Kurzweil K2661, Справочник музыканта

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KDFX Reference
KDFX Algorithm Specifications
10-37
135 Spectral 4-Tap
136 Spectral 6-Tap
Tempo based 4 and 6 tap delays with added shapers and resonant comb filters on each tap
PAUs: 2 for Spectral 4-Tap
3 for Spectral 6-Tap
Spectral 4 Tap and Spectral 6 Tap are respectively 2 and 3 processing allocation unit (PAU) tempo based
multi-tap delay effects. They are similar to a simple 4 and 6 tap delays with feedback, but have their
feedback and output taps modi
fi ed with shapers and fi lters. In the feedback path of each are a diffuser,
hipass fi lter, lopass fi lter, and imager. Each delay tap has a shaper, comb fi lter, balance and level controls
with the exception of Tap 1, which does not have a comb fi lter (Figure 1).
Diffusers add a quality that can be described as “smearing” 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 fi lters are also in the feedback path: hipass and lopass. The hipass fi lter roll-off
frequency is controlled with LF Damping, and the lopass fi lter 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 Musician’s 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
fi lters tuned in semitones. These comb fi lters make the taps become pitched.
When a comb fi lter is in use, the shaper before it can be used to intensify these pitched qualities.
Each tap also has separate balance and level controls.
Since these are tempo based effects, tap delay values and feedback delay (labeled LoopLength on
PARAM2) values are set relative to a beat. The beat duration is set be adjusting Tempo in BPM. The tempo
can be synced to the system clock by setting Tempo to System. Each tap’s delay is adjusted relative to 1
beat, in 1/24 beat increments. Notice that 24 is a musically useful beat division because it can divide a beat
into halves, 3rds, 4ths, 6ths, 8ths, 12ths, and of course 24ths. For example, setting LoopLength to “1 12/
24bts” will put the feedback tap at 1 1/2 beats (dotted quarter note in 4/4 time) of delay making the
feedback repetition occur every one and a half beats. This is equivalent to 3/4 of a second at 120 BPM.