Changing bit rate: no effect on size

L.S.

To prepare audio files for podcasts, i am exporting audio files which have been exported at a 128 bit rate before, as mp3’s with a 64 bit rate. Unfortunately, sometimes this has no real effect on the size of the files (say, 1 MB less, on 50MB file). How could this be possible?

Thanks!
Niels

Were they mono when you imported them and stereo when you exported? That would explain it.

Also be aware that at a bit rate that low, the sample rate will change (this is the way LAME behaves, it’s not an Audacity thing), so people might have trouble playing them.