[sdiy] IR Reverb

rsdio at audiobanshee.com rsdio at audiobanshee.com
Wed Feb 21 02:57:21 CET 2018

The Blackfin is rather middle-of-the-road in DSP performance. That’s fine if you need to run a wasteful operating system like Linux and still need decent DSP performance from the same chip. But dedicated IR Reverb hardware really shouldn’t use Linux at all, so the few advantages of the Blackfin are rather moot.

There is a paper from a DSP expert that pits nearly all of the DSP options against each other, and the Blackfin does fall right in the middle.

Folks who haven’t used assembly or DSP really don’t get the difference between a general purpose CPU instruction set, versus a complete DSP design. The ARM chips like the STM that have one or two MAC instructions and a relatively high clock rate are still no competition for a full DSP. ARM with MAC cannot keep up with Blackfin, and even the Blackfin is not as capable as the SHARC or TMS320.

Impulse Responses and Convolution are basically the most challenging audio processing I can think of. You really need to take advantage of the processors that have evolved over decades for exactly this kind of processing. Thankfully, TMS320 and SHARC have libraries so that you don’t actually have to write the hard stuff. It’s almost as quick to develop as on a desktop.

Yes, there are a lot of options, and, yes, you can probably pull off an IR Reverb with any of them. But you’re going to get the most performance out of a full DSP chip rather than a general purpose CPU - even one with a MAC instruction tacked on.

Brian Willoughby

On Feb 18, 2018, at 11:20 AM, Bruno Afonso <bafonso at gmail.com> wrote:
> If you're willing to go into DSP land then you could also look at blackfin, Monome's Aleph uses open source tools for develop it. For STMs, the only shot would be to attempt to use fixed point, not a lot of juice for floating point stuff but like other's mention, it may be a lot of work.. maybe more for as a challenge? :)

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