Solidyne 462dsp, User Manual

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SOLIDYNE 462
dsp - broadcast digital processor
with a 2:1 ratio will produce an increase of 1dB at on the output
when an increase of 2dB takes place in the input. In this case
the increase of signal on the output was half with respect to the
increase on the input. The level from which the compressor
begins to be not-linear calls “compression threshold”. When the
signal surpasses the threshold, the compressor begins to
work..
On the other hand, when the signal surpasses the threshold,
the compressor takes a time in “reacting” to modify its gain.
This time is denominated “attack time”; and during the attack
the relation input/output pass to be linear to work according to
the compression ratio.
When the input signal reduces, the compressor takes in
recovering its original gain, that is to say, during a short time it
continues compressing. This time is called “recovery time”.
In 462dsp the compression thresholds are the same
for all the bands, to not alter the sonorous balance.
The compression degree simultaneously adjusts for
all bands, changing the level with which the signal
enters to the compressors (AGC Output). As greater
is the level, greater is the compression. You can set
the attack and recovery times for each band.
Have in mind that the settings for the compressors
and density EQ's varies according to the type of
program material, reason why there isn’t a unique
adjustment 100% optimal for all musical styles. A
great feature allows remote control from the
automation PC (using software Solidyne Audicom7)
to change the processing program according to the
music style. Remember that VirtualRack 5 also allows
defining program changes according to a scheduling.
Next, a screenshot of the multiband compressor stage
and soon its description:
4.4.4.1 Attack times
It's the time that takes the compressor in acting,
once the signal overpasses the threshold. Slows
attack times gives more “impact” to the sound, but
greater will be the action of the limiters. This is
because the attack of the sound passes through
compressors and arrives at the limiters with high
level. The limiters contain the peaks by clipping, a
technique much more lasts that the compression.
With short attack times hard clipping is avoided,
but very short times can produce a sound too ´flat´
for certain musical styles.
The scales for attack times are different for each
band.
In order to define the attack times, you must
consider the type of material to process. Some
musical styles, like the rock & pop, tolerate a hard
processing (more clipping). This offers a great
sensation of dynamic range (depth of the sound).
For orchestral music, jazz, piano, agree to use
faster attack times
4.4.4.2 Recovery times
It’s the time that the compressor takes in
recovering its linearity as soon as the signal falls
below the threshold.
The recovery times also are key settings, to
produce the perception of dynamic range. In main
lines; if the recovery is slow the compressor
practically works continuously; and initial impulses
produced by the attack time are lost. That is to
say; the attack takes place the first time, but as
the compressor's gain does not recover, the
following attacks are fully compressed. In this
condition the attack time does not have any effect.
The attack time is responsible to generate
“sensation of dynamic range”.
In percussion this is not desirable. For example:
techno music requires short time of recovery time
in the low band, not to lose the attack of groove.
The compressor must recover so that each "beat"
is affected by the attack time.
In the highs band the same occurs. If the recovery
time is very slow, the attack does not take effect
and the loudness of the high band (a Hi-Hat, for
example) diminishes. Faster recovery times
increase the loudness of the highs and the
“brightness” of the sound, but it can be a little
rough sound for some musical styles.
Note:
The attack, like the recovery, has a scale for band LF
and M1 and another one for bands M2 and HF. Band SF
copies the scale from HF.
4.4.5 DENSITY EQUALIZER
This technique eliminates the problem of the
conventional console's equalizers, whose action
soon is canceled by the multiband processor
(since
it compresses what the equalizer
reinforces). The technique of Density EQ operates
in combination with the multiband compressor.
Therefore its adjustments are interactive.