4U032 - ResEQ
The RESONANT EQUALIZER (EQ) is a unique ten-band filter designed specifically
for electronic sound synthesis and processing.
Except for the top and bottom frequency bands, all other bands are spaced at an
interval of a major seventh.
This non-standard spacing avoids the very common effect of an accentuated resonance
in one key, as will be the effect from graphic equalizers with octave or third-octave
spacing between bands.
Spacing by octaves will reinforce a regular overtone structure for one musical key,
thereby producing regularly spaced formants accenting a particular tonality.
The ResEQ's band spacing are much more interesting, producing formant peaks and
valleys that are similar to those in acoustic instrument sounds.
There are three equalized outputs, two which mix the alternate filter bands
and one which is a mix of all filter bands.
The upper (up arrow COMB) lets pass the outputs of frequency bands at 61 Hz, 218 Hz,
777 Hz, 2.8 kHz, and 11 kHz.
The lower (down arrow COMB) mixes the other bands at 29 Hz, 115 Hz, 411 Hz,
1.5 kHz, 5.2 kHz.
This equalizer is different from other equalizers in that the bands can be set to be
resonant.
When the knobs are in the middle position, the response at the main EQ Output is flat.
When the knobs are positioned between the 9 and 3 o'clock position,
up to 12 dB of boost or cut is set at the band.
If the knob is set beyond the 3 o'clock position, the band will become resonant,
simulating the natural resonance of acoustic instrument formant structures.
Below the 9 o'clock position, increased band rejection is achieved.
PCB:
1.6 mm thick, double sided, green
base material FR4-Standard TG 135-140
surface finish HASL
part values are silkscreened
all panel mount!
Front panel
1.6 mm, PCB material with colour front print that "mimics aluminium"
2" x 175 mm
mounting holes - 3.5 mm, follows the LW specification (top and bottom)
please note, minor imperfection may occur
no parts, just the PCB and panel
Documentation
