Gain-Sharing Automatic Mic Mixer

The Gain-Sharing Automatic Mic Mixer takes a number of audio inputs, allows one or more of the inputs to pass, while attenuating others based on the level and, if Side Chain filters are used, frequency of the input.

The Gain-Sharing Automatic Mic Mixer is primarily used for multiple live microphones operating in the same room together as a system, for example, in boardrooms, classrooms, churches, courtrooms, etc. The Gain-Sharing Automatic Mic Mixer controls the live microphones by turning up microphones when someone is talking and turning down microphones that are not used. It is a voice-activated, real-time process without an operator. The Gain-Sharing Automatic Mic Mixer controls the additive effect of multiple microphones being on at the same time and adapts to changing background noise conditions. The gain of each microphone input is calculated as the ratio of its RMS level to the combined RMS levels of all inputs. This ensures unity system gain at all times.

The Gain-Sharing Automatic Mic Mixer is capable of up to 512 input channels, channel only output, a mixed output, or both, seven Side Chain Filters, and three pre-set Detector Times and one adjustable.

Controls

Input

Control	Function	Default / Range
Open (indicator)	Indicates if the associated channel is open or not.	On = open Off = closed
Applied Gain (dB)	Measures the attenuation applied to a particular Input channel. The gain is either zero or a negative value.	0 to -40
Priority Gain (dB)	Adjusts the gain or attenuation applied to a particular Input channel. For example, you can boost the gain of a mic being used by a soft spoken person and attenuate the gain of a louder person so they can be heard equally in the room.	Default = 0 Range = -100 to 20

Control

Function

Default / Range

Open

(indicator)

Indicates if the associated channel is open or not.

On = open

Off = closed

Applied Gain

(dB)

Measures the attenuation applied to a particular Input channel. The gain is either zero or a negative value.

0 to -40

Priority Gain

(dB)

Adjusts the gain or attenuation applied to a particular Input channel. For example, you can boost the gain of a mic being used by a soft spoken person and attenuate the gain of a louder person so they can be heard equally in the room.

Default = 0

Range = -100 to 20

Mix

Control	Function	Default / Range
Mute (button)	Mutes the Mix channel output. This mutes all Input channels for the Mix output but does not affect the individual Output Channels.	Off / On
Gain (dB)	Adjusts the Mix output channel gain. This applies to all Input channels on the Mix output, but does not affect the individual output channels.	Default = 0 Range = -100 to 10

Control

Function

Default / Range

Mute

(button)

Mutes the Mix channel output. This mutes all Input channels for the Mix output but does not affect the individual Output Channels.

Off / On

Gain

(dB)

Adjusts the Mix output channel gain. This applies to all Input channels on the Mix output, but does not affect the individual output channels.

Default = 0

Range = -100 to 10

Setup

Control	Function	Default / Range
Open Indicator Threshold (dB)	Sets the Applied Gain amount above which the Open indicator shows that the Input channel is open.	Default = -40 Range = -40 to 0
Depth (dB)	Sets the minimum amount of Applied Gain applied to the Input channels.	Default = -40 Range = -40 to 0
Rest Gain (dB)	Sets the amount of Applied Gain for all Input channels when none are open. When one or more channels are open, Applied Gain is being distributed towards the open channels, away from the closed channels.	Default = -30 Range = -40 to 0
Threshold Level (dBFS)	Sets the Input RMS level at which the Applied Gain begins to move away from the Rest Gain. Use this setting to control background noise (such as side conversations) when a mic is not in use.	Default = -40 Range = -80 to 0
Attack Time (s)	Determines how quickly Applied Gain moves towards 0 dB (unity gain) once the Input level exceeds the Threshold Level.	Default = 0.02 Range = 0.02 to 0.100
Hold Time (s)	Sets the minimum time an Input channel stays open once it is opened, or the length of time an Input channel stays open after the Input RMS level drops below the Threshold Level. Use this control to prevent the gate from opening and closing due to momentary pauses in the input.	Default = 0.1 Range = 0.01 to 10.0
Release Time (s)	Determines how quickly Applied Gain moves away from 0 dB once the Input level drops below the Threshold Level and the Hold Time has expired.	Default = 0.1 Range = 0.02 to 10
Detector Time (s)	If enabled in Properties, this control determines the rate of change of the Input RMS detector output in response to changes in the Input signal. Use this adjustment to prevent abrupt changes in the input signal from causing unwanted, momentary output.	Default = 0.1 Range = 0.0001 to 0.1

Control

Function

Default / Range

Open Indicator Threshold

(dB)

Sets the Applied Gain amount above which the Open indicator shows that the Input channel is open.

Default = -40

Range = -40 to 0

Depth

(dB)

Sets the minimum amount of Applied Gain applied to the Input channels.

