Multi track example could have mixing capabilities about webaudio-examples

[chrisdavidmills]

Nice ideas here @matt-eric. I think I'd prefer that you submit these changes as a new version of the demo alongside the original (call it something like "multi-track-advanced") — that way we are not in danger of obfuscating what this demo is trying to illustrate, and we don't need to update the associated MDN tutorial to explain all the new code ;-)

[mattfsourcecode]

Good plan @chrisdavidmills. I will make this into a new directory and leave the original as is.

[bsmth]

Thanks for reporting! I'm going to close this due to inactivity, but if you're still interested in tackling this, feel free to reply or open a PR with Chris' suggestions! Thank you :)