Kurzweil KDFX Manual page 98

Special Topics
Live Mode
Sustained Notes and Loops
If the incoming signal is a single, sustained pitch, like a saxophone note, then you can consider
the Live Mode keymap to be playing a normal, looped sound. In this case, the fact that an
upward bend jumps back a few seconds is no big deal because the sound hasnÕt changed much
during that time.
With this technique, melodies or chords can be played based on a segment of a live
performance. Keep in mind that, unless your incoming signal is a C, notes and chords played
on the K2500 keyboard will be transposed relative to the incoming pitch. Also remember that a
rhythm pitched an octave down will play at half the speed, while one pitched an octave up will
play twice as fast. Fifths produce a 3-against-2 pattern. To keep some sort of relative sync with
the live signal, you may want to experiment with re-triggering the notes, perhaps using the
arpeggiator, at some appropriate tempo.
If the passage you want to play is long, and the input signal isnÕt so longÑsay, the sax player
needs to take a breathÑyou may run into a problem as the K2500 tries to play the buffer where
the audio was interrupted. If the input signal is mono, you might be able to overcome this by
using a delay line to ÒholdÓ the signal. The delay line could be part of KDFX, or it could be an
external device, but either way its output is sent back to the K2500 through the unused Live
Mode input channel.
Chord Progressions
Record a few bars of block chordsÑall notes under C4Ñinto the sequencer, using a simple
quarter-note or half-note pattern. What sound you use doesnÕt matter. Now replace the
Program on the recorded track with the LiveMode Default Program. Play back the sequence
(you will probably want it to loop), and at the same time play single notes from an external
instrument into the K2500, in the same rhythm as your recorded chords. If you change the notes
on the instrument, the chords will transpose. If you play intervals or chords, you're on your
own as to the consequences!
Vocoding
There are a number of ways to achieve a vocoder-type effect using Live Mode and both VAST
and KDFX processing. While explaining the VAST programming involved is beyond the scope
of this discussion, we can suggest using a KDFX Pitcher algorithm to make a simple
monophonic vocoder-like sound.
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Another suggestion is to bring in a signal, put it through multiple bandpass Þlters, and control
the amplitudes of the various layers with sliders and a sequencer, thus providing a very crude
vocoderÑif you're really good with the sliders.
6-4
Make a studio with FXPreset 915 PitcherB on the FXBus which is receiving the Live Mode
signal.
Go into a Live Mode program, and on its KDFX page, assign this Studio to the program.
Now assign an FXMod to the Pitch parameter on the correct FXBus, with an Adjust value
of C0, Source set to GKeyNum, and a Depth value of 128ST. Also set the KeyTrk on the
KEYMAP page of the program to 0ct/key.