Peter Nyboer

I have been working on a demo of additive synthesis for a class. I wanted to show the construction of tri, square, and sawtooth waves as mere sums of harmonics of sine waves. So i made a poly with a simple patch that mutes even harmonics for triangle and square, and adjusts the amplitudes (1/harm#^2 for tri, 1/harm# for sq. and saw) as necessary. The thing is, the oscilliscope doesn't show a waveform that looks anything like it is supposed to (though the spectral content looks about right). 

So I guess I need to make some sort of phase adjustment so the picture looks right... 

How can I show the class that science is TRUE? :)

http://www.yowstar.com/share/additive.zip

and, in the spirit of things, a Wendy Carlos instructional sample:

http://www.yowstar.com/share/sinesqorwhite.mp3

on a related note, why aren't the anti-aliased oscillators normalized from -1 to 1?

I have been working on a demo of additive synthesis for a class.  I wanted to show the construction of tri, square, and sawtooth waves as mere sums of harmonics of sine waves. So i made a poly with a simple patch that mutes even harmonics for triangle and square, and adjusts the amplitudes (1/harm#^2 for tri, 1/harm# for sq. and saw) as necessary.  The thing is, the oscilliscope doesn't show a waveform that looks anything like it is supposed to (though the spectral content looks about right).  
So I guess I need to make some sort of phase adjustment so the picture looks right...  
How can I show the class that science is TRUE? :)

here's my patches: http://www.yowstar.com/share/additive.zip

and, in the spirit of things, a Wendy Carlos instructional sample:
http://www.yowstar.com/share/sinesqorwhite.mp3

on a related note, why aren't the anti-aliased oscillators normalized from -1 to 1?


additive-sythesis-theoretical-failures

> I have been working on a demo of additive synthesis for a class. I wanted to show the construction of tri, square, and sawtooth waves as mere sums of harmonics of sine waves. So i made a poly with a simple patch that mutes even harmonics for triangle and square, and adjusts the amplitudes (1/harm#^2 for tri, 1/harm# for sq. and saw) as necessary. The thing is, the oscilliscope doesn't show a waveform that looks anything like it is supposed to (though the spectral content looks about right).

Looks okay to me, mate - you just need to scale the waveform down

some.. Remember that unless you set the frequency high you're only

getting a small fraction of the necessary partials.

> on a related note, why aren't the anti-aliased oscillators normalized from -1 to 1?

It's not possible to normalize them exactly because the peak value

can't be predicted. Something seemed wrong about scaling to the same

amplitude as cycle~ and having the signal "clip" above 1, so I went

with the half amplitude instead... like phasor, I guess.

> I have been working on a demo of additive synthesis for a class.  I wanted to show the construction of tri, square, and sawtooth waves as mere sums of harmonics of sine waves. So i made a poly with a simple patch that mutes even harmonics for triangle and square, and adjusts the amplitudes (1/harm#^2 for tri, 1/harm# for sq. and saw) as necessary.  The thing is, the oscilliscope doesn't show a waveform that looks anything like it is supposed to (though the spectral content looks about right).

Looks okay to me, mate - you just need to scale the waveform down
some..  Remember that unless you set the frequency high you're only
getting a small fraction of the necessary partials.

It's not possible to normalize them exactly because the peak value
can't be predicted.  Something seemed wrong about scaling to the same
amplitude as cycle~ and having the signal "clip" above 1, so I went
with the half amplitude instead... like phasor, I guess.

additive sythesis theoretical failures...