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AM-55 / Sep 2015
A M - 5 5 G U I
The controls along the top of the grid (outlined here in red) allow you to select the
parameter you wish to adjust. Those parameters are described below:
Threshold
The Thresh
control determines at what level processing will begin to take effect in
a particular leveller band. Higher threshold settings cause processing to begin at higher
levels and lower threshold settings cause processing to begin at lower levels. The range
for the AM‑55’s AGC Threshold controls can be /‑ 6dB from their 0dB reference
Leveller Attack
The Levlr Att
control determines how quickly the leveller will respond to upward level
changes in the audio. The control range is 50ms to 500ms. A setting of 300ms corresponds
well to our perception of average loudness and is therefore a very good starting point.
Leveller Release
The Levlr Rls
control determines the rate at which the Leveller will increase gain when
the audio levels fall, as long as they are still above the Gate Threshold setting discussed
previously. The adjustment range of the control is from 1.0 seconds to 7.0 seconds. The
7 second setting is considered VERY slow and is recommended for fine‑arts or classical
programming (or, if you’re Jeff Keith, for Classic Rock processing when he wants the
on‑air dynamic range to mimic the old AOR formats). The 1 second setting is very fast
and is recommended only if a certain “pumpy” texture is desired. The recommended
setting for most formats is between 2.5 seconds and 6 seconds.
Density
Adds energy into each band of processing to add consistency and loudness. The density
control range is 0‑6 with higher numbers adding more consistency to each band.
Compressor Attack
The Comp Atk
control determines how quickly the Compressor responds to rising au
‑
dio levels not caught by the Leveller because of its longer attack time. The compressor’s
purpose is to handle medium term peaks only, and by doing so it completely frees the
AGC from having to worry about controlling them.
