audio compression of mp3 files
 

I have 21 GB worth of mp3 files of audio studies recorded at 64 kbps , 44 khz stereo. I would like to back them up onto cds. This would need at least 30 cds (I have a DVD burner, but then they couldn't be played in mp3 cd players...right?). Could I compress these mp3 files further with lame?

No ... unless you lowered the bit rate even more.

Of course at 64 kbps, they're already ruined, so you might as well

it's not music-just speaking. There aren't any cracks in the speaker's voice at 64-lowering it even more may do that. I'd like to get them onto 12 cds (someone else already did this....I'm not sure how-are there cds that are larger than 700 MB?) There's a -f switch with lame. Does this help compress mp3s?

For just speaking, you can probably go down to 32 kbps, and lame probably would compress them even more because of the variable bit rate

MP3s are already compressed, so simply running them thru an encoder again won't compress them more unless you lower the bitrate. You could probably also lower the frequency to about 32,000 without any discernible loss.