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Re: on octave dividing
Title: Re: on octave dividing
Andy simultaneously explains what I did and probably clearer,
but:
Octave pedals.
analog - uses a simple divider circuit, so produces a synth sound
unrelated
to the timbre of the input. (although some have an output which tracks
the
input in volume)
Not in general. Two types of analog circuits:
- Either the effect sound is taken from a rectangular wave
whiches volume is adapted to the input volume, and the ouput timbre is
not related to the input timbre (Polysubbass)
- or the phase of the input signal is alternated at each wave
end, which is easier since the volume is given by the input signal.
The timbre is altered drastically by the phase turn but it still
depends on the input signal. (Boss, Yamaha, Mutron...)
A sine wave input turns the following
output:
...
....
. .
.
.
. .
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.
. .
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.
. .
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.
.
.
.
. .
. .
. .
.
. . .
.
. . .
.
. . .
...
...
A different input into a different output accordingly. Depending
on at which zero crossing you flip the phase, a sawtooth turns either
into a triangle or:
.
.
.
.
..
.. ..
..
. . .
. . . .
.
. . .
. . . .
.
. . .
.
. . .
.
. .
. . -- >
. . .
. .
. .
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.
. . . .
. . .
. .
. . .
. .
.
. .
. . .
.
..
.
.. ..
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.
. .
You can also flip at the maximum (or minimum) of the wave
(Yamaha) which results into other waveforms as you may draw them
yourself now :-)
Rectangle results in rectangle
These have a very fast response. They
don't do chords. May
have very irregular
tracking.
By far the smartest tracking is done by Mutron: there is a kind
of a frequency memory, so when the input signal fades and becomes
impossible to track, the Mutron Octaver goes on using the same
frequency for the said phase alternation.
digital - complex process, so you always get a delay. Signal output
attempts
to sound like the input slowed down. Will work with chords, but will
be
optimised for either single notes or chords. Always tracks, but
signal may
be broken up.
right, I forgot to mention the delay in my text.
In the Polysubbass, I fade in slightly delayed to avoid the
octavation of the beginn of the attack which is not low anyway. The
clean original attack of the string is the most acurate possible. Bass
establishes slowly by its nature.
--
--->
http://Matthias.Grob.org
