I’ve been drawn lately between trying to build a function generator with op-amps and using an ATTiny or Beetle or something. After you get past putting a voltage clamp on a trigger and using 10v on a voltage divided digital potentiometer are there good reasons not to use microcontrollers? I feel like I’m resisting because it’s in some way “cheating” to use that system, but synths from the CS-80 on have all utilized them so it’s probably silly of me.
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Who’s to say what’s right for you other than you? Practically speaking there are things that are a lot harder or effectively impossible in hardware that a microcontroller makes easy. On the other hand I’m drawn to the “as simple as possible” philosophy and am perplexed sometimes by use of a microcontroller when it seems as if it’s not needed. And on a personal level, I can program but find programming microcontrollers kind of tedious, while on the other hand my hardware design skills are limited which means I should do more of that as a learning exercise.
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I think there’s a little snobbery about analogue, but perhaps mainly that’s among amateurs and hobbyists.
I’m interested in putting things together in different ways to see what the result sounds like. I can be using patch cords or unit generators. The latter is much quicker and far less time-consuming and costly. Both have a place in modular synthesis, in my opinion.
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Not cheating at all. I made a module from a broken micro cassette recorder for noise,
A BBC micro sequencer and a degausser I used as a filter.
My most prized accomplishment as a contract program manager was my JFDI accreditation.
(JFDI. Just Do It!)
Values are values, waves are waves. Have fun and carry on. I like the idea of using an attiny. Lots of fun MIDI and signal ideas. Brent Edstrom’s book Arduino for musicians is a brilliant resource. Enjoy
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I think I am going to second the notion of it coming down to snobbery. Personally I like the way analog sounds, with all its non-deterministic weirdness, but there is nothing wrong with digital. There are some kick ass digital sound modules out there and they sound all kinds of awesome. I have a Soulsby Oscitron (which I got Paul Soulsby to sign when I met him) in my euro which is an unashamedly digital module for all my modular chiptune-y needs and I love it, but equally wouldn’t part with my Moog Sub Phatty because of the amazing analog sounds it produces.
I think only you can determine whether its cheating, mind you. If you set out to build an all analog monster synth, building some digital oscillators for it might be sacrilege, then again they might be performing tasks that you genuinely can’t do with an analog module and in your mind be appropriate. I think it just boils down to what you are trying to do and what makes you feel good/sounds good and ignore the naysayers.
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Things are good because they are good, not because they are difficult. 
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and what about digitally controlled analog oscillators? are they a halfbreed? like a step child? and I really like the idea of a on the fly drawable wavetable oscillator try that with analog… and since I’m the NEWB 'round these parts, its all difficult until you get the hang of it… 
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Drawable wavetable or using some slider pots as inputs are thing I’m trying to work towards. It’s a cool idea. I’m all about hybrids and using what works. My end goal is making music though so my utility function may differ from yours.
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I can see one of those old high persistence cathode ray tube displays (the kind that was used primarily in RADAR) taking a trace drawn with a light pen. A simple Williams Tube-style delay-refresh system keeps the trace on screen while it generates a varying voltage as it’s scanned from left to right.
But arguably once you’re using Williams Tube technology you’re digitising a signal, so it’s not strictly analogue.
On the other hand, triggers and gates are inherently digital, even if they look like analogue signals to the naïve.
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do we have a LMNC suggestion box? because that, sounds like an amazing idea!
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You know, I have one of these sitting up in the project closet from a quadrophonia experiment that kind of petered out:
I’m tempted to see if I can work out the code now.
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High persistence phosphor is a very 1940s idea.
Speaking for myself I’m not entirely sure I’d get much out of a hand-drawn wave. It might be more intuitive for amplitude envelopes because at the macro scale we can perceive such an envelope in a graphic way that escapes us at the individual wave level.
My son plugged my oscilloscope into his guitar pre-amp the other day, and the result was a very pretty and regular wave, something like a lop-sided sine. If I wanted to reproduce such a wave, though, harmonic analysis would make more sense to me. Like those draw bars on a Hammond.
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As a general update, I’m still using Supercollider for what little spare time I have available for audio synthesis. I’m also investigating less expensive, less powerful alternatives to Bela for use in completed modules.
Axoloti shows promise, but the finished systems appear to be bottlenecked by the single producer’s painstaking production techniques. Since he’s now working on Axoloti 2, I don’t think we’re likely to see a glut of Axoloti. There is no kit alternative, to the best of my knowledge.
Teensy, on the other hand, has comparable physical capabilities and is supported by the brilliant Faust DSP system. The latest version of the hardware, Teensy 4.0, has no onboard DAC, but the price is very low, at $19.95 for an ARM Cortex-M7 processor at 600 MHz. There is also an inexpensive and excellent audio shield, $13.75 for 16 bit I2S audio, 44.1 kHz sample rate.
Reportedly the Teensy can produce four-channel audio by using two audio shields, though some soldering is required for that. The default configuration is two audio channels with one audio shield.
At this price, the cost of a reprogrammable digital module kit is competitive with analogue kits (which may or may not make it a viable alternative depending on your reason for choosing a traditional modular format.) You still need to add op amps and capacitors and jacks and switches and a front panel, but the reprogrammability is a very attractive characteristic. If you don’t like the sound, you can tweak the Faust or C++ (or whatever you’re using), upload it to the board and then carry on with your session.
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ElectroSmith just launched a Kickstarter campaign for the Daisy which is essentially a Teensy with builtin audio interface.
It will support Arduino, Pure Data, FAUST, MAX/MSP Gen~, MicroPython and their own C++ audio/DSP library.
The (semi)finished products are expensive, but the basic board is a pretty good deal at $29.
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At this rate, it won’t be long before you can run ScSynth or a similarly capable OSC server on an inexpensive board. Systems like Bela are already there (but the cost is around £100 all-in for the Bela Mini mounted on a PocketBeagle.)
A thing I notice here is that the sophisticated software platforms like Faust are revolutionising what a bare metal microcontroller can do. Bela runs on a traditional SoC running Linux, which means it has to use a real-time exec to pre-empt the traditional and slow operating system processing stack. That has great advantages (you can run the editing environment on the Bela platform itself, for instance, and support for external hardware is as broad as Linux can make it) but the bare-metal systems are catching up. Teensy 4.0 is nearly in the same raw power range as the Raspberry Pi Zero, but it has Arduino IDE support through Teensyduino and it isn’t burdened with the typical OS tasks of a general purpose operating system.
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Oh I just noticed I still have that Korg NanoKontrol2 looking at me accusingly from a shelf. This is a cute little device that gives you an array of twenty-four buttons, eight knobs and eight sliders, plus a handy transport control section. Using Korg’s free editor (on Windows) you can edit exactly what kind of MIDI event happens when you adjust any of these controls. You can also enable external control of the LEDs on the device.
Now I’m not going to say that this kind of arrangement would be much use in a performance or a recorded live piece (I agree with Sam that big knobs and big jacks work best in real life) but it does provide a satisfactory physical alternative to a crowded mouse or touch screen interface. There are for instance several SuperCollider libraries that permit you to link your code to the controller, and the procedure involved is so simple that it can be applied to just about any MIDI-capable digital system, whether it’s coded in C/C++ or any other programming language.
I’ll certainly be using this device. You can buy them on eBay quite cheaply. The going rate for a new one is around £45 while unused second hand ones are going for as little as £32.
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Not quite sire where to put this so feel free to move if there’s a more appropriate thread.
Lovely new update video on the teensy synth from our old pal Dave at notes and volts.
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