[sdiy] Re: granular synthesis

[Czech Martin]

Perhaps I can.

At least I have made a true electronic piece of music with it
(some say "academic electronic music").
This is "no dancefloor" but I can see no reason
why GS could not be used for pop music as well.
The input sample was a German text, somebody explaining
the  basic constituents of sound (spoken by Herbert
Eimert). So this piece has some kind of self reference.
You can her some crazy loops, very much slowed down vowels,
sometimes you would never believe what the original
material was.

Ok, I'm 37 now, so I do not believe in "the next big thing"
business any more. Just to much disappointments.

I think GS was much overestimated when it was fashionable in 1970-1980
or so, of course especially if you read papers of people
that claim to have invented this method, or have done some
contribution. What else can you expect of them?

What does GS really do? Basically it spits out a bunch of
little samples with some kind of envelope arround,
we know this idea from quantum physics in a way,
wave-particles. 

Think of some table in which the audio material resides,
then we need a pointer where to start playback
and another one where to stop. Or start and length,
if you like it more. We need a freq parameter which determines
the velocity (or increment) in which the sample is played back.
And we need to have a modulation of the start entry.
Finally we need a rate parameter, which rules when the
next sample will be played. And some envelope and multiplier
to window the sample when it is played, in order to avoid
clicks & pops.

Of course you can have mutliple tables spitting out
bunches of grains at the same time.

Note that a tape device existed ("Tempophon")
with four rotating audio heads that could mimic
a lot of a GS tool, but of course the start pointer
thing had some difficulties there.
So your notion of a gone haywire tape recorder is not so wrong,
but not complete.


Now, the starting point can be rate=20/s, starting point at zero,
short samples (grains), and grain playback frequency 
same as recording freq. The start pointer should move on 
so that the entire sample is played. WHat we now have
is a representation of the original sample, at normal speed
and pitch. The fact that it is not continously played,
but in little grains, is almost hidden due to overlap
of grains.

Now we can do some alterations. First we can speed up 
playback frequency. The pitch will rise, but the total
sample time will not shorten. Pitch shifting in time 
domain (with all side effects).
Or we can speed up start pointer movement.
Time compression in time domain!.

We can make the grains longer and rate lower,
some kind of strange echo!
We can even reverse start pointer movement,
even stranger echoes!

We can stop the start pointer, time stretching to
infinity.
etc. etc. etc.

So, GS can do something usefull.

Basically a mixture of AM, timestretrch/compression,
pitch shift, echo, flanging.

This sounds like postprocessing.

Of course, you can pick some part of the sample and loop
it very fast with different frequ, that's wave table stuff is,
isn't it? So the borderline between postprocessing
and synthesis (if it exists) is very fluid with such a tool.

The problem is  to grasp, what is behind the parameters of "granny".
I've made a nice write up (in German), because I tend to forget
so fast:
(http://www.zem.de/heft/22_granny.htm).

Once this is settled, you can e.g. use the gesture window to
manipulate some parameters with mouse-joystick
in real time. I mentioned above that using this feature you
can bend things into total disintegration and back.

It takes some time of experiment to get something out of
a somehow complicated machine.

m.c.


-----Original Message-----
From: Glen [mailto:mclilith at charter.net]
Sent: Mittwoch, 16. Juli 2003 12:21
To: Czech Martin; Fdi; synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] Re: granular synthesis


At 05:43 AM 7/16/03 , Czech Martin wrote:
>Ever heard of "granny"?

I have "granny" here at home. I never could get anything very interesting
out of it. What I'd like to find are some recordings that demonstrate the
solid musical value of granular synthesis. So far, all I have heard are the
sort of sounds you would expect from a mangled cassette tape being eaten by
a rogue cassette player. Could this actually be the "next big thing" in
synthesis, as it is sometimes claimed to be? Most of what I've heard
doesn't even sound like synthesis. It sounds like post-processing, albeit
extreme post-processing. 


later,
Glen Berry