If I upload an audio file, does Roblox use it as-is, or standardise it first?
If it standardises it, then there’s no reason for me to not convert the music to a lossless format (as long as it’s under 7MB), because it’s going to be compressed later so there’s no reason to have three lossy conversions instead of two (? -> MP3 -> OGG -> ? as opposed to ? -> MP3 -> WAV -> ?)
However, if audio is not standardised, then picking a max-quality WAV/OGG will impact load times, and I don’t know enough about the formats to know what the lowest quality is that almost perfectly replicates a 320kbs MP3.