Yeah, you’re right that this would be a useful feature for audio development in UE4.
So one of my first features was to implement a multiple-audio-device feature which is coming for 4.8. Basically the feature was to create a separate audio device for every PIE session. That way, when you tab between different PIE windows, you’ll hear the audio from that perspective in the way the client would hear it – they have their own reverb instances, voice limits, listener positions, etc. A follow up feature that I haven’t yet done is to selectively solo which PIE session you want to hear audio from. Thus, you could solo one window, tab over to the other and move around, do actions, and hear the audio from the other PIE session perspective.
Since it takes up more resources to basically run duplicate audio engines, it defaults to a max number of 2 audio devices – one that’s the “main” audio device (which renders the audio you hear when flying around the editor and real-time audio is turned on), and the other device is the new audio device created when you create one PIE session. If you have more than two PIE sessions (i.e. 3 windows running the game), the extra PIE sessions will fallback and use the main audio device which is sort of the way it is now. You can enable creating a unique audio device for every PIE session if you’re running more than 2 (up to a max of 8… because apparently we support trying to run 64 PIE sessions on one computer… even though I’m sure that would require a super computer) as an advanced multiplayer feature.
As for muting audio via console command, doesn’t look like that exists. Would be a nice feature to be able to mute/solo sounds per class and pretty easy to do. I’ll see if i can find any time to do it.