Teac GigaStudio 3 - Manual (Page 273)

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GigaPulse runs in one of two modes: Turbo Mode or Pure Mode. Pure Mode is a 100%
mathematically perfect convolution and is very CPU intensive.
Most common impulse responses would adequately fit into the 3 seconds available
for most musically useful spaces. Exaggerated case example of a 10 second long IR. The
recorded impulse response would end abruptly at the end of 3 seconds.
Most of the convolution is happening in the –80dB (and down) end of the dynamic
range.This results in spending a great deal of computational resources on portions of
source material that, even in a solo context, would be for all practical purposes inau-
dible.
GigaPulse uses pure convolution for the first 3 seconds of the affected signal. After
3 seconds the Tail Model takes over with a recursive type algorithm that analyzes the
convolved signal and its decay and matches it tonally continuing with the decay of the
signal.
Enable button:
Default state is on and is highly recommended.
Overlap:
The overlap control is a 0-127 min-max setting. Generally the better results are in the
higher numbers. It is a timing offset and crossfade parameter for the original impulse
response convolved with the source material to the tail model portion of the processed
signal.
Level:
Adjust to match the levels of the original signal to the tail model signal.
Cutoff:
The Cutoff control is essentially a low pass filter. Adjust to match the tonal quality of
the original signal to the tail model signal.
An example application for using the Tail Model is when you go past the 3 second
mark (at 48kHz) with impulse responses. By enabling tail model you won’t gain much
in CPU savings for the shorter IRs.
Note: Using Tail Model on impulses with an artificial envelope to emulate a decay are
NOT RECOMMENDED. The tail model is designed to work well on impulses that are cut
off at the end of their sampled duration. Applying a tail model to an impulse response
with an artificial decay envelope will not give satisfactory results.