Solidyne 462dsp, User Manual

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Page 20
SOLIDYNE 462
dsp - broadcast digital processor
4.4 PROGRAM ADJUSTMENTS
The screen “Edit Program” shows the blocks
diagram of the processor, showing the main
stages involved in the audio processing. The
operation is the same one that in other screens.
Turn the JOG to select a stage and touch briefly to
enter.
LISTENING ON THE EDITION
•
Next we will see the different forms to create or to modify
the sound of a program. Each change that we make will
listen on the air. Therefore we will have to listen carefully
with a good receiver (better still tuning Walkman or and
an audio amplifier of high quality, with good
loudspeakers). Not to listen the signal directly from the
audio output of 462dsp, but the air signal of the
trasmisor
4.4.1 PROGRAM NAME
Allows change the program name. Press briefly on
this option to enter to the edit mode.
•
The characters are changed turning the JOG. To
confirm press briefly the JOG.
•
To confirm the changes, press and hold on OK.
•
To cancel and leave this screen, press and hold on
any character.
4.4.2 EXPANDER / AGC
4.4.2.1 AGC OUT GAIN
The output level of the AGC is a CRITICAL
ADJUSTMENT, since it determines the level with
the signal reaches the multiband compressors,
and therefore the compression degree that will be
applied.
So the action of the multiband compressors fits
using the output level control of the AGC.
LOUDNESS
BANDS indicators show the
compression degree applied by the multiband
system. Each band has its own indicator.
Usual values for the AGC output are between +6
to +12 dB.
TAKE IN MIND
•
How much greater the compression degree is, more
loudness has the program on the air. But high
compression levels (greater than 18 dB) can produce a
“confused” sound in certain type of music (hyper-
processed, of high density) and excessive alteration of the
timbre (with soloists’ voices or instruments). For this
reason it's a critical adjustment and you must pay special
attention to this control.
4.4.2.2 AGC attack time
The attack time is the time that the AGC takes to
reduce its gain when the input signal increases.
Like general rule, it can say that for voices short
times of attack must be used (500 ms); whereas
for music longer times are preferred (3 to 4
seconds).
Note that when the input signal increases quickly,
during the AGC attack time the signal is contained
by the multiband compressor that will act strongly
until the AGC compensates their level. Depending
on the adjustments of the following stages, a too
slow attack of the AGC can cause an excessive
compression of the signal (mainly with voices)
4.4.2.3 AGC recovery time
When the input signal decreases, the AGC begins
to increase their gain to compensate the fall of
level at the input. Remember that the objective of
the AGC is to assure that the signal reach the
processing stages with a very stable level;
independent from the console's level. The time
that takes the AGC in compensating the gain
reduction is called recovery time.