Controlling Fader; Processing Delay - Polycom SoundStructure C16 Design Manual

For each of the 1 parametric filters, the designer can choose from:
● Parametric filter
● Notch filter
● Allpass filter
Parametric filters emphasize or de-emphasize the center frequency with a gain and bandwidth setting. The
user can specify the bandwidth (in octaves), center frequency (in Hz), and gain (from 0 to 20 dB).
Notch filters eliminate energy (attenuate only) at the center frequency. The amount of attenuation for the
signal is determined by the bandwidth (in octaves) selected. The bandwidth is defined as where the gain is
-3 dB.
Allpass filters do not modify the gain of the signal, but change the phase. For a second order allpass filter,
the phase shift is 0 degrees at 0 Hz, 360 degrees at high frequencies, and 180 degrees at the center
frequency. The bandwidth is defined as the bandwidth (in octaves) where the phase shift is 90 degrees and
270 degrees.

Controlling Fader

The fader control enables the user to add gain or attenuate the telephone signal from +20 dB to -100 dB
with a resolution of 0.1 dB. This gain is applied in the digital domain.
A maximum and minimum gain range can be specified for the faders to limit the user gain control. The
process of setting the min and max volume controls is described in the
There is a fader control on the phone input channel and a fader control on the phone output channel.

Processing Delay

The delay processing allows the designer to add from 0 to 1000 milliseconds of delay on both the telephone
input and output channels. While the delay is set in milliseconds in the user interface, it can be manually set
through the command API in samples where each sample represents 1/48 of a millisecond.
Polycom, Inc.
Controlling Fader section.
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