Hm. I've been doing 128 constant. Should I be recording with VBR?

Yes. I recently switched from 128 constant to VBR, and it's much better to my ear.

If you take two MP3 files of equal size, one of them at 128 constant and the other one at VBR, the VBR will have less artifacting in the high frequencies.

Tony Fabris
Empeg #144