Interesting, I didn't come across Tone.js until now. It looks like it handles a few more things than Howler. Most useful for the drum machine would be scheduling. I'm just using setInterval, which isn't guaranteed to be accurate, but seems good enough for my use case.

I want to build some other browser based audio/synth tools. I'll have dig into Tone.js more for one of those, thanks. I'm re-learning to code with these projects, but the goal is to build a multiplayer web-based modular synth.