Audio compression works by removing whole chunks of audio from the frequency spectrum (e.g. things *supposedly* you don't notice anyway). Lossy compression will *always* do damage to the original audio. So, naturally, it is a bad idea to recompress already existing material, unless the recompression is not done at a reasonably higher bitrate (i.e. 128kbit recompress to 160, or 192 even). Also I'm experiencing noticeble artifacts with m4a > atrac3. Might be the way math works in the software.. In your case some recompression might be taking place, and it would most likely be the source of your bubbling noise. I have noticed that SonicStage would apply recompression at will, unless instructed not to do so. Things that will help: 1. Upgrade to latest version of Sonicstage. 2. Fiddle with the options to make sure: - all you transfer is reasonably high bitrate. Be generous with bitrates. - ideally no recompression occurs (i.e. transfer as is when possible) 3. Redo your library again. Something I do: Keep my tracks outside Sonicstage, in v.good quality, and manually recompress to a sony bitrate on transfer.
