If the song is an mp3 file (with compression set to 320 kbps max) it is not further compressed. For the best results, make an mp3 from the original, uncompressed recording. If your song file is in a format other than mp3 or exceeds 320 kbps as an mp3, it will be compressed and saved as an mp3. Pro members are allowed a little higher quality compression level.
Tags: audio, compression, file, mp3, music, song, specs, upload, uploading