BSS Audio FDS-388 OMNIDRIVE Owner's Manual - Manual (Page 31)

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10.1 Dynamic Filter.
EQ Utility Screen
Fig 10.1 Dynamic EQ
with a Boost Filter
Fig 10.2 Dynamic EQ
with a Cut Filter
The dynamic filter works in one of two distinct ways depending on whether the
filter selected is in boost or cut mode.
As an increasing signal level approaches the dynamic threshold, the boost
value of the filter is progressively reduced until the filter is flat when the signal
level reaches the dynamic threshold.
As an increasing signal level approaches the dynamic threshold, the cut value
of the filter is progressively increased from flat until the filter is at its full cut
value when the signal level reaches the dynamic threshold.
Both functions serve to reduce the filter level as the overall signal level in the
band increases.
The threshold for the dynamic filter is set relative to the band limiter. The ratio
of the filter cut/boost adjustment is preset to 2:1. The first graph below (fig
10.1) shows the relationship between the signal level and the filter level with a
boost filter. The example shown has the dynamic threshold set to -10dB below
the limiter threshold and a filter boost of 6dB. As the signal level is increased
from low levels the filter boost is constant at 6dB until 22dB below the limiter
threshold. With each 2dB increase in signal level the filter boost is decreased
by 1dB until the signal level reaches the threshold at which point the filter is
effectively flat. As the signal level continues higher, the filter boost remains at
0dB.
The second graph (fig 10.2) shows a cut filter, again with a 6dB cut and a -
10dB threshold. As the signal is increased from low levels the filter now stays
flat until 22dB below the limiter threshold. With each 2dB increase in signal
level the filter cut is increased by 1dB until the signal level reaches the thresh-
old at which point the filter at 6dB of cut. Increasing the channel level further
holds the filter at 6dB of cut.
In boost
In cut