CHAPTER 23. LIVE INSTRUMENT REFERENCE
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23.6.2
Start, Tune and Stretch
The Start control de nes where Impulse begins playing a sample, and can be set up to
100 ms later than the actual sample beginning. The Transposition control adjusts the
transposition of the sample by +/- 48 semitones, and can be modulated by incoming note
velocity or a random value, as set in the appropriate elds.
The Stretch control has values from -100 to 100 percent. Negative values will shorten the
sample, and positive values will stretch it. Two different stretching algorithms are available:
Mode A is ideal for low sounds, such as toms or bass, while Mode B is better for high sounds,
such as cymbals. The Stretch value can also be modulated by MIDI note velocity.
23.6.3
Filter
The Filter section offers a broad range of lter types, each of which can impart different
sonic characteristics onto the sample by removing certain frequencies. The Frequency
control de nes where in the harmonic spectrum the lter is applied; the Resonance control
boosts frequencies near that point. Filter Frequency can be modulated by either a random
value or by MIDI note velocity.
23.6.4
Saturator and Envelope
The Saturator gives the sample a fatter, rounder, more analog sound, and can be switched on
and off as desired. The Drive control boosts the signal and adds distortion. Coincidentally,
this makes most signals much louder, and should usually be compensated for by lowering
the sample's volume control. Extreme Drive settings on low-pitched sounds will produce
the typical, overdriven analog synth drum sounds.
The envelope can be adjusted using the Decay control, which can be set to a maximum of
60 seconds. Impulse has two decay modes: Trigger Mode allows the sample to decay with
the note; Gate Mode forces the envelope to wait for a note off message before beginning
the decay. This mode is useful in situations where you need variable decay lengths, as is the
case with hi-hat cymbal sounds.
