I have 4 different displays set up in a booth and I want to be able to have someone press a button and hear an audio playback for that particular display. I am trying to determine if the RPi 2 has the capability (maybe with PulseAudio or some other app) of sending different audio playback to different speakers at the same time. So, if 1 person walks up to display A and presses the button, the audio for that display starts on that speaker; but then someone presses the button for display B while display A is still playing...display A needs to keep running while B starts playing on that speaker. Is this even possible?
Yes, should be possible
(While I don't understand whether those "displays" are supposed to show some kind of graphics output), it is possible for the Pi to source multiple different audio outputs. One simple approach is to use multiple USB sound cards.
alsa is perfectly capable to handle multiple cards (see here). Different software tools or multiple instances of the same should then be able to output different sound files to those cards.
The information on the web is slightly inconsistent, some claim that both
mopidy support multiple instances running other say the don't.
Example, Pi2, with
mopidy running (controlled by a local instance of
ncmpcpp which essentialy uses no resources) while playing MP3 uses about 25% of total CPU load. So this could get you to roughly three or four independent sources of sound. At least from a resource perspective.