[sdiy] Quality reverb on STM32's?

[Tom Wiltshire]

+1 agree.

The FV-1 chip pulls off some decent reverb algorithms, with only 1 second of delay memory at 32KHz. The secret in that case is Keith Barr’s inside track knowledge of “good reverb for cheap” and how to get the best out of algorithms by using all pass filters and so forth to “smear” the reverb. As Eric says, a lot of it is in the “tuning”.
In terms of MHz, the FV-1 uses 128 cycles per sample, so that’s 4MHz - yeah, seriously; you can do decent reverb at 4MHz. At least, Keith Barr could and the rest of us had better catch up! ;)

Example from Mick on DIYStompboxes:

https://www.youtube.com/watch?v=0k69GtDoin4

Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================

> On 13 Apr 2018, at 20:38, Eric Brombaugh <ebrombaugh1 at cox.net> wrote:
> 
> It really depends on your definition of "quality". I've been able to build reverbs on STM32F4 and STM32F7 that sound like reverb but probably wouldn't have the cognoscenti turning cartwheels, but then I was just spitballing to see if it'd work and didn't spend a lot of effort on tuning them up.
> 
> It all comes down to what kind of compromises you're willing to make - choice of algorithms, tolerance for short RT60, metallic / resonant artifacts, etc. Tuning up a reverb that sounds great is definitely an art, not science and the folks who do that will spend a long time to get it just right.
> 
> For reference, the Spin FV-1 reverb chip has just 32k samples (using their crazy reduced-precision floating point format) of on-chip memory that's used for delay buffers and allpass filters. Those reverbs are passable if not fantastic. I was able to port one of their demo algorithms to an STM32F405 using only on-chip memory and it worked fine. With off-chip memory I'm sure you could do even better.
> 
> Eric
> 
> On 04/13/2018 12:25 PM, KD KD wrote:
>> So when we the unwashed public finally have access to 32bit and SAI/I2S
>> with large on board SRAM's i wonder how many Mhz and Kbytes do one
>> need to make "quality reverb" on STM32? I'm thinking of how much is
>> "enough" to make quality reverb with the known principles excluding the
>> large memory sampled ones?
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