The redux from my previous rambling post:

It depends on the ears of your friend.

It depends on the quality of the sound system your friend owns.

It depends on the source you are burning from. For example, the sources could include a store bought CD and MP3s downloaded from N*pster. With a downloaded MP3, there is no way to improve the sound quality. It is what it is.

Now to your new questions:

Music is lost when creating 128 kbps. As an example, a 50 Mb WAV will be compressed into a 5 Mb, 128 kbps MP3 file. If you convert the MP3 back to a WAV, the WAV file size will be less than 50 Mb and the sound quality of the round trip WAV file will be the same as the MP3.

It is pretty simple to test out the sound quality of the various kbps MP3s. All you need to do is rip one WAV file from a CD and make MP3s at various densities. You will see by the file size the various levels of compression and you will hear how the quality varies with density.

BD