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When using Web Audio, you can connect all sounds you create to one globally created gainNode and use that node to have a "Master Volume" property. This is very handy when you want to be able to change the master volume on the fly and want it to affect all sounds immediately.

Now, I am trying to accomplish the same, but for playbackRate. For reference: this would be for a web game where you can use a power-up to slow down time, which should also slow down all music and sounds.

Each sound I create is a AudioBufferSourceNode linked to a chain of processing nodes. Now I know that the the AudioBufferSourceNode itself has a playbackRate property you can change. This is great, but it'd require me to cache all AudioBufferSourceNodes I create, loop over them and change their playbackRate if I wanted to change a "global playbackRate" on the fly. It'd be perfect if I could accomplish this in the same way as with the global gainNode, but couldn't find a way to do that.

What would be the proper way to implement such a feature? Would you recommend caching all AudioBufferSourceNodes created (can be thousands) and loop over them? That's the way I do this with HTML5 Audio, but it seems hacky for Web Audio, which is much more advanced.

If you want more information, please ask and I will update the question!

Dysprosium
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You can't directly do that. There are some source nodes that don't have playback rate controls - like live input. In this case, you're best off doing what you suggest - keeping a list of active sounds to loop through.

You could use a granular method to resample and pitch-bend it down - like the "pitch bend" code in my audio input effects demo (https://webaudiodemos.appspot.com/input/). That's a bit costly to keep around just in case you want to make the effect, though.

cwilso
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