Teensy boards are really slick, they're great small ARM boards with a lot of power. The audio filters and such here look great.

Huh, I was additionally impressed that they could fit DSP functions on an 8bit AtMega microcontroller, but I see that's just the Teensy 2.0. Didn't know the 3.0 was ARM Cortex-M4 based! There's definitely more computation room there.

Yes, but it appears from http://www.freescale.com/webapp/sps/site/taxonomy.jsp?code=K...

that the MK20DX chip used on the Teensy 3.0 doesn't have the FPU and only clocks to 48 MHz. (3.1 clocks to 72 Mhz).

A bunch of us have been having a blast for the least two years with the STM32F4 which contains the FPU and clocks to 168 MHz. See http://reddit.com/r/stm32f4

Nevertheless, this web user interface by PJRC is quite spiffy. I can see synthesizer design moving ever-so-slowly in this direction.

I have an stm32f4-discovery board for a while that I've been meaning to play with as soon as I can make some time. Thanks for highlighting that subreddit!

This seems like it would be a great way to make your own guitar effects pedals.