Bela, where software meets modular hardware

DIY STUFF
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A member of my family studied at Queen Mary University of London (QMUL) who are really brilliant; my relative got a First and won some kind of prize for being a genius, so obviously they are very perceptive people! So it was great to see the other day that they (QMUL) are active in open source hardware for music.

It’s not the 1960s any more so the best way to work on analysis of sound, algorithmic composition and whatnot, and a whole slew of great fields of sonic study, is to use computers.

Enter Bela. It’s a completely open source hardware platform that will convert Pure Data scripts into C, compile them and run them at blinding speed, achieving latency around 1ms (in other words, you won’t notice the delay) for digital signals, and even better for analogue signals.

A couple of years ago these maniacs went and built a Bela into a Eurorack module, and have sold it in small quantities ever since. You can program this module, with its multiple jacks, buttons, LEDs and potentiometers, to do anything you’d like. It’s called Salt.

The wonderful thing about this is not that it exists (the VCS3 existed but I’ll never have a chance to play one) but that it’s completely open source hardware, completely open source software, and it’s relatively inexpensive to build.

You can program this module to do anything you want (VCF, VCO, LFO, sequencer, mixer?) and then disconnect your laptop and walk away. It’s less expensive to build, DIY, than most ready made Eurorack modules.

If you’ve ever run any digital synthesiser software, from CSound to SuperCollider, you’ll be able to imagine how wonderful it would be if you could get that virtual synthesiser to think quickly enough to be able to react to controllers and other signals in real time.

I think this may be a revolutionary moment. We’ve reached a point where it costs less to build a few programmable modules and then make them do whatever you want, than to spend the same money on modular hardware that will only ever do what is was originally wired to do.

We did this. Humans did it. We made Wikipedia, we made Linux (and BSD), We made Beaglebone Black. Now anybody who is prepared to put in the time and energy can build any noise machine they want.

(Exits muttering “if only solving the climate crisis were so simple.”)

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If only Salt wasn’t 395 uhh… not us currency… lol (idk how to make that symbol… lol)

Friggin cool tho -

I have been thinking about getting into the Axoloti Core and such.
Jonas Bers made an Axo to Eurorack Conversion PCB that is really neat and I’ll be building soon!
Axo is kinda like MAX/MSP.

This Bela sounds similar!

Have you ever seen the ArdCore module?

I love the idea of a “universal” module!

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Well that’s the thing. If you bought a Salt module (and if you did you’d be mad not to buy the Salt+ extension module) it would cost you nearly £600. But the hardware is available off the shelf, it’s completely documented, and anybody is allowed to build it.

We take it for granted that the CEM3340, the Electric Druid chips and whatnot, even the humble 555 timer, all exist and can be exploited by anybody with a soldering iron. That’s somebody else’s work, but now anybody can use it.

Most of us know that in the digital medium a similar principle applies. If I decide to build a clone of Bela’s Salt module I’ll be sure to document the process. It’s all public domain. I’ll be sure to let everybody know if the DIY cost gets anywhere near the prices charged for completed, tested and calibrated hardware. As far as I can tell, anybody seriously interested in modular synthesis can just buy a BBB and a Bela cape for about £110 and put the rest of it together on stripboard and bits from their parts bin.

For a circuit that can be programmed to do whatever you need here and now, whenever you need it, that’s amazing value.

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Do not get me wrong, I see the value in it, Very much so.

Just in that spot in life where DIY is the only cost effective way to make modular chaos.
Life is not super friendly to everyone haha

600 to me is a months rent. :slight_smile:

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Sounds roughly like a Disting. Is it comparable?

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I get what you say. There’s no way I could ever afford £395 for a module. But £110 for a music computer that I can one day install behind a Kosmo front panel isa bargain. Pressing one of the buttons on the panel will completely change the way it behaves, or I could touch a control on the screen of my smartphone to tweak a modulation parameter.

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I looked at this overview of Disting 4:

https://www.expert-sleepers.co.uk/disting.html

That looks like a really inexpensive but incredibly useful module, famed for its chameleon-like ability to change its function. However, that is a PIC chip programmed by an expert, like a dainty pebble among other modules. Bela Salt, to extend a simile from Iain Banks arguably greatest culture novel, is a fucking rockslide.

You can write a Pd script, feed it to Heavy (the script compiler) and it comes out as a C/C++ program, some of which will run at a higher priority than the fully functioning operating system that hosts it. Meanwhile the Pic controller will just do whatever it does. Both are impressive. One of them is running on a ridiculously powerful computer with masses of power to spare.

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Well now I need to check out Disting lol

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If I remember right, the Disting is open source C. They have a repo here. I’m not sure about compiling to the correct hex format from, say, Xcode though.

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Fuck, this is the big brain thread. This sounds almost too good to be true holy shit.

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You should look into the Teensy audio adapter and audio library, they provides very similar functionality.

It looks easy to program and they have a detailed tutorial
https://www.pjrc.com/store/audio_tutorial_kit.html

Nuts & Volts also did a nice project with it.

The Teensy hardware is quite cheap and the new Teensy 4.0 has a lot more horsepower than what was used for the tutorial so it opens a lot of posibilities.

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To produce hex format code for Disting from that source you only need the x32 cross-compiler toolchain.

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I do think Teensy and Disting sound like really powerful devices.

What really seems remarkable to me, as a software guy, is that Bela is a recognizable general purpose computer that just happens to be able to handle interactions in realtime. I can write software for a top of the range ThinkPad to play a note when it gets a message from a MIDI controller, but there is always a very slight but perceptible delay, which is what we call latency.

That’s what makes microcontrollers like Teensy and PIC (and AVR/Arduino, which is my personal favourite at the moment) so great. You program them to do one task well, and they excel at it if you first select a microcontroller that is capable of the task. They’re dainty pebbles, as I said in an earlier post here. But in the story of David and Goliath we usually picture the giant being stuck by a stone David, the young shepherd boy, would have been capable of picking up and hurling with the small sling he carried to defend his flock from wolves. A well-aimed stone can do the job.

I’m looking forward to seeing what Bela can do (you can build a version of Bela with “only” 500 MB RAM for less than £100 if you go with their version for the PocketBeagle.) It seems to be a rockslide, to repeat the colourful metaphor I borrowed in an earlier post.

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I’m now quite interested in Teensy 4.0 with audio cape (or whatever) as a potential universal module format. I could just wire it up with pots and jacks, and then it’s a computer, and I’ve spent nearly fifty years learning how to talk to computers. I just need to write a program telling it how I expect it to respond to me.

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I have one ! Amazing utility module, over 80 configurations!
I intend to buy several more in the future, almost future proof! :+1: :sunglasses:

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