Music and AVP and Signal Processing can embed audio files via the SoundCloud player. Since the feature already exists, it would only need to be activated for PPCG, and judging by Signal Processing the devs will actually do so if there's some support in the community for it.
Why I think this would be useful: We've had a handful of audio challenges, and I'm sure we'll have more in the future. But in general these are not as popular as graphical-output or image-processing. Part of that might be people being less familiar with audio than graphics, but I think a major problem with audio challenges is that you currently cannot easily listen to the results, like you can look at the pictures produced in graphical challenges. I think that's quite a barrier for these challenges, and we could do a lot more interesting audio-based challenges if we could embed the results right in the answers.
So please indicate your opinion by voting the question up or down, and leave a comment or an answer if you want to add something. And if this gets some support, I'll ping a mod to ask the devs if they could activate this.