal drops below it. The Noise Gate LED lights when active. The Hold Time control manages how long the gate remains open after the signal drops below the threshold, and also influences the gate's attack time.

How It Works: When the signal level falls below the threshold, a voltage is sent to the VCA, which closes the gate. The Hold Time control manages the gate's open duration and attack.

Exciter

Use: Adds clarity, life, or emphasizes specific frequencies.

Controls: Level (0 to 10), Frequency (4KHz to 15KHz).

Operation: Adjust the Level and Frequency controls to enhance desired frequencies. The LED indicates activity; a dimly lit LED during enhancement and pulsing brightly on occasion is ideal. A brightly lit LED may indicate distortion.

How It Works: The exciter is an upward expander that detects and boosts high frequencies. A high-pass filter allows mid and upper frequencies to be excited.

Peak Limiter/Clipper

Use: Sets a maximum desired level to prevent exceeding it during processing.

Controls: Threshold (0dBm to +20dBm).

Operation: Set the Threshold to the desired maximum level. The Peak LEDs light when the signal reaches the set limit. The clipping circuit engages at 6dB above the set limit level. Attack time is 100-300 microseconds (us), clamping faster transients. The detector monitors the output of the exciter and VCA.

Master Output

Use: Sets the final output level of the MDC-2001.

Controls: Left Channel (from -infinity to +6dB), Right Channel (from -infinity to +6dB).

Operation: Adjust the Left and Right Channel controls to set the final output level of the processed signal, from zero output to a maximum of +6dB gain.

Specifications

• Frequency Response: 16Hz to 28KHz, (+)0, (-).5dB
• S/N Ratio: (-)110dB
• Dynamic Range: 120dB
• T.H.D.: (≤) 0.04% @1KHz
• Maximum Input Level: +20dBm
• Input Impedance: 20K ohm active balanced
• Maximum Output: +24dBm
• Output Impedance: 100 ohm active balanced
• Mechanical: 1.75" H x 19" W x 9.5" D
• Weight: 11.0 Lbs
• Power: 100-125 Volts AC, 60Hz, Internal fuse, 15W typical
• Compressor Threshold: -40dB to +10dB
• Compressor Ratio: 1:1 to 40:1
• Compressor Attack: 0.5ms to 50ms
• Compressor Release: 0.1sec to 1.0sec
• De-Esser Level: 0dB to 15dB
• Expander Threshold: -50dBm to +20dBm
• Expander Slope: 1:1 to 1:5
• Noise Gate Threshold: -90dBm to +20dBm
• Noise Gate Hold Time: 15ms to 2.0sec
• Exciter Level: 0 to 10
• Exciter Frequency: 4KHz to 15KHz
• Peak Limiter Clipper Threshold: 0dBm to +20dBm
• Peak Limiter Clipper Attack Time: 300uS maximum
• Master Output Level: (-)Infinity to +6dB
• Detector Loop Maximum Input Level: +20dBm
• Detector Loop Input Impedance: 20K ohm
• Detector Loop Maximum Output Level: +21dBm
• Detector Loop Output Impedance: 100 ohms
• Gate Key Input Maximum Input Level: +20dBm
• Gate Key Input Impedance: 1K ohm

Manufacturer: Applied Research & Technology, Inc., 215 Tremont Street, Rochester, New York 14608 USA. Telephone: (716) 436 2720. Fax: (716) 436 3942.

Applied Research & Technology, Inc. retains a policy of constant product improvement. Specifications are subject to change without notice. Designed and Manufactured in the United States of America. Model Number: 520-5004-100.

Applications

Ducking/Voice-Over

To reduce the level of specific instruments when a lead vocal needs to dominate, use the Detector Loop. For example, connect audio tracks to be reduced to the MDC-2001 inputs. Patch the lead vocal into the Detector Loop Input. Set the Compressor input control to establish the threshold and the ratio to 40:1. When the vocal exceeds the threshold by 6dB, the other tracks will be reduced by 6dB. This is useful for live DJ situations where the mix needs to be lowered for spoken announcements.

Use of an Outboard Equalizer Applying Equalization to the Noise Gate

An outboard equalizer can limit the bandwidth of a signal to improve Gate performance. Set the equalizer to a specific frequency range to trigger the gate.

Hook-Up: Patch the equalizer between the Detector Loop Output and the Gate Key Input using stereo cables. Connect the equalizer's input to the detector loop output (tip for left, ring for right) and the equalizer's output to the gate key input (tip for left, ring for right).

Set-Up: After connections, set the EQ curve to eliminate unwanted frequencies. Using significant frequencies to trigger the gate makes it close quicker and less susceptible to interference.

Kick Drum

Roll off high frequencies that may bleed from other drums and cymbals. Boost frequencies that correspond with the attack and resonance of the kick drum.

Vocal

Roll off lower and upper harmonic frequencies. Most vocals fall between 300 Hz and 3.5 KHz. Intelligibility of speech centers around 1.8 to 2.5 KHz.

External De-Essing

An outboard equalizer can reduce sibilance in a vocal track. Set the equalizer to decrease the level of "s" sounds when using large amounts of compression.

Hook-Up: Patch the equalizer into the Detector Loop using stereo cables. Connect the equalizer's input to the detector loop output (tip for left, ring for right) and the equalizer's output to the detector input (tip for left, ring for right).

