[feverdream]

Beep.js really isn't a synthesizer, it's more of a step-sequencer. You might want to check out WAD.js, which is more concerned with synthesizing sounds than scheduling them (it has filters, LFOs, other effects, etc). https://github.com/rserota/wad. Full disclosure, I wrote WAD.js.

and btw it's totally possible to make well-timed music with web-audio. I've got a midi keyboard hooked up to web-audio based looper, and that's what I use as my primary instrument these days for practicing. It works fine for me.

[frik]

Impressive. Though your demo works (for me) only in Chrome (no error and no audio in FF & IE11).

[feverdream]

Certain features that I depend on (particularly midi input) are only available in chrome as of right now, so I honestly only test it in chrome, though most of the basic functionality ought to work in other browsers.

[jtheory]

This is the point where I stop and say "oh well, wait another year and maybe then..."

"Evergreen browsers only" is reasonable to ask for lots of sites; but "This site only works properly in the Chrome browser" gives me unpleasant flashbacks to when this notice was everywhere, but the browser was "IE5".