Grass Valley AMX-3981 2014 - Manual (Page 42)

GUIDE TO INSTALLATION AND OPERATION
36 | AMX-3981
Use the Ratio pulldown to set the compression ratio (i.e. slope of the transfer curve). The compression ratio specifies
how much the output level changes with respect to the input level:
• Possible values: 1/1 (OFF), 1/1.25, 1/1.5, 1/1.75, 1/2, 1/3, 1/4, 1/8, 1/16
Use the Threshold slider to set the compression threshold (i.e. break point in the transfer curve). The compression
threshold specifies the level above which the compressor will process the signal.
• Range -60 dB to 0 dB
Expander
Audio expansion means to expand the dynamic range of a signal. It is basically the opposite of audio compression.
Like compressors and limiters, an audio expander has an adjustable threshold and ratio. Whereas compression and
limiting take effect whenever the signal goes above the threshold, expansion effects signal levels below the threshold.
Any signal below the threshold is expanded downwards by the specified ratio.
For example, if the expander threshold is set to -40 dBFS and a ratio of 2/1, and the input signal level is -60 dBFS (20
dB below the threshold), the signal level at the output of the expander will be reduced to -80 dBFS. Then, if the input
signal level suddenly increases to -30 dBFS (10 dB above the threshold), the signal level at the output of the
expander will go back to -30 dBFS.
Use the Ratio pulldown to set the expansion ratio (i.e. slope of the
transfer curve). The expansion ratio specifies how much the output level
changes with respect to the input level :
• Options available: 1/1 (OFF), 1.125/1, 1.25/1, 1.375/1, 1.5/1,
1.625/1, 1.75/1, 1.875/1, 2/1
Use the Threshold slider to set the expansion threshold (i.e. break point
in the transfer curve). The expansion threshold specifies the level below
which the expander will process the signal.
• Range -80 dB to -40 dB
Dynamics for 1 minute.
Click the Dynamics for 1 minute button to display the dynamics processing in the meters at the bottom of the panel for
a period of one minute. Dynamics metering is enabled by groups of 16 channels: Channels 1-16 or Channels 17-32,
selected depending on the Channels tab selected at the top of the panel
• The right-hand portion of this section shows the output channels of the dynamics processor on level meters, as
found in the RALM panel.
Expansion Ratio & Threshold
1.25/1 & -60 dBFS 1.75/1 & -40dBFS
Figure 5.24 Dynamics for 1 minute display