Default = -40

Range = -40 to 0

Rest Gain

(dB)

Sets the amount of Applied Gain for all Input channels when none are open. When one or more channels are open, Applied Gain is being distributed towards the open channels, away from the closed channels.

Default = -30

Range = -40 to 0

Threshold Level

(dBFS)

Sets the Input RMS level at which the Applied Gain begins to move away from the Rest Gain. Use this setting to control background noise (such as side conversations) when a mic is not in use.

Default = -40

Range = -80 to 0

Attack Time

(s)

Determines how quickly Applied Gain moves towards 0 dB (unity gain) once the Input level exceeds the Threshold Level.

Default = 0.02

Range = 0.02 to 0.100

Hold Time

(s)

Sets the minimum time an Input channel stays open once it is opened, or the length of time an Input channel stays open after the Input RMS level drops below the Threshold Level. Use this control to prevent the gate from opening and closing due to momentary pauses in the input.

Default = 0.1

Range = 0.01 to 10.0

Release Time

(s)

Determines how quickly Applied Gain moves away from 0 dB once the Input level drops below the Threshold Level and the Hold Time has expired.

Default = 0.1

Range = 0.02 to 10

Detector Time

(s)

If enabled in Properties, this control determines the rate of change of the Input RMS detector output in response to changes in the Input signal. Use this adjustment to prevent abrupt changes in the input signal from causing unwanted, momentary output.

Default = 0.1

Range = 0.0001 to 0.1

Side Chain

Control	Function	Default / Range
Bypass (button)	Bypasses the Side Chain controls	Off / On
Type (drop-down list)	Selects the Side Chain filter Type.	Low-Pass High-Pass Band-Pass Band-Stop (Notch) Parametric Low-Shelf High-Shelf
Bandwidth (octave)	Sets the bandwidth of the Band-Pass, Band-Stop, and Parametric Side Chain filters.	Default = 1 Range = 0.01 to 1
Frequency (Hz)	Sets the frequency parameter for all of the Side Chain filters.	Default = 100 Range = 20 to 20000
Gain (dB)	Sets the gain parameter for the Parametric, Low-Shelf and High-Shelf filters.	Default = 0 Range = -100 to 20

Properties

Property	Function	Choices
Channels	Determines the number of audio channels available.	2 to 512
Outputs	Determines the type of output available. Mix Only gives a mix of all channels Channel only gives individual channel outputs Mix and Channel gives a combination	Mix Only Channel Only Mix and Channel (default)
Side Chain Filter	Selecting Yes allows you to select various types of Side Chain filters in the Control Panel. When you select Side Chain, the signal that controls the gate is modified by the filter settings. When Side Chain is not selected, the actual input signals are used to control the gates. The Side Chain filters do not affect the actual audio output, only the control of the gate.	No / Yes
Detector Time	Sets one of three fixed Detector Times, or makes a variable control available in the Control Panel. All of these affect all of the channels.	Use Control 5ms 10ms 20ms 50ms

Control Pins

The available Control Pins depend on settings in Properties.

Pin Name	Value	String	Position	Pins Available
Attack Time	.020 to .100	20.0 ms to 100 ms	0 to 1.00	Input / Output
Bandwidth	.010 to 1.00	.010 to 1.00	0 to 1.00	Input / Output
Bypass	0 1	active bypass	0 1	Input / Output
Depth	-40 to 0	-40 dB to 0 dB	0.000 to 1.00	Input / Output
Detector Time	0.0001 to 100	.100 ms to 100 ms	0.000 to 1.00	Input / Output
Frequency	10 to 20000	10 Hz to 20 kHz	0.000 to 1.00	Input / Output
Gain	-100 to 20	-100 dB to 20 dB	0.000 to 1.00	Input / Output
Gain (Priority Gain)	-100 to 20	-100 dB to 20 dB	0.000 to 1.00	Output
Hold Time	0.010 to 10	10.0 ms to 10 s	0.000 to 1.00	Input / Output
Meter (Applied Gain)	-100 to 20	-100 dB to 20 dB	0.000 to 1.00	Output
Mix Gain	-100 to 20	-100 dB to 20 dB	0.000 to 1.00	Input / Output
Mix Mute	0 1	unmute mute	0 1	Input / Output
Open	0 1	false true	0 1	Input / Output
Open Threshold	-40 to 0	-40 dB to 0 dB	0.000 to 1.00	Input / Output
Release Time	0.010 to 10	10.0 ms to 10 s	0.000 to 1.00	Input / Output
Rest Gain	-40 to 0	-40 dB to 0 dB	0.000 to 1.00	Input / Output
Threshold Level	-80 to 0	-80 dB to 0 dB	0.000 to 1.00	Input / Output
Type	1.00 2.00 3.00 4.00 5.00 6.00 7.00	Low-Pass High-Pass Band-Pass Band-stop Parametric Low-Shelf High-Shelf	0 .167 .333 .500 .667 .833 1.00	Input / Output