Technical data

DOC-01-TELAS-CRG-4 ASTi ACE Studio Components Reference Guide Rev.M
106 Copyright © 2014 Advanced Simulation Technology inc.
6.3. Expander
Summary: The Expander component is used to reduce the volume of background
noise between speech.
Description: The Expander expands (increases) the dynamic range of a signal by
making quiet sounds quieter. If the average (RMS) level of the signal is below the
threshold, the expander will smoothly reduce the gain on the signal. The key to
using the Expander is to adjust the threshold to be just above the noise floor. This
component is useful in hot mic situations to reduce background noise transmission.
Audio Input
InSignal
Type Default Value
audio n/a
Description: The signal that will be filtered. This input is linked
into the component from somewhere else in the model.
Control Input
Attack
Type Default Value
float32 250.0
Description: Attack controls how quickly the gain changes in
response to an increase in signal level. For the expander, this means
it controls how quickly gain is restored to 1.0 when speech resumes.
Enable
Type Default Value
boolean True
Description: Controls whether any gain adjustment will occur.
Control Inputs
OutGain
Type Default Value
float32 1.0
Description: Gain applied after the expander stage.
Ratio
Type Default Value
float32 2.0
Description: Controls how aggressively sounds below the threshold
are reduced in volume. A ratio of 2.0 (2:1) means a signal of 1 dB
below will exit the component 2 dB below.
Release
Type Default Value
float32 50.0
Description: Release controls how quickly the gain changes in
response to a decrease in signal level. High releases will cause a
quick reduction in background noise when speech stops.
Threshold
Type Default Value
float32 -55.0
Description: The level in dB below which expansion (gain
reduction) will take place. Adjust the threshold to be just above the
loudest sound that should be reduced in volume. Often times this
corresponds to just above the background noise level.