ToneMatrix

Ooh, I wonder if you could make a Shepard Tone [1]

(I know nothing of music theory so I don't know how to implement it in ToneMatrix's scale)

Edit: it appears making a Shepard Tone requires volume control of each sequence, which ToneMatrix cannot do.

[1] https://en.wikipedia.org/wiki/Shepard_tone

The original ToneMatrix was in turn a knockoff of the Yamaha Tenori-on, which was actually a hardware product - a really pretty sophisticated if sometimes frustratingly limited self-contained controller/sequencer/synthesizer.

Yamaha stopped making the hardware somewhere in the early 2010s, but released a couple of iOS software versions (TNR-i, emulating the original Tenori-on sounds, and later TNR-e which changed the sounds to be more EDM and less... Yamaha).

Inevitably, as software is an eternal treadmill, Yamaha never bothered to update the apps past iOS 13 - but my TNR-W hardware still does the thing, much to the delight of my kids. (I bought one on a whim when my eldest was a toddler - it has survived 10 years of her and then her younger sister's bashing. They're teenagers now! Yamaha makes quality stuff when they feel like it.)

While it never set the world on fire, it also sold enough that used models are still around. If you do buy a used one, note that the original model with the metal case and white LEDs (TNR-W) are worth the premium over the newer white case/orange LED (TNR-O) models; the former are sturdier, have lights on both sides, and can run on AA batteries (TNR-O requires external power).

I remember having a .swf of this 20+ years ago. I wonder if I still have that somewhere on my computer.

You're in for a surprise, https://audiotool.com is a fully-fledged DAW with advanced music synthesis running in the browser.

It actually is where ToneMatrix originates from, and is still one of the useable synths in the DAW!

Since 2020 I built https://sequencer.party

Supports third-party plugins in a format called WAM2 (Web Audio Module version 2).

Collaborative, like Google Docs. Sign in and start a session, invite people. Turn a knob, and it turns for everyone.

Supports audio, midi, and video as well.

Supports custom Javascript sequencers (Function Sequencer plugin). You can (collaboratively) write a little javascript program, give it knobs dials and automateable parameters, and have it emit MIDI events.

There's some usability issues to still work on but it's quite fun to jam on. I used to host twitch sessions where people could sequence my TR-909 and minimoog, and then hear the instruments played back over twitch.

Sadly people with those skills will make iOS apps or plugins, because it’s so much more work to monetize a web app.

Ooh, both of those are very cheery. Thanks for posting them; poking around on my own I was a bit intimidated.

The grid includes three octaves of [C D E G A] plus one more C. (The highest and lowest note are both C.)

I just tried yt-dlp, but its too generic for it to "know" how to download - so didn't work...so i think the suggestion from @stronglikedan is the next best thing...Of course, the absolute best thing would be to propose such a new feature on their github repo. :-)

Just use a separate audio recorder app, since it doesn't have to be hifi for phone sound.

Just open more browser tabs.