FXAlg #135: Spectral 4-Tap ¥ FXAlg #136: Spectral 6-Tap
Algorithm Reference-45
Diffusers add a quality that can be described as ÒsmearingÓ the feedback signal. The more a signal has been
regenerated through feedback and consequently fed through the diffuser, the more it is smeared. It requires two
parameters, one for the duration a signal is smeared, labeled Diff Delay, and the other for the amount it is smeared,
labeled Diff Amt. Positive diffusion settings will add diffusion while maintaining image integrity. Negative
diffusion amounts will cause the feedback image to lose image integrity and become wide. Short Diff Delay settings
have subtle smearing effects. Increasing Diff Delay will be more noticeable, and long delay settings will take on a
ringy resonant quality. To disable the diffuser, both Diff Delay and Diff Amt should be set to zero.
Two 1-pole 6dB/oct filtersÑhipass and lowpassÑare also in the feedback path. The hipass filter roll-off frequency
is controlled with LF Damping, and the lowpass filter roll-off frequency is controlled by HF Damping.
The imager (found on PARAM2) shifts the stereo input image when fed through feedback. Small positive or
negative values shift the image to the right or left respectively. Larger values shift the image so much that the image
gets scrambled through each feedback generation.
On each output tap is a shaper. For an overview of shaper functionality, refer to the section on shapers in the
K2500
Performance Guide
. The Spectral Multi-Tap shapers offer 4 shaping loops as opposed to 8 found in the VAST shapers,
but can allow up to 6.00x intensity (Figure 2). Immediately following the shapers on taps 2 and above are resonant
comb filters tuned in semitones. These comb filters make the taps become pitched. When a comb filter is in use, the
shaper before it can be used to intensify these pitched qualities.
Various shaper curves used in the Spectral Multi-Taps
0 .2 0 x
0 .1 0 x
0 . 5 0 x
1 .0 0 x
2 .0 0 x
6 .0 0 x