Trident 500 Series - Overview of Hi-Cut Filtering; The Hi-Cut Filter; Hi-Cut Dynamic Tracking

1 Trident Audio Developments | Hi-Lo Dynamic Filtering User Manual 2Trident Audio Developments | Hi-Lo Dynamic Filtering User Manual
Trident
500 Series
Hi-Lo
Dynamic
Filtering
No Ordinary
Filtering
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The Trident Hi-Lo, an adaptive Hi-Cut/Lo-Cut frequency filtering module
that responds dynamically to program material, providing a high degree
of control and signal enhancement, unavailable in any modern day 500
series package.
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— OVERVIEW —
The Hi-Cut
This is a sweepable low pass filter with unity
gain in the selected pass band and a select-
able (12dB per octave or 24dB per octave) roll-
o outside the pass band. Cuto frequency
can be set from 75Hz to 24kHz.
In addition, a RESONANCE control can be
switched into circuit, to introduce a resonant
peak at the selected cuto frequency. The size
of this peak, which is dependant on the elect-
ed frequency selected on the front panel, can
be varied from zero to approximately +12dB.
At maximum setting, RESONANCE stops just
short of self-oscillation.
A HI-CUT ENABLE switch allows each individ-
ual frequency band or filter to be assessed, while a red PEAK warning indi-
cator will illuminate at approximately +16dBu, approximately 12dBu below
clipping. To allow adequate headroom, avoid boosting the signal by more
than an amount which just causes this LED to flash on occasional peaks.
Hi-CUT Dynamic Tracking
Using the TRACK SIGNAL function enables the Hi-Cut filter to be used
for dynamic noise reduction. This is a technique which relies on the
psychoacoustic eect of ‘masking’, in which a louder signal will cover up
a quieter signal of the same
frequency. In this mode, the cuto frequency
tracks dynamically the high
frequency content of the music, with the FRE-
QUENCY control setting the frequency to which the filter will close down
in the absence of any high frequency content.
With a noisy signal applied (e.g. from analogue tape or other material
with a high background noise content), start with the FREQUENCY con-
trol at maximum (fully clockwise) and back o the control until the noise
just disappears.