[music-dsp] Open Source DSP Analog Simulation Synth

[Eric Brombaugh]

Rob Belcham wrote:
> The blackfin 'Stamp' board is pretty pokey and has a good feature set, 
> although no audio i/o. I think there are daughter boards you can get to 
> expand it. There's a version of uCLinux (i.e open source tools & 
> drivers) available for it and a pretty good blackfin community forum at 
> www.blackfin.org. Digikey are selling them for $215. The blackfin is no 
> good if you want to do floating point ops, but it's fine for integer / 
> fractional 32 bit maths.

One platform I've been looking at seriously is the TI BeagleBoard. For 
$149 from Digi-Key you get an OMAP SoC (600MHz ARM processor, DSP 
co-processor, 3D graphics accelerator), 256MB DRAM, 256MB NAND Flash, 
DVI-D, raw LCD & S-Video output, two USB2.0 ports, SD Flash and stereo 
audio I/O. There are several flavors of full Linux running on this 
hardware today and heavy development underway to integrate the extra 
OMAP features.

All software development can be done with open-source or free tools (the 
C compiler for the on-chip DSP is closed source but freely available and 
runs under x86 Linux) and it's even possible to do native development on 
the Beagle itself. Audio software from the OS community (ALSA, JACK, 
LADSPA, etc) is reputed to port without too much difficulty and a 
standardized DSP interface framework is also working.

There's a 28-pin expansion connector with UART, SPI, I2C & GPIO that's 
accessible through the Linux kernel. Several hardware developers out 
there are already building daughter cards for it which allow DIY 
development.

This could be the heart of a powerful soft-synth based entirely on 
open-source software. With suitable tuning it can boot to a useable 
state from SD flash in just a few seconds and be running powerful 
multiprocessing soft synths. Add some UI hardware (knobs, buttons, 
displays) via the expansion connector and it could be usable in live 
situations as well.

Eric