As the title says Bandcamp audio will not play. Youtube is fine so html5 streaming is working. From searching the internet it seems this may be a Flash issue. I have tried various solutions to no avail, this seeming to be the most recently (supposedly) working one....
Please get Opera working with all streaming media!!
Opera's poor html5 support is to blame once more, because the files on that site are simple mp3 ones, which opera's built in libffmpeg.so does not support. There is no flash at all.
If you are on ubuntu, install chromium-codecs-ffmpeg and chromium-codecs-ffmpeg-extra.
Finally, youtube's stuff plays because they can be also streamed as webm. If they were only h264 mp4 files, they would not play as well.
It's already fixed in Opera Beta and Opera Developer edition. It should be also fixed soon on Stable channel.