The Qweremin
I invented a new instrument: The Qweremin is a qwerty theremin.
Background
In the summer of 2022 I built a C64-based theremin, described and explained here. The theremin, of course, is one of the oldest electronic instruments. Its main drawback—and strength—is that it's incredibly hard to master. The performer has ultimate control over volume and pitch, but it takes months of practice before you can play even a simple scale.
Meanwhile, I've also developed a line of instruments featuring qwerty keyboards, where the keys are laid out as on a Type B chromatic button accordion. The earliest example is the Sixtyforgan, presented in spring 2021, but there's also Qwertuoso, the Commodordion, the Paulimba, and the C=TAR. For these instruments, the main challenge has been how to incorporate phrasing and other forms of musical expression; to move beyond the rudimentary note-on, note-off of an organ.
The Qweremin represents the unification of these two worlds. On the one hand (pun intended) you have ultimate control over volume and expression, and on the other you can play quick melodies with large jumps, and even chords. It is my most expressive 8-bit instrument yet.
The volume control
As mentioned in the presentation video at the top of this page, the SID chip only offers a crude 4-bit master volume control. For greater precision you have to work with the envelope generators, but those always produce ADSR curves. What I did in the original theremin project was to hack together a feedback loop that would continuously monitor the current output level from one of the envelope generators: When the present level was lower than the desired volume, I would trigger a new note to enter the attack phase, and when the level was too high, I would release the note. In this way I could make the envelope generator hover around any desired volume.
To make this work, I had to set the attack and release rates carefully. Too fast, and the volume would audibly oscillate back and forth between two levels. Too slow, and the volume changes would lag far behind the hand movements. I thought I had found a sweet spot, but it turned out I was being naïve.
In 2023 I ran into Bass Cadet, a thereminist with a C64 background, at the Revision demo party. She had seen my video and was enthusiastic about some day being able to get her hands on (or near, technically speaking) a C64 theremin. It turned out that we were both planning to attend another party, X, later that year. And since I was going to bring my C64 anyway, it was a simple matter to throw the spoon and clamp into my luggage as well.
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