Ha, I couldn't work out what _isn't_ a good UX about them until you posted this. It's worth noting a couple of extra things about them too, while taking up much less space than a slider they operate in the same way - this often means you can get a lot more range / precision than if you'd tried to fit it in a slider as your touch can slide way outside the bounds of the control itself. The other is that there's a convention in touch-interface audio apps that double tapping the dial will return it to its default state, whatever value that might be. This arguably could be done with a slider, but I've not come across that on any of the apps I use.
Huh, didn’t know about the double-tap, I’ll have to try that.
You’re right about range and precision too. With knobs, the interface creator can fine-tune the precision without it being surprising. A knob that changes oscillator waveforms can have large, comfortable slices between each waveform, while an envelope length can be more fine-grained.
One could build in coarse/fine adjustments based on swipe speed, but that seems a lot harder to get right. I’m still quite hopeful about what VR synths and controls can bring. Synthspace may be the thing that makes me get a VR headset, and if someone ever ports VCV Rack to VR I’ll be there in an instant.
