World: r3wp

As you add together a larger number of waves, you will find the maximum 
amplitude is typically much less than the total of all the wave amplitudes. 
It might be easier to generate all the samples of the complex wave 
(using decimal!/float), keeping track of the maximum value, then 
scaling it to 8 or 16 bit integers afterwards. It would be nice to 
have a precise mathematical way of calculating the maximum peak values 
in advance, though...

yes - that would be nice.  Ill have a hunt about see what i can find. 
 I know a couple of sound engineers who might know

It makes me think of something called Fourier Transformations:
http://en.wikipedia.org/wiki/Fourier_transform

yes - they are good for decomposing waves.  very math/processor intensive 
though

hey guys,  I have somewhere an FFT implementation in Rebol, interested 
?

Steeve, what did you use it for? Just experimenting?

it shows frenquencies for a sample, but i don't remember how i did 
that, i can post the demo

would be interesting to see one :)  My next project is to decompose 
complex waves into sheet music :)

FFT = Fast fourier transform

of course - thats about a month away at the rate of my current project 
:)

Hoho!

ok i upload the old demo

*** UPLOAD at http://sites.google.com/site/rebolish/Home
(see FFT.R at the end of the page)

you have to load a wav sample

Wow - first use of CP (alias of COPY) I ever saw. I override CP to 
be a unixiod file copy function.

long wave file .... crunch crunch...

it's an old script Anton

I see a little graph :)

yep, it show a graph with some frequencies, don't remember why...

:)

I've got an old script which uses FMOD library to show a spectrum 
window in rebol while a sound is playing. It's a Windows DLL but 
it works in wine.

 do-thru http://anton.wildit.net.au/rebol/audio/fmod/play-rebol-sound.r

Icarii, calculate RMS of the sound.

Anton:
** Script Error: cv has no value
** Where: do-parse
** Near: cv mold type-converter/c-to-rebol-map

Steeve, thanks for the FFT, I'm really interested. I had only DFT 
running for my modular synth. And maybe iFFT also, I don't remember, 
I hope the sources are still somewhere in deeps of the Internets.

Anton, you asked why i had an FFT implementation...

Because, i made some tests to extract frequencies from wav sounds, 
to be able to play sounds on an old 8bit sound chip.
And also, i wanted to use FFT to make an image compressor.
Geez, so much projects vanished...

Oldes, thanks. Do this

 load-thru/update http://anton.wildit.net.au/rebol/os/make-external-library-interface.r
then try again.

new version of synth almost ready - added an oscilloscope so i can 
see where my complex waves are not behaving .. lol

just realized that altme (probably rebol itself..) fucks up my system 
volume  :-(

when it pings, my sound driver's "WAVE" slider resets to 33%   >:-(

has anyone noticed this side-effect with rebol before?

it should just set its own volumn, not the system's wave volume..

Maxim, RAMBO #4239

ah thanks.