Dexed FM synthesizer similar to DX7 running on bare metal Raspberry Pi
In this technical retrospective (2022), @rcarmo shares practical architectural lessons learned from running, scaling, or migrating production software under lean constraints.
Core Principles for Independent Builders:
Defaulting to simpler architectures (such as monolithic frameworks, SQLite, or managed VPS) prevents early engineering bankruptcy.
Evaluating true compute and egress costs reveals that high cloud bills can often be slashed by 80%+ through judicious re-platforming.
Code you write at 2 AM as a solo engineer must be easy to debug six months later without complex microservice dependencies.
Community Debate Themes:
HN engineers debated the tradeoffs between cloud convenience and raw server economics, database indexing strategies, and resisting premature architectural complexity.
CATEGORY Frugal Engineering →
HISTORICAL ERA Pandemic Bubble (2020–2022)
COMMUNITY SCORE ★ 176 points
TOTAL DISCUSSIONS 33 comments
Nice! I've just recently started targeting the 64-bit Pi as a plugin platform, and have ported my entire library to it. So that's nearly 300 plugins also for the Pi, but no synths, just audio processors. And I use Dexed to make sounds, so this is right in my wheelhouse. Even have spare Pi 3s kicking around :)
I'm still trying to get Renoise up and running on the new Pi (400), but have already demoed a full Reaper mix with various plugins running that was made on an iMac Pro with no consideration as to CPU load, running just fine on the Pi too. All the sounds were 96k and on the Pi the project was resampled on the fly to 48k, but it played!
Add the right synths (such as Dexed: I like running it at 24 bit as a sound design machine, not just a DX7 imitation) and samples and the Pi is starting to turn into a full-on music workstation. Thrilling!
I would add that running Dexed on a bare metal Pi, means that you don't have to reinvent sound design and can use patches made elsewhere… but then, play them on the discrete unit, through whatever DAC, and then DISTORT them in analog in whatever circuit you devise, or a stompbox. Or simply run it into a ADC, some basic thing, that's not meant to take those high levels: I have a Razer thing that's easy to distort by running into its little mic input.
Overdriving FM with analog distortion gives you intense sounds that you'd struggle to match, purely in the box :) and being able to run a Dexed on a spare Pi makes all this very easy, doesn't it?
Pretty cool. Seems like this project was built on the Microdexed [1] code, which is a port of Dexed to run on a teensy. It uses circle [2] as a bare-metal basis on the pi, which was also used by mt-32pi [3] to run a sample-based synth that can emulate the roland mt-32.
[1] https://codeberg.org/dcoredump/MicroDexed [2] https://github.com/rsta2/circle [3] https://github.com/dwhinham/mt32-pi
Any chance to see it run on different ARM boards other than the RPi? I ask because the RPi audio output is notoriously bad, to the point it requires an external DAC for any decent audio use, while there are many other cheap ARM boards out there with perfectly good internal DACs, and sometimes also very good ADCs.
Usually I have hard to solve ground loop noise issues with my Raspberry Pi based synths when used in combinaton with other synths. So while this is for sure a nice project, with all due respect and kudos, for those really only interested in the DX7 sound, it is probably better to look into the new Volka FM 2.
Nice
I've been building little raspi synths for awhile but they all sit inside Linux because bypassing the os is outside of my dev comfort zone.
But it's obviously the way to go. The dx7 is pretty well tread space, I'd love to see some great granular synths on rpi like the GR-1