I find that BB/RB work at CD quality, which means 44K sampling rate, and 16 bit data-byte (size) accuracy.

If you are using LAME in BB/RB? then that could be the problem. You'd need to match their specs, would say.

If you use LAME in Audacity, then the limits are usually by the sound card, and it helps if recording directly, and simultneously "what you hear" which bypasses PG, specially voice coming in and external sound moules coming in.

So "improve quality" can not be done beyond that spec, to recorded Real Tracks, for instance. Those are as said, 44K and 16 bit. Good enough for me, though.

Also, you notice that if you load any thing higher in resolution, from another source, BB/RB will immediately use a resampler.