TRHILO

HI-LO

Trident Audio

Make it easier than ever to clean up your recorded audio with the Hi-Lo Tracking Filters from Trident Audio, an analog 500-series rack module that sports two dynamic, program-adaptive tracking filters, one high-pass and one low-pass, for quickly cutting out unwanted rumbles, hums, and general noise like tape hiss. Both filters are sweepable and sport resonance peak control, selectable slopes between 12 and 24 dB per octave, and red LEDs for peak indication.The Hi-Lo Tracking Filters feature an extremely wide frequency response and sweeping range, capable of tackling virtually any audio material and allowing for unique effects to be achieved when combined with high resonance settings. The module supports stereo linking with a second Hi-Lo for stereo filter processing, series wiring for a nearly unlimited range of filter slopes, and built-in support for the mixing facilities of the API Radial Workhorse chassis.The Hi-Cut This is a sweepable low-pass filter with unity gain in the selected passband and a selectable (12 or 24 dB per octave) roll-off outside the passband. The cutoff frequency can be set from 75 Hz to 24 kHz.In addition, a Resonance control can be switched into circuit, to introduce a resonant peak at the selected cutoff frequency. The size of this peak, which is dependent on the elected frequency selected on the front panel, can be varied from zero to approximately +12 dB. A Hi-Cut Enable switch allows each individual frequency band or filter to be assessed, while a red Peak warning indicator will illuminate at around +16 dBu, approximately 12 dBu below clipping.The Lo-Cut This is a sweepable high-pass filter with unity gain in the selected passband and selectable (12 or 24 dB per octave) roll-off outside of the passband. The cutoff frequency can be set manually, anywhere from 15 Hz to 16 kHz.In addition, a Resonance control can be switched into the circuit, to introduce a resonant peak at the selected cutoff frequency. The size of this peak, which is dependent on the elected frequency selected on the front panel, can be varied from zero to approximately +12 dB. A Low-Cut Enable switch allows each individual frequency band or filter to be assessed, while a red Peak warning indicator will illuminate at around +16 dBu, approximately 12 dBu below clipping.Dynamic Tracking Using the Track Signal function, enables the Lo-Cut or Hi-Cut filter to be used for a dynamic hum and rumble reduction (Lo-Cut) or general noise reduction (Hi-Cut). This is a technique that relies on the psychoacoustic effect of masking, in which a louder signal will cover up a quieter signal of the same frequency. In this mode, the cut-off frequency dynamically tracks the low- or high-frequency content of the music, with the frequency control setting the frequency to which the filter will open up in the absence of any low- or high-frequency content.Further Filtering Possibilities Use of higher resonant settings will result in the movement of the filter becoming audible and indeed, combined with the lower settings of the frequency control, this can be the basis of some unique special effects. The sweep range of the filters are extremely wide, from effectively subsonic/ultrasonic, right up/down to full audible bandwidth. This suggests the possibility of fading tracks in and out, not in the amplitude domain as is usual, but in the frequency domain.Dynamic Linked Stereo Tracking The Trident Hi-Lo module also offers the option of linked stereo tracking when paired with a second Trident Hi-Lo module. The Trident Hi-Lo provides an onboard stereo link switch (S9) for use in this instance. With both modules, stereo link switches selected to on, and the modules fitted in the pre-paired slots, the modules are now paired together.By enabling both Hi-Lo modules Track Signal switches, and setting the frequency controls to identical positions, the left and right signals are now summed together, and the automatic tracking follows both the left and right signal sourc