INSTALLATION AND CONFIGURATION | 25
Call Audio Processing page - Audio Processing and metering
The VX has dynamics processing on both the send (from studio, to caller) and receive (caller)
audio directions. Adjustments and meters are on the hybrid page.
We recommend as a starting point +8 on the high EQ, +6 on the low EQ, 16 on the AGC (full),
the caller ducking to 6dB, and the noise gate off.
The send processing consists of a limiter and EQ. The purpose of the limiter is to protect
the Telco line from the distortion that would result from clipping due to an audio overload.
Livewire studio audio has a much larger dynamic range than telephone lines. We use a limiter
rather than an AGC because we don’t want the system to increase low-level signals, which
could cause feedback and sound unnatural to the caller.
The receive processing includes ducking, an AGC, and dynamic EQ.
Hybrid refers to the the traditional hybrid cancellation function; the removal of the send audio
from the received caller audio, required due to the nature of analog Telco lines, where the two
signal directions are combined on one circuit. In the VoIP world this should be done in the
gateway, and is not required in the phone system itself, but we use the term “hybrid” here
because it’s instantly understood. Some PBXs refer to the hybrid as an ‘LEC’ or Line Echo
Canceller.
The Call Audio Processing button allows you to enable or disable all of the audio processing
features of VX, such as AGC, EQ, ducking, etc., all at once. Enabling this option will let you
adjust the individual options below.
Ducking. The purpose of this is both to improve the performance of the system with regard to
feedback and echo as well as to provide an effect that many DJs and talk show hosts prefer –
that the caller level is reduced when they speak. The ducker reduces the gain in either the send
or receive path depending on who is talking at a given moment. There is a smoothing filter
with time-constants tuned to make the effect as natural as possible. The amount of ducking is a
user-adjusted variable value and may be defeated entirely if you choose.
To Next Page
Loading...