Set-Up: Boost frequencies between 2KHz and 8KHz. Boosting levels in the detector loop decreases the compression threshold, causing sibilance sounds to be attenuated more than the remaining program material.

Appendix A: Diagrams and Definitions

Graphs

• Figure 1: MDC-2001 Compressor IN vs. OUT @ VARIOUS THRESHOLDS. Graph showing output level (dBm) versus input level (dBm) for the MDC-2001 Compressor. It illustrates input/output curves for various threshold settings (-40dB, -30dB, -15dB, -10dB, 0dB) with a constant 40:1 ratio.
• Figure 2: MDC-2001 Compressor VARIOUS SLOPES @ SAME THRESHOLD. Graph showing output level (dBm) versus input level (dBm) for the MDC-2001 Compressor. It illustrates input/output curves for various slope ratios (2:1, 4:1, 10:1, MAX) at a constant threshold.
• Figure 3: MDC-2001 COMPRESSOR/LIMITER CURVES. Graph showing output level (dBm) versus input level (dBm) for the MDC-2001 Compressor and Limiter. It displays curves for Compressor and Limiter at +10dB and 0dB thresholds.
• Figure 4: MDC-2001 EXPANDER VARIOUS SLOPES @ SAME THRESHOLD. Graph showing output level (dBm) versus input level (dBm) for the MDC-2001 Expander. It illustrates input/output curves for various slope ratios (1:1, 1:1.5, 1:2, 1:3, 1:5) at the same threshold.

Circuit Block Diagram

Figure 5: MDC Block Diagram (Each Channel). This diagram illustrates the signal flow from INPUT through various processing stages (DETECTOR, COMPRESSOR, DE-ESSER, EXPANDER, GATE, EXCITER, LIMITER) controlled by parameters like THRESHOLD, SLOPE, ATTACK, RELEASE, HOLD TIME, LEVEL, and FREQUENCY, ultimately leading to the OUTPUT. It also shows connections for DETECTOR LOOP, GATE KEY INPUT, LIMITER LINK, BYPASS SWITCH, OUTPUT GAIN, and METERING.

Panels

Figure 6: Front Panel. Depicts the front panel controls, including sections for COMPRESSOR, DE-ESSER, EXPANDER, NOISE GATE, EXCITER, PEAK LIMITER/CLIPPER, and MASTER OUTPUT. It also shows input/output metering LEDs, a METER SELECT switch, and branding.

Figure 7: Rear Panel. Shows the rear panel connectors, including audio INPUTs (1/4" and XLR), OUTPUTs (1/4" and XLR), DETECTOR LOOP (INPUT/OUTPUT), GATE KEY INPUT, LIMITER LINK, and power input.

Definition of Terms

• Attack Time: The time it takes a compressor, limiter, or expander to react to changes in signal level.
• Compressor: A device that decreases its gain when the input signal level increases, thereby reducing the dynamic range of the program material.
• De-Esser: A device used to eliminate sibilance from heavily compressed program material.
• Detector: A type of circuit which converts an audio signal into a DC control voltage.
• Exciter: A device used to bring out certain frequencies in program material.
• Expander: A device used to make louder passages louder and quieter passages quieter, therefore increasing the dynamic range of the program material.
• Hold Time: The amount of time the noise gate is held open after the signal passes threshold.
• Noise Gate: A device that turns off an audio signal when its level falls below a threshold level.
• Peak Limiter: A device used to prevent instantaneous signal levels from exceeding a set level.
• Release Time: The time it takes a compressor, limiter, or expander to recover from changes in signal level.
• Slope: The rate of attenuation in a compressor or expander.
• Threshold: The level where a compressor, limiter, expander, or noise gate starts to act on the signal.
• VCA: A type of audio amplifier whose gain or attenuation is controlled by an external DC voltage.

Warranty & Service Information

Warranty service for this unit will be provided by Applied Research & Technology, Inc. (ART) for one year from the date of purchase. ART will repair or replace defective products or components at no charge, provided proof of purchase is included. The warranty excludes misuse, abuse, or unauthorized alterations.

Exclusions: Warranty is void if the serial number is altered, defaced, or removed. ART is not liable for consequential damages. Rights may vary by state.

For units purchased outside the United States, service is provided by an authorized ART distributor.

Service Procedure:

1. Verify the unit is the cause of the problem and that all cables are connected correctly and functional.
2. If the unit is at fault, document the problem, including how and when it occurs.
3. Call the factory to obtain a Return Authorization (RA) number.
4. Pack the unit securely in its original carton or a suitable substitute, placed inside another shipping box. Print the RA number clearly under the address. Note: Improper packaging can damage the front panel.
5. Include with the unit: a return shipping address (no P.O. boxes), a copy of the purchase receipt, a daytime phone number, and a description of the problem.
6. Ship the unit to: APPLIED RESEARCH & TECHNOLOGY, INC., 215 TREMONT STREET, ROCHESTER, NY 14608, ATTN: REPAIR DEPARTMENT. Include the RA #.
7. Contact customer service at (716) 436-2720 for RA numbers or repair questions.

ART's policy is constant product improvement; specifications are subject to change without notice. Designed and Manufactured in the USA.