Hey Maybe someone from Needle will answer with some alternative solution.
The Voip doesn’t seem to be ready for effects like that out of the box…
But if you open up the Voip.ts, you’ll find that the AudioConnection has a currentAudio which is type of THREE.Audio. That takes us to Three.js docs https://threejs.org/docs/#api/en/audio/Audio.filters, where there is a filter property controlled by setFitler / getFilter.
I wasn’t exactly able to find any example code on possible filters, but i think it is definitly doable, since now you are in the realm of pure Web dev / three.js specific implem of it.
So one variant would be to add filters to the AudioSources that are being played. Effect would be applied while “Playing the sound” of the remote user on your local device.