Has anyone any thoughts or experience of transcoding ?

I have several hundred CD's on my PC, ripped at 160-320 VBR MP3.

I've just bought a 512Mb MP3 player (which also plays WMA9), and am thinking of using the WMA format.

However, I don't want to rip all the CD's again (shudder), so I would need to re-encode.

I've tried this on a few tracks, and can't hear the difference, but I've read very bad things about transcoding. The thing is, that the technical explanations don't make a lot of sense. Lossy compression involves removing frequencies that you should not be able to hear (or ones that are deem "less important" at higher compression rates.

Yet people talk about "quality" being removed, and thus being lost twice when you transcode. Whilst you obviously cannot transcode to a "better" rate, and expect to replace missing data, I cannot see that you should loose too much by transcoding to a nominally "worse" rate.

Would be grateful for any information or opinions.

I have don't this mp3 to WMA transcoding, and it's okay, but I still using mp3's purely for the convenience of not having to transcode when I want to listen to audio on my portable player.

Do you want more music or convenience?
More music, use WMA or recompress mp3's to a much lower bitrate than used currently.

If you don't mind mono, use 48kbps bitrate mp3.
For stereo you might get away with 96kbps to 128kbps, although if you're easily annoyed by the audio not being 95% perfect I'd stick to your original files.

Convenience, do nothing.