User`s manual

Page 30
changes suddenly, requiring a new filter solution; this may occur when the
microphone is moved, or when processing tape recorded conversations that
occurred at different locations.
6.3 Highpass Filter
The Highpass filter is used to attenuate all signal frequencies below a specified
cutoff frequency. This filter is used to reduce low-frequency noises, such as tape
or acoustic room rumble, from the input audio. The Highpass filter is sometimes
called a "rumble filter."
Figure 6-3 shows the filter configuration window for the Highpass filter.
Figure 6-3: Highpass Filter Dialog
The only adjustable setting available for the Highpass filter is the cutoff
frequency. Any signal frequencies below this cutoff frequency will be attenuated.
6.4 Automatic Gain Control
The Automatic Gain Control, or AGC, is used to boost low-level output signals to
a good listening level. The AGC monitors the signal level, and if it drops below a
minimum reference level, gain is gradually applied to bring the signal back up to
the reference level. The gain continues to be applied until the signal level again
rises above the reference level or until the maximum allowable gain is applied. If
the output signal level is above the reference level, the AGC has no effect on the
output audio.
Figure 6-4 shows the filter configuration window for the Automatic Gain Control.