Polycom SoundStructure C16 Design Manual page 123

Hold Time
Hold Time specifies the amount of time a channel remains active after the last detected significant signal
level. This should be set long enough to remain active during short pauses in speech.
Camera Activity Time
Camera Activity Time specifies how long the microphone must be considered active before a camera
indicator is set. The camera indicator is a status message that can be used with an external control system
to indicate that a particular microphone is active. Shorter times mean the indicator is easier to set based on
local talker activity. Longer times mean that it takes longer before the camera gating activity indicator is
triggered.
Priority Attenuation
Each automixer group can have a priority attenuation setting, in dB. A value of 0 means the higher priority
microphone comes first in the ordering of which microphones to gate on, but does not otherwise attenuate
a lower priority microphone. A priority attenuation value greater than 0 causes the lower priority
microphones to be attenuated (in addition to any NOM limit effects) by the priority attenuation when a higher
priority microphone is active.
Gain-sharing automixer groups can use the priority attenuation to simulate a "soft chairman'' priority
ducking.
Off Attenuation
Off Attenuation is the amount of attenuation applied to gated channels when they are not active. This should
be set high enough that inactive channels don't contribute too much noise and reverberation to the mix. The
ideal value for this parameter may increase with the number of microphones in the system. The default value
is 15 dB.
Decay Time
Decay time is the amount of time a gated channel takes to ramp its gain down from open (0 dB) to its off
attenuation. This should be set long enough to provide a smooth transition as the talker stops speaking.
Gating Indicators
Channel activity status (the gate light for each microphone) is available for microphones regardless of
whether they are in a gain sharing automixer group or a gating automixer group. The gating status lights
can be useful for output to channel activity LEDs via the logic outputs and control system displays.
Camera activity is similar to channel activity, but has some additional time that the microphone must be
gated before the camera gating indicator is made active. The camera gating status is intended to be used
with logic outputs or control systems that interface to a camera positioning system that can have various
presets according to which microphones are active.
Adaptive Threshold
Adaptive threshold is the level in dB relative to its noise floor a signal must have to be eligible to be
considered active. Higher settings makes the channel less sensitive - harder to turn the microphone on,
while lower settings make it more sensitive - easier to turn the microphone on.
Polycom, Inc. 123