Convert to 128kbps

Actually, lossy to lossy is pretty well OK as long as both are the same codec. It's moving from one codec to another - e.g. mp3 to m4a - that causes the problems. Codecs work by removing parts of the audio signal that they think you can't hear; higher compression removes more bits. So when you take an already compressed version and re-compress it at a lower bitrate it would remove some of the audio which has been removed anyway, and then remove some more, so there isn't really any difference from comressing to the lower bitrate from an uncompressed version. I don't know whether iTunes compresses itself, though I would guess it probably does. As long as you're not converting mp3 to m4a I shouldn't worry about it.

DW74 wrote:

Hi.

I'm a little unclear on iTunes' option to convert songs to 128kbps to save room on an iPod.

Is it exactly like it sounds? iTunes takes a lossy file, and makes another lossy file from it? Or does it download a 128kbps version of the song and sync that?

I'd hope it's the latter. Lossy to lossy is not ideal.

It definitely does not download a new copy.

Mobile devices are often used in less than ideal listening conditions, and that "compress on the fly" feature is designed for folks who are not requiring high fidelity in their devices. But if you do need the full fidelity, that feature is not for you.