knobt-over-fest

Back home from Knobcon, and back into the real world where I have to work and stuff.

On Sunday morning I dipped back into the exhibition hall and bought the Starling Via Scanner. There’s a lot of potential for reshaping both sound and modulation signals and I look forward to discovering what it can do. Then I mostly waited for Dr. John Chowning’s talk.

Dr. Chowning is 85, and his speaking voice sounds remarkably like Johnny Cash’s “Hurt” cover. Between the keynote speech at the banquet and Sunday’s talk, he described the discovery (not invention, he convinced us) of FM synthesis.

Today it seems as if “discovering” FM would simply be a matter of plugging an oscillator into another oscillator’s pitch input. But at the time, voltage controlled analog synthesizers were new and rare, and Dr. Chowning was working in the digital domain. Not in real time, but with punch cards, no buffers to speak of because memory was shockingly expensive, no digital filters, and even a DAC was an exotic piece of custom equipment.

He was a drummer who read a paper by Max Matthews about the potential of computers to make music, and decided right then that he wanted to make music “from the inside out.” He learned to code, and picked up the engineering and math mostly by osmosis and asking a lot of questions.

He was investigating the perception of sound in space — how we know the difference between a quiet close sound and a loud distant sound, how we identify individual instruments and voices in a group — and started experimenting with vibrato. He found that extreme vibrato rates shifted from a perception of pitch variation to a timbral change instead, and explored how changing only the intensity and relative frequency led to very different spectral results. FM was already in use for radios, at megahertz carrier frequencies rather than audible ones, and he found that some of the mathematical laws applied just the same, with very different implications.

In his talk he frequently showed spectral graphs of the effects of FM. FM creates sidebands around the original frequency, with particular spacing and phase characteristics, which can cancel or enhance each other when they reflect around 0Hz or the Nyquist frequency. (Band limiting in FM is just a matter of reducing the FM index as frequencies increase — something that Yamaha loved about it, because digital filters were really poor at the time.) FM can also be used in formant synthesis, which isn’t a common technique for some reason, and which definitely involves thinking in the frequency domain rather than about waveforms or vague “shaping”. It occurred to me that I almost never use spectral analysis unless working with EQ or a filter, and it’s a tool that could tell me a lot about waveshaping and FM. That was my personal moment of insight from the talk.

The concerns of FM in the purely digital domain are very different from modular. It is, by default, linear TZFM — or perhaps phase modulation as Yamaha implemented it in the famous DX7. Dr. Chowning pointed out that he didn’t work on the DX7 at all, but it was the effort of Yamaha engineers overcoming the technical challenges of the day and pushing the frontiers of digital audio.


Since I couldn’t get them at Knobcon, this morning I’ve ordered a replacement for my missing power cable as well as an Expert Sleepers ES-3/ES-6 pair. From there I’ll figure out if any other utilities would help or if they can be handed off to Bitwig.

There’s a phase of experimentation and learning to go through with this new setup, but I am thinking about the next album. Running through my head are some of the ideas presented in Music Beyond Airports: Appraising Ambient Music and the realization that my music is often about scenes. Places real, imagined, dreamed or remembered, their weather and activity at that particular moment, and the feelings associated with it. Sometimes the music creates the scenes, but sometimes I draw them from experiences. I have a few such experiences I’ve never made music for, and others that I could reinterpret. As an album theme goes, this is a little bit loose — it’s just doing what I do anyway — but the conscious awareness and intent might be enough of a guiding factor.

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