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D. Live Pitch Shift
This very new feature of the Reflex adds yet another "live" option to use the sampling engine. Using a pitch-shift
is especially great with vocals (matching a key) or drums (changing the timbre). The Pitch-Shift mode also allows
the variance of tempos without shifting the frequency i.e. sample rate. This can be used to add some "swing" to a
beat, especially a snare if can be fed alone into the Reflex, by varying the Pitch-Shift delay parameter which gives
it a "human" quality.
This addition simply uses the G-Move PlayFX mode in a different way:
1) Set the Rate to center, feedback all the way down, and select R/P or Echo mode
2) Use PSEL to select the G-Move PlayFX mode (blue LED)
3) Tap the REC button to start a record, then tap the PLAY button to start PlayFX
4) With audio feeding in, try adjusting the Rate control to pitch-shift the audio.
Knobs:
The bottom PlayFX knob will act as usual, setting the G-Move size, but the top knob will act very
differently. It now controls a delay, from near zero to 1 second. The tighter the G-Move, the shorter
the delay from "real time" will be.
Rate:
You may have noticed the Rate knob is acting differently since entering Pitch-Shift? This is because the
range has been reduced to 1.25 octaves, giving better control over the useable range. The +/- 1 LEDs will
indicate exactly 1 octave.
CV inputs:
-The bottom CV (END/SIZE) will control the grain size as usual, adding to the knob.
-The top CV jack (ST/GM/POS) becomes a +/- 5V offset for the top knob. This allows the
delay to be moved either way from the present knob position, and is very useful for
staggering delay sizes, thus adding a "swing" to the incoming audio, without shifting
the sample rate at all.
-The Rate CV can shift over the 1.25 range but add on up to 5 octaves each way as usual.
Feedback on Pitch-Shifting:
Turning up the feedback will yield some bizarre/dirty arpeggio's going up/down that can totally
become a sound of it's own!
*Remember, to make Slices of this, you'll need the feedback up, or you'll just record incoming audio!
Tech Stuff:
The reason the feedback sounds choppy after a few rounds is the zero-crossing in G-Move.
Each time a grain loops, there's a 4mS "gap" in the sound. The feedback sends this audio and gap back
into the sampler's input to have another gap added when that grain loops. It's unavoidable as it's either
gaps or clicks (no zero-crossing). The length of a grain can't be continuously varied without artifacts,
so there's no matching the wave form "edges". In a large DSP system (computer, ARM DSP) these
bridges are averaged, or "faked" to add smoothness, leaving an unauthentic blur of sound if fed back
upon itself. It's just the nature of audio.
Exiting Live Pitch-Shifting:
As this mode only works during an initial Record, continuing as a normal G-Move over the long sample
recorded can be accomplished by holding the REC button to stop it, or tapping REC to play/echo.
This can allow some reversing over the last recorded sample with G-Move.
*The proper way to exit though is to hold the PLAY button or turn off the PlayFX LOOP LED
