Harmonics question

[oncken at umr.edu]

I guess this isnt really DIY, but with all the talk of harminics, 
additive synthesis, ect.,  its close enough to pass.  I hope someone out 
there will appreciate this.  

If you wanna play with additive synthesis and harmonics, get yourself an 
amiga500 and a copy of RGS... it lets you draw pictures of sound with 
brushes, (lines, dots, harminics, formants, and lots of other stuff) 
on the screen and the amiga spits out (I think..) up to 255 sine waves 
corresponding to the pixel's vertical placement with an amplitude 
corresponding to the pixel's color.  Placement in time is controlled by 
horizontal position.  It can synthesize in real time...changes you make 
it the picture on the screen are almost immediately rendered as sound.  
For example, by erasing a horizontal strip, you are in effect bandpass 
filtering the sound with a "perfect" filter... and the change is audible 
almost immediately.  

You can also set it to send midi messages for the loudest 16 sines, 
allowing you to draw midi notes on the screen an have any synth play 
them.  The coolest thing is that you can sample a sound, get it into 
RGS, and then 'play' that sound with another synth via midi... you could 
sample a cat's meow, or a voice, or whatever and have a synth play back 
the loudest 16 partials of the sample, giving you a cheap, low-fi method 
of resynthesis.  Neat huh?  Make your synths talk.  :)

I haven't found another program like this.  I've been playing with this 
thing for about a year and have only begun to scratch the surface of its 
capabilities...  Its hard to make familiar sounds from scratch, just by 
building up sines, but its good for noisemaking if for nothing else.  
Its taught me alot about how sound works.  A great way to get really 
unique sounds for very cheap.  

Anyway, check it out, just please keep it a secret... A friend of mine 
GAVE me my amiga for free, he found it at a yard sale for $10.  I dont 
want to start seeing "vintage" amigas for $400 anytime soon.  

Christian Oncken
oncken at umr.edu


ps.. you can do wavesequencing with octamed3.0. Draw the single cycle 
waveforms on the screen, make a bunch of waves and seqecuence them 
with different durations, playback rates, and amplitudes to make a 
sound... take that sound and sequence it at different pitches into a 
pattern... then loop the pattern, go back and redraw the single cycle 
waves while its playing and the sound will change in real time.  Nothing 
else I know of can do this.  (so keep it quiet)  :)  




> I wrote a program in VB5 that has sliders for 9 sine waves (phase and
> amplitude)  The program displays graphically the waveform that would
> result from combining those 9 sine waves.  The sinewave frequencies
> are set at 1F, 2F, 3F, 4F ... 9F to comply with Fourier.
> 
> It's really very cute and shows what happens in additive synthesis.
> It gets very close to a square wave when all odd waves are used at the
> correct amplitudes.
> 
> -- Scott Gravenhorst
> -- FatMan Site: www.teklab.com/~chordman
>