subconscious communications model 53: voice tail price : $429.00

the vcf3 voice tail combines full-featured voltage controlled filters, voltage controlled amplifiers, mode switching and flexible jack routing, in a module that alternates between a concerted sub-system, and then, a collection of discrete audio modifiers.

filters:
three 4-pole (-24db/oct), low-pass filters, transistor ladder filter topology.
voltage controlled resonance with full frequency range, sustained oscillation.
filters route in parallel or are individually accessible,
each filter has switched alternate freq response mode.
voltage controlled level composites into the global mix fed the final vca stage or, diverts for discrete application from the fout jack.



mix vcas:
three (3), filter dedicated, voltage-controlled amplifiers,
vca's, with exponential control characteristic, set its filter output audio level.

final vca:
linear control response voltage controlled amplifier,
filter mix 'normals' to final vca input.
the final vca can be used independent of the filter mix with input into aux input.

switching:
filter switched to an alternate output response type. filter's one and three have high-pass alternatives, filter two has a band-pass alternative.
filter two can be alternatively coupled to the input of filter three, series connecting these filter channels for maximum roll-off or idiosyncratic filter responses.
three 'enable/disable' switches routes channel 1 frequency / resonance / level control voltage to those of filters 2 and 3.

jack routing:
audio input to filter 1 'normals' to the input of filter two and three unless these filters have an alternate signal plugged at input.
when filters two and three are coupled, filter two 'normals' to filter one input audio (filter 3 has filter 2 output audio),
control inputs to filter one 'normals' across filters two and three if their audio and control inputs are unplugged. as previously noted, switches disconnect this control routing.
plugging to a filters fout jack diverts that filter from the final vca mix into independent use.
if all three filters are used independently, there is no mix. final vca input originates at the aux input jack.
the mix of non-diverted filters can be independently used by plugging to the mix jack. this removes the filter mix from the final vca input. the aux input still inputs to the final vca.



panel control operation:
panel control potentiometers are 10v (+/-5vdc) control adjustments. this allows "truncation" of an envelopes release or treating uncompensating diode based envelope generators.
the manual knob setting is a voltage adding or subtracting with plugged voltage controls, allow slope truncation or base elevation, transposing across 10 octaves.

operational detail:
module width: 21hp
power requirement: 90ma
frequency range: less than 2hz to 16khz
filter frequency control: (+/-)5v ac/dc
audio input level: (+/-)5vac typical prior overdrive soft waveform distortion up to +/-8.5vac
resonance control: input 0 to 5v for typical operation; (+/-)10v (ac/dc) tolerant.
level control input: 0 to 5v for typical operation; (+/-)10v (ac/dc) tolerant.
vca control input: 0 to 5v for typical operation; (+/-)10v (ac/dc) tolerant.

why transistor ladder filters?
much has been written about the filter topology invented and first realized by dr. robert moog. this literature divides between analysis for the technological ingenuity of the design and speculation as to what makes them so well received and appreciated. subconscious communication's implementation exploits a filter that alternates between a subtle, often natural sounding timbral formant, to razor edge incising cacophony. the provisioning of three filters allows inter-patch signals to 'fan-in' to a complex patch as a mix, or independent aural events.

what are these alternate response types?
commonly multi-stage filters allow audio at different points of the circuit to be added/subtracted or otherwise treated to provide alternative transfer functions. the implementation of high-pass and band-pass filtering typically employed with transistor ladder filters are notorious for their asymmetrical and shallow slopes when compared to the consistent -24db low-pass response. it is precisely the deviation from more strict implementation that make these modes characteristically useful. the high-pass is really more of a variable 'bass-cut' while the introduction of resonance reduces the effectiveness of the bass-cut while allowing the resonant peak to dominate the audio. some implantations choose to disabled resonance in this mode. the subconscious communications implementation includes resonance as the per filter vca's provide flexibility for exploiting this mode, allowing multiple filters to provide multi-frequency formant effects or to allow the resonance to exist as a companion to input audio.

coupling filter's 2 and 3 allows a variety of responses from simple steepening of alternate response type slopes to variable window band-pass filtering.

samples:
no res single lp
reso 60% single lp
3 vco - no res - mix
f1 hi pass
vcf as lfo
no inp vcf as sound source
60's beach party
lp-lfo drives reso
coast to coast and all the ships at sea
f1-hp f2-bp f3-hp
model 53 - audio file 1 - ck