Controls

Bypass

Bypasses the AGC gain stage. The Gain Change Meter continues to operate as though the device were active.

Note: When the bypass is engaged, the AGC continues to compute as the gain changes, and although this computed gain is not applied to the signal passing through the device, the gain change meter continues to function as if bypass were not engaged.

Response Time

Determines how fast the AGC adjusts the gain in response to a change in the side chain signal level.

Threshold Level

The Threshold level and associated logic is intended to detect pauses in speech and suspend operation of the AGC during these pauses. If this feature were not provided, the AGC would eventually turn up a silent input to the Maximum Gain setting.

When the RMS input level falls below the threshold level and Gain Recovery is switched off, the AGC enters a frozen state. In this state, the gain through the device will longer be updated based on the input signal level. With Gain Recovery enabled, the gain applied to the input signal gradually returns to unity at the rate determined by recovery time setting.

Tip: For most applications, the threshold level should be set so that the quietest valid source level is above the point where the AGC would enter the frozen state by at least 6 dB. An input with no source (such as an open microphone channel) being fed into the AGC should cause the AGC to either remain frozen or return to unity.

When properly set, only a true source (not background noise) will cause the AGC to become active (as shown by the Below Threshold Indicator).

State

Indicates the current status of the AGC.

When Recovery is lit, the gain is in the process of returning to unity.

Maximum Gain

This is the maximum level of the gain that the AGC provides. This prohibits the AGC from applying so much gain to a quiet source that problems such as feedback arise.

Note: There is no limit to the amount of attenuation the AGC can produce.

Ratio

Sets the attenuation ratio to be applied to the input signals below the threshold, up to the maximum attenuation. For example, if the input signal is at -20dB, a ratio of two will result in the signal being attenuated to -40dB.

Target level

The desired RMS level of the output signal. The AGC will apply an appropriate gain to the input signal in order to achieve this desired output level.

Hold Time

Determines how long the gate will remain open after the side chain signal falls below the threshold. The hold time evens out the response of the device by allowing some time for the signal to exceed the threshold after amplifying the output signal. If recovery is enabled, the hold time value is replaced by the recovery time value.

Recovery Time

The time taken for the gain to return to unity once the input signal has fallen below the Threshold Level.

Note: Gain recovery must be enabled.

Recov Enb

Enables gain recovery.