Gating Automatic Mic Mixer Component

Absolute Threshold (Legacy)

VIDEO TUTORIAL: Video tutorial available online for Gated Automatic Mixer.

The Gated Automatic Mixer is typically used in applications with multiple microphones, and at times, multiple microphones being used at the same time. The microphones in use can be prioritized using three different modes: Auto, Priority, and Filibuster or combinations of these. The channels open and close based on Threshold levels set for each channel, and optional Side Chain filters, or manual control. Attenuation controls help control feedback based on the number of microphones open at one time.

The Gated Automatic Mixer is capable of up to 512 channels:

Controls

Controls are used during the design phase of a system to establish initial settings, and during normal system operation to make adjustments for different events. The controls can be adjusted only in Emulate or Run mode. Only Run mode actually processes audio. The controls listed below are divided into sections to match the Control Panel sections.

Once you establish the initial settings for a component, you can save those settings, along with all the other component's settings, in a Snapshot.

Input

Control

Function

Default/Range

Open

(indicator)

Indicates if the associated channel is open or closed.

NOTE:  The Depth knob sets the amount of attenuation applied to any input channel when the channel's Gate is closed.

On = open

Off = closed

Manual

(button)

Opens the channel until manually closed.

Off/On

Mode

(drop-down)

You can choose one of three modes for the channel.

Auto Mode opens the channel when the RMS input level exceeds the Threshold.

Priority Mode opens the channel when the RMS input level exceeds the Threshold and the Priority set for the channel is higher than any other Priority channel currently open.

Filibuster Mode opens the channel when the RMS input level exceeds the Threshold no other channels are open.

When the Side Chain is active, these modes are additionally modified by the selected filter.

Auto

Priority

Filibuster

How Modes interact with each other.

 

Is Open First

Exceeds Threshold While Another Channel is Already Open

Auto

Priority

Filibuster

Auto

Open

Open

Open

Priority

Open

Higher Priority - 1st is attenuated, 2nd is opened

Lower Priority - 1st stays open, 2nd is attenuated

Open

Filibuster

Open

Open

1st stays open

2nd is attenuated

Priority

(integer)

Used to set the priority order of the channels. All inputs with the same priority can be open at the same time. This setting has no effect when the channel is not in Priority Mode.

TIP:   Leave gaps in your priority lists so you can easily change the priority of one mic without having to shift other priorities to make room for a single change.

Range 10000 to 1

Highest = 10000

Lowest = 1

Threshold

(dB)

Sets the peak level at which the gate opens and allows audio to pass on this channel.

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 for the Mix output, but does not affect the individual Output Channels.

Default = 0

Range = -100 to 20

Gate

Control

Function

Default/Range

Last Mic On

(button)

Leaves the last microphone that was used in the open condition, until another microphone exceeds the Threshold.

On/Off

ID Gating

When the ID Gating button is on, Q-SYS prevents multiple gates from opening if they are fed by the same source such as a talker who is positioned between two microphones.

Off/On

Background Percentage

(%)

This control provides adaptive threshold functionality.

This feature allows you to set the microphone Threshold levels fairly low for rapid response, but prevents the gates from opening when the background noise level rises.

The background signal is the sum of all the microphone input signals. The Background Percentage knob determines the percentage of background signal used to raise the Threshold levels.

TIP:   Set the Threshold levels when the room is quiet, if the gates open when the room gets noisy, increase the Background Percentage until the gates close.

The following example uses a 5 dB difference between the Threshold level, and the background noise level, and shows the effective Threshold level compared to the Background Percentage knob setting.

Threshold level set at: -30dB

Background signal level from microphones: -25 dB

Effective Threshold Level

Background % Knob

-30 dB

0%

-26.8 dB

25%

-24.5 dB

50%

-22.6 dB

75%

-21.1 dB

100%

Default = 0

Range = 0 to 100

Depth

(dB)

The knob sets the amount of attenuation applied to any input channel when the channel's Gate is closed.

 

Hold Time

(Seconds)

The knob the sets minimum time an input stays open once it is opened, or the length of time an input stays open after the RMS input level drops below the Threshold Level. This is to prevent the gate from opening and closing due to momentary pauses in the input.

Default = 0.10

Range 0 to 1

NOM (Number of Open Mics)

Control

Function

Default/Range

Max NOM

NOM is counted beginning at input 1 and once the maximum NOM has been reached gates will be closed for the remaining inputs. If you want a limited NOM to always contain the highest priority (open) inputs, assign input 1 the highest priority, and assign the rest of the inputs in descending priority order.

Equal to the number of Channels assigned in the Properties.

NOM Attenuation Type

(Dropdown list)

When Logarithmic is selected, the output is attenuated by the amount specified by the Attenuation Step control for each open channel every time NOM is doubled.

Assuming an Attenuation Step of 1 dB

NOM

Attenuation

1

0 dB

2

1 dB

4

2 dB

8

3 dB

When Linear is selected, the output is attenuated by the amount specified by the Attenuation Step control for each open channel every time NOM increases by 1.

