[sdiy] MIDIVerb reverse engineering

[Chris H. Park]

Kudos for the decision to GIT the work!

Chris Park
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________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Eric Brombaugh via Synth-diy <synth-diy at synth-diy.org>
Sent: Wednesday, July 16, 2025 4:44 PM
To: Pete Hartman <pete.hartman at gmail.com>; brianw <brianw at audiobanshee.com>
Cc: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: Re: [sdiy] MIDIVerb reverse engineering

There are links to all four Youtube videos in the Github README - just
scroll down. I've also posted the presentation slides which provide a
high-level overview of how the DSP works - look in the 'doc' directory.

Eric

On 7/16/25 1:21 PM, Pete Hartman wrote:
> I'm not sure the disposition of the videos, but I recall Paul describing
> all this discrete logic and the pipeline in them.
>
> Pete
>
> On Wed, Jul 16, 2025 at 3:08 PM brianw <brianw at audiobanshee.com
> <mailto:brianw at audiobanshee.com>> wrote:
>
>     Thank you!
>
>     I believe that it is very worthwhile to preserve knowledge of
>     vintage electronics design.
>
>     I took a quick look at the collection of files, and specifically the
>     schematic. It seems that the "DSP" is actually implemented via
>     discrete logic chips. I also noticed that there is a pipeline which
>     is potentially quite confusing. Do you have a high-level overview of
>     how this "DSP" works?
>
>     I recall looking inside my A.R.T. MultiVerb back when it was new,
>     and it also seemed to have discrete "DSP" controlled by a too-slow-
>     for-digital-audio-sample-rates 8-bit MCU. I've long been curious how
>     that worked.
>
>     Brian Willoughby
>
>
>     On Jul 16, 2025, at 12:35 PM, Eric Brombaugh wrote:
>      > Back in 2021 Paul Schreiber and I reverse engineered the MIDIVerb
>     I and although Paul posted a number of Youtube videos to discuss
>     what we'd learned, we decided at that time to keep the design
>     materials we'd generated from that effort private. Now that Paul is
>     no longer with us I've open-sourced the materials on Github:
>      >
>      > https://github.com/emeb/MIDIVerb_RE <https://github.com/emeb/
>     MIDIVerb_RE>
>      >
>      > This repository includes schematics, presentation slides, source
>     code for the disassembler, emulator and compiler, as well as SPICE
>     and Verilog models of the logic. Anyone at all curious about how
>     this product democratized the world of algorithmic reverb is invited
>     to take a look - it's a fascinating glimpse into 1980's minimal TTL
>     design and a testament to the genius of Alesis founder Keith Barr.
>      >
>      > Eric
>
>
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