WebAudioAPI musical application: clicks and crackles and abrupt stops

This is some kind of continuation of my other post about the same argument.

I'm developing a musical web-application using the Web Audio API that basically works like this: the user navigates through a full-screen image, on which there are some specific points associated with specific sounds. The app plays the sounds that are closer to the user, and fade them out when the user gets away.

I'm facing a couples of problems that I cannot understand.

1. as told in the previous post, sometimes scheduled fade out are ignored and the audio content is abruptly interrupted.
2. the second (and more annoying) problem is regarding clicks and crackles that sometimes occurs during the navigation.

Talking about the issue number 2, the curious fact is that the issue appear to be non-deterministic, sometimes happen and sometimes not (on the same machine, with the same browser). I figured that it's probably a performance-related issue, but I can't tell what causes it. I tried removing the heavy audio effects (such as convolution reverb or binaural spatialisation) but the noises still occurs sometimes. Now I rolled back to the full-features version (with effects).

You can see the complete source code here: https://bitbucket.org/splsteam/splswebapp/src.

In the README you can find a link to the beta version. You'll need the following credentials to login:

• Username: webwallwhispers
• Password: rete muro sussurri (with the spaces)

I know is not easy, but maybe someone had a similar problem.

Thanks in any case, Francesco