Those were mostly copied from the ioq3 description, I've never tried surround sound myself (only got a headset).
I didn't know OA was on SourceForge, too. I do not know who thbrn is.
Let's hope they do not include crapware as SourceForge often does! Although the .zip nature of the dowbload seems a good hint (they often add bloatware in installation programs).
I uploaded those files ages ago, think I've posted them as a mirror as well.
All the files are untouched originals, you can check their SHA1/MD5 on the "view details" popup of each file at SourceForge. This is assuming they do no tamper with them after storage on their server or before/while downloading, so better recheck after download as well.
Sourceforge/oarena is not official fyi. I would never depend on any Sourceforge service, especially not in these days.
I can try to remove the project, if they still allow that. Anyways, as long as you verify hashes and do not click any of the ads, you should be fine for now.