Assuming an Attenuation Step of 1 dB:

NOM

Attenuation

1

0 dB

2

1 dB

3

2 dB

4

3 dB

Logarithmic / Linear

Attenuation Step

(dB)

The amount of attenuation added every time another mic opens, excluding the first mic opened.

Default = 3.00

Range = 0 to 20

Max Attenuation

(dB)

Sets the maximum amount of attenuation that can be applied to the output regardless of the NOM.

Default = 20

Range = 0 to 40

Response Time

(seconds)

Adjusts the time constant that determines the time it takes for the attenuation to be applied to the output when there is a change in the NOM.

Default = 0.02

Range = 0.02 to 10

NOM

(display)

The total number of open microphones.

0 to 512

Gain

(dB)

Measures the output gain with respect to the amount of attenuation applied. For example, 40 dB of applied attenuation would result in a -40 dB change in the output gain.

0 to -40

Side Chain

Control

Function

Default/Range

Bypass

(button)

Bypasses any Side Chain filtering effects.

Off/On

Type

(drop-down)

Low-Pass - Allows frequencies below the Frequency setting to pass unattenuated.

High-Pass - Allows frequencies above the Frequency setting to pass unattenuated.

Band-Pass - Allows frequencies within the Bandwidth to pass unattenuated. The Bandwidth is centered on the Frequency setting,

Band-Stop - Allows all frequencies to pass unattenuated except those within the Bandwidth. The Bandwidth is centered on the Frequency setting. Sometimes known as a Notch Filter.

Parametric - Allows control of all three parameters: Bandwidth, Frequency, and Gain.

High-Shelf - Allows you to boost or attenuate signals above the set Frequency. Frequencies below the set Frequency are not affected.

Low-Shelf - Allows you to boost or attenuate signals below the set Frequency. Frequencies above the set Frequency are not affected.

Default = High-Pass

Bandwidth

(octave)

Sets the bandwidth of the filter.

The control is available with the Band-Pass, Band-Stop, Parametric Side Chain filters.

Default = 1.00

Range = 0.01 to 1.00

Frequency

(Hz)

Sets the upper, lower, or center frequency, depending on the filter.

The control is available with all filter types.

Default = 100

Range = 20 to 20 k

Gain

(dBFS)

Controls the gain of the Side Chain signal.

The control is available with the Parametric, Low-Shelf, High-Shelf filters.

Default = 0

Range = -100 to 20

Properties

The properties of a component are used in the Design phase to establish the size and characteristics of the component. They can be changed only in the Design Mode when the component is selected. Select and drag the Gated Automatic Mixer component from the Schematic Library into the Schematic.

Property

Function

Choices

Channels

Sets the number of input and output channels for the Component.

2 to 512

Outputs

All inputs mixed into one output

One output channel per input channel, no mix is provided

Both

Mix Only

Channel Only

Mix and Channel

Side Chain Filter

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 filtered by the Side Chain 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 audio output, only the control of the gate.

No / Yes

Control Pins

The available Control Pins depend on settings in Properties.

Per Channel

Pin Name

Value

String

Position

Pins Available

Manual

0

1

disable

enable

0

1

Input / Output

Mode

0

1

3

Auto

Prior

Filib (Filibuster)

0

.500

1.00

Input / Output

Open

0

1

false

true

0

1

Output

Priority Level

1 to 10000

1 to 10000

0 to 1.00

Input / Output

Threshold

-100 to 20

-100 dB to 20 dB

0.000 to 1.00

Input / Output

General

Pin Name

Value

String

Position

Pins Available

Default Settings

Background Percentage

0.0 to 100

 

0.000 to 1.00

Input / Output

Gate Depth

0 to 20

0 dB to 20 dB

0.000 to 1.00

Input / Output

Hold Time

0.00 to 10

0 ms to 1 s

0.000 to 1.00

Output

ID Gating

0

1

disabled

enabled

0

1

Input / Output

Last Mic On

0

1

disable

enable

0

1

Input / Output

Linear NOM Attenuation

0

1

disable

enable

0

1

Output

Max NOM Attenuation

0 to 20

0 dB to 40 dB

0.000 to 1.00

Input / Output

Maximum NOM

1 - n

1 to n

0.00 to 1.00

Input / 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

NOM

0 to n

0 to n

0 to 1.00

Output

NOM Attenuation Step

0 to 20

0 dB to 40 dB

0.000 to 1.00

Input / Output

NOM Gain

-100 to 20

-100 dB to 20 dB

0.000 to 1.00

Output

NOM Response Time

0.0001 to 1

.100 ms to 1 s

0.000 to 1.00

Input / Output

Available with Side Chain

Bandwidth

.010 to 1.00

.010 to 1.00

0 to 1.00

Input / Output

Bypass

0

1

active

bypass

0

1

Input / Output

Frequency

10 to 20000

10 Hz to 20 kHz

0.000 to 1.00

Input / Output

Gain (Side Chain)

-100 to 20

-100 dB to 20 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

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