Setting Up The Processing
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Delay
The delay control sets the amount of time the processor will hold the gain reduction for before releasing at the
peak decay rate. Careful setting of this control allows us to speed up the peak decay time without introdudc-
ing the audible effects of faster decay times. Setting this control to 1 is a neglible amount of delay before decay
which is equivalent to the delay being switched out of circuit. As you go up through the bands you will need
lower delay numbers to avoid causing audible problems being introduced by the delay circuit. We have found
that bands 3 and 4 work well with settings of 2-4, band 2 settings for 3-6 and band 1 settings of 5-8. Setting the
control to 10 introduces almost half a second of delay before decay so make sure you don’t use the higher set-
tings of this control on anything other than band 1.
If you are unsure about this control we suggest you set it to 1 to turn it OFF.
Band-couplings
The DSPX band-coupling controls allow us to reduce the effects of the multi-band processing by coupling the
bands to a certain extent. This may be desirable if we want to limit the re-equalisation effects of the multi-band
AGC and limiters. By carefully selecting the coupling ratios we can also reduce any possible spectral skewing
when the processing stages are driven into heavy gain reduction. The multi-band AGC and limiters each have
there own band coupling controls
The coupling control controls the amount of audio that is fed from one bands detector into the neighbouring
bands detector. The audio is fed from one bands detector through the coupling ratio control and then the highest
level wins.
For example, if we coupled band 2 to band 1 with a coupling of 50% we would ensure that the band 1 gain
reduction could never decrease (less gain reduction) more than 6dB past the band 2 gain reduction. If the cou-
pling was set to 100% then the band 1 gain reduction would follow the band 2 gain reduction when the band 1
gain reduction would have been less than the band 2 gain reduction. Setting the coupling ratio to 0% would let
both bands operate independently of each other.
We can limit the amount of low and high frequency re-equalisation by carefully setting the B1<2 and B4<3 cou-
pling controls. If lighter processing is desired it is common to link the bands to a certain amount, where pop and
CHR formats usually desire low or uncoupled ratios. Coupling ratios around 30% are usually a good compro-
mise to maintain cut-to-cut consistency through multi-band re-equalisation while maintaining most of the original
spectral balance of the source material.
Channel coupling
The control allows you to gang the left and right channel gain controls by a percentage set by the control. If set
to 100%, the coupling works on a highest level wins basis where the channel with the maximum gain reduction
controls the gain reduction of both channels. This preserves the stereo balance of the original source material.
The control can be adjusted all the way down to 0% at which point the two DSPX becomes two totally indecent
processors (if the channel coupling in the AGC is set to 0% also). This is often known as a dual-mono architec-
ture.
While we would prefer you to buy two processors you could use a single DSPX as two processors, processing
two mono audio feeds. You would need to bear in mind if running the DSPX this way that the front panel gain
reduction metering may not behave as expected because the displayed gain reduction value for that processing
block is the highest gain reduction of the left and right channels.
Without hold
with hold
