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AM-10HD / Aug 2008
A M - 1 0 H D G U I
AUTOMATIC GAIN CONTROL and COMPRESSOR MENU
The AM‑10HD AGC and Compressor sections are inextricably linked by DSP
algorithms that logically connect them. Therefore they will be covered collectively
in one chapter rather than discussed separately.
Although the AGC and Compressor sections’ outputs may be separately enabled
or disabled, the Compressor algorithm is
always
running so that the derivative control
signals are available to the AGC section.
The automatic gain control (AGC) operates in five frequency bands and its long‑
term operation is a special derivative of the type of program‑related processing oc‑
curring in the Compressor algorithms. The AGC and Compressor operate in Sum
and Difference mode – the highest signal, whether in the sum or difference channel,
determines the amount of processing to be applied to both channels.
Drive
The Drive control adjusts the amount of signal into the AGC/Compressor, primarily
determining the amount of compression that can be achieved. Driving harder (higher
numbers) results in a more consistent on air sound, with an increased capability to pull
up low passages in program material. Less drive creates a more “gentle” on air sound
and has less capability to bring up low passages. The Drive control simultaneously
adjusts the sum and difference channels. The range of this control is from ‑79.0dB to
+6.0dB, or OFF when fully down.
NOTE: All Factory Presets use a setting of “0” for the AGC Drive, other adjust‑
ments having been made to achieve the desired sound.
L‑R Trim – The List box below the Drive control contains the trim adjustment
for the Difference, or L‑R, channel, and may be ad/‑ 6dB referenced to the
Drive control. In other words, if the Drive control is set to +4.0dB and the L‑R trim
to ‑5.0dB, the difference channel drive is actually ‑1.0dB.
Makeup
This control adjusts the overall output level of the AGC/Compressor into the fol‑
lowing stages. It simultaneously adjusts the Sum and Difference channels. The range
is from ‑20.0dB to +48.0dB.
Because all bands of the AGC/Compressor utilize a feed‑forward design, the
loss of signal amplitude created while the input signal undergoes compression must
Five Band AGC / Compressor Screen
