[LAU] Progressive Quantisation

Folderol folderol at ukfsn.org
Tue Aug 21 17:01:16 EDT 2007

I posted my thoughts on this over a year ago and was a bit disappointed
at the lack of interest. Maybe you were all deeply engrossed in other
projects so I've posted it again!

Well I don't know if this term actually exists or if I've just invented

This is an idea I've thought about for quite some time, years in fact,
but don't have the programming ability to try to put it into practice.
I'd be very interested in other people's thoughts on it.

Preamble over :)

All the quantisation systems I've seen so far only work if the music
has reasonably constant timing, and then produces much too rigid a
structure for my tastes.

I usually record live work without a metronome as these always inhibit
me. However I find that in a very long piece, I sometimes gradually
speed up or slow down. This is often only noticable if you go back to
the start of a piece and replay it immediately it has finished. If
'standard' quantisation is applied to this then the results can be
quite grotesque as notes progressivley fall outside the quantisation
capture range and get placed into the wrong positions.

What I would like to see is quantisation algorythm the detects trends
rather than absolute values, then progressively applies small
corrections to keep overall timing correct. (it would of course have to
operate over all tracks simultaneously).

For example, the musician could put markers on notes in, say, an
accompaniment section, that aught to fall on the first beat of each
bar. The quantisation would then stretch or shrink the time positions
so most of these fit. I say 'most' as it is the trend we are
controlling not specific notes. Intervening notes of ALL tracks are
then adjusted a proportionate amount. Later bars can then be
interpolated and occasional bars that don't actually have a note on the
first beat will still be adjusted based on averaging. Deliberate note
delays, syncopation etc. would then be perfectly preserved and the
music would retain its liveliness.

Having the musician place these markers rather than some automatic
system, means that not only are the correct notes used as a reference,
but the music can be brought into line even if it initially has
absolutely no relationship with the bar lines in the sequencer (this
happens to me a lot when I try to record live). The quantisation system
would match marked notes against 'real' bar lines. Overall timing can
then of course be adjusted by altering the beat rate.

This whole idea could then be turned on it's head. I find it VERY hard
to get several tracks to slow down at the end of a piece and stay
'together'. This quantisation system could do just this by having
'target' time/beat rates at the start and end of the section that is to
be slowed (or speeded up). Once again, natural variations would be
preserved and only the overal trend would be adjusted.

Will J Godfrey

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