Kurzweil K2661, Musician’S Reference Manual

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KDFX Reference
KDFX Algorithm Specifications
10-61
occur smoothly. You can assign the static delay tap to a continuous controller and use the controller to do
manual
fl anging. Figure 4 shows the delay line for a single LFO.
Figure 10-22 Delay for a Single LFO
Consider a simple example where you have an LFO tap signal being subtracted from the static delay tap
signal. If the delays are set such that at certain times both taps are the same length, then both taps have the
same signal and the subtraction produces a null or zero output. The effect is most pronounced when the
static tap is set at one of the ends of the LFO excursion where the LFO tap motion is the slowest. This is the
classic Thru-Zero
fl anger effect. Adding other LFO taps to the mix increases the complexity of the fi nal
sound, and obtaining a true Thru-Zero effect may take some careful setting of delays and LFO phases. The
fl anger has a Wet/Dry control as well, which can further add complexity to the output as the dry signal is
added to various delayed wet components for more comb fi ltering.
When using more than one LFO, you can set up the phase relationships between each of the LFOs. The
LFOs of the left channel and the LFOs of the right channel will be set up in the same phase relationship
except that you may offset the phases of the right channel as a group relative to the left channel (L/R
Phase). L/R Phase is the only control which treats left and right channels differently and has a signi
fi cant
effect on the stereo image. If you have tempo set to the system tempo, the phases will maintain their
synchronization with the tempo clock. At the beat of the tempo clock, a phase set to 0° will be at the center
of the LFO excursion and moving away from the delay input.
Regenerative feedback has been incorporated in order to produce a more intense resonant effect. The
signal which is fed back is from the
fi rst LFO delay tap (LFO1), but with its own level control (Fdbk Level).
In-phase spectral components arriving at the summer add together, introducing a series of resonant peaks
in the frequency spectrum between the notches. The amplitude of these peaks depends on the degree of
feedback and can be made very resonant.
Cross-coupling (Xcouple) allows the signals of the right and left channels to be mixed or swapped. The
cross-coupling is placed after the summation of the feedback to the input signal. When feedback and cross-
coupling are turned up, you will get a ping-pong effect between right and left channels.
A lowpass fi lter (HF Damping) right before the input to the delay line is effective in emulating the classic
sounds of older analog fl angers with their limited bandwidths (typically 5-6kHz).
As stated previously, it is the movement of the notches created in the frequency spectrum that give the
fl anger its unique sound. It should be obvious that sounds with a richer harmonic structure will be
effected in a much more dramatic way than harmonically starved sounds. Having more notches, i.e. a
greater ‘notch-density’, should produce an even more intense effect. This increase in notch-density may be
achieved by having a number of modulating delay lines, all set at the same rate, but different depths.
Setting the depths in a proportianally related way results in a more pleasing effect.
An often characteristic effect of fl anging is the sound of system noise being fl anged. Various pieces of
analog gear add noise to the signal, and when this noise passes through a fl anger, you can hear the noise
“whooshing.” In the K2661, the noise level is very low, and in fact if no sound is being played, there is no
noise at all at this point in the signal chain. To recreate the effect of system noise
fl anging, white noise may
Tap Dly
Delay Input
Shortest
Delay
Longest
Delay
Center
of LFO
LFO Xcurs LFO Xcurs
Range of LFO