Does anybody have any bright ideas how we might create a shepard tone in Pd?

I made a real basic one in protools but am doing my best to run in the opposite direction of said program. You can even just use a plugin, but seeing as that is boring, I'd appreciate any input.

Here's a link for a shepard tone refresher: http://en.wikipedia.org/wiki/Shepard_tone

Have a look at the audio examples in the help browser. You'll find a shepard tone generator (D9.shepard.tone.pd).

look up a track called 'eternal return' by 'ubar tmar'. it's psy trance with guitar riffs at its very worst, but has made good use of the shepard tone effect.

edit: here it is. don't say i didn't warn you about the psy trance and guitar riffs:

edit2: doesn't kick in until about the 5 minute mark.

Thanks. Yeah it was also used in the Dark Knight when Batman zips around on his uber bike. Sounds electric and always accelerating, kind of neat.

From Wikipedia:

Risset has also created a similar effect with rhythm in which tempo seems to increase or decrease endlessly.

I feel like I've just seen the monolith.

Someone created a SuperCollider implementation. Check out the demo.

ouch.