I'm currently working on-site with an interactive exhibition, which makes extensive use of the Pi. Annoyingly, one exhibit includes three separate (mono) "earphones" where visitors can listen to different sounds. I would normally use something like the JustBoom Amp Zero for anything requiring <=2 channels of high quality audio, or the Adafruit i2s amp for monaural effects and game sounds, and sometimes I use the internals from Logitec's S-150 speakers (USB audio and power), which I bought about a dozen of last year. But now I have the need for three amplified audio outputs and I'm scratching my head wondering what the simplest/most elegant way to achieve this might be. Stacking Amp Zeros is of course not an option, nor is multiple S-150s (too much current draw for the Pi's USB). A separate multi-channel amp is complete overkill. So is using multiple Pis. Combining with the internal audio is not going to be good enough quality wise - and would still require another amp. Same for HDMI audio. Same for a 5.1 USB soundcard.
The more I think about it the most elegant solution seems to be to try and convince the exhibition designers to drop the third sound
Anyone have any clever suggestions?