4
5
sTeReO RHYTHM DeLAY seCTiON
The stereo rhythm delay line has 16 time-delayed taps, each with its own resonant 2nd-order multi-mode
state-variable filter and granular pitch shifter. The filters have independently adjustable resonance and cutoff fre
-
quency, and can be set to either lowpass, bandpass, highpass or bypass operation. The granular pitch shifters have
a range of 15 semitones up to 16 semitones down.
Any one of the 16 taps can be selected to be fed back to the input for echo or regeneration effects. The feedback
signal has a first order lowpass/highpass tone control filter and its own granular pitch shifter.
The tap delay times can range from 0.1 millisecond up to a maximum of 20 seconds. The overall delay times can
be set either by manual entry with the rotary encoder, with a tap tempo entry, or through an external clock. The
relative timings of the individual taps are set to one of 16 different preset “grooves”, or rhythms. The overall delay
time can be modulated with an internal low frequency oscillator (LFO) with adjustable wave shape.
sTeReO ResONANT COMB fiLTeR seCTiON
The stereo comb resonator section has 64 time-delayed taps which are summed together. This produces a deep
comb filter or resonating effect. At large comb sizes (long time delays) a multiple echo effect is produced. The den
-
sity of the resonator can be varied from 1 tap all the way up to 64 taps.
The relative timing of the 64 taps are set according to one of 16 different preset patterns, which provide different
resonator timbres or echo rhythms. The comb size can be set either with the rotary encoder, an external clock
or through a transposable 1v/oct input voltage. The comb size can be modulated with an internal low frequency
oscillator (LFO) with adjustable wave shape.
The tap with the longest delay time (tap 64) is fed back to the input. The amount of signal being fed back is adjust
-
able. High feedback levels, with short comb sizes, can produce “Karplus-Strong” types of plucked string sounds.
The feedback signal passes through a simple fixed low pass filter and a selectable nonlinearity. The nonlinearity
can provide a different quality to the resonant sound when the feedback level is high.
Comb Delay Line
1 2 3 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 64
Feedback is taken
from Tap 64
Quadrature
Mod. LFO
Feedback Filter
COMB
FEEDBACK
LEVEL
COMB
FEEDBACK
NONLINEARITY & FILTER
Level Rate Shape
SLOPE
COMB INPUT
COMB OUTPUT
Tap Selection Switches
#TAPS
COMB SIZE
TAP PATTERN
Rhythm Delay Line
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feedback Tap
PS1
PS16
Quadrature
Mod. LFO
Pitch Shifter
Tone Filter
DELAY
FEEDBACK
LEVEL
FEEDBACK
TONE
FEEDBACK PITCH
SHIFT + DETUNE
Level Rate Shape
Pitch Shift, Detune
Pan/Balance
Level
Mute
Cutoff Frequency
Resonance (Q)
Type
PITCH SHIFTERS
STEREO PAN/BALANCE CONTROLS
MULTI-MODE (LP, BP, HP) 2nd ORDER FILTERS
PB1
PB16
F1
F16
RHYTHM DELAY INPUT
RHYTHM DELAY OUTPUT
CROSSFADER
WET/DRY
Figure 1.
Rhythm delay section block diagram.
Figure 2.
Comb resonator section block diagram.