bitrate 101 .. sounds like chipmunks at low bitrate

[SteveLionbird]

I normally broadcast a folder of mp3's at 96kbps 44khz stereo ..
If I change encoder to lower bitrate .. I either cant hear anything when I tune in .. or the audio sounds very high pitched and sped up like chipmunks.

Can someone please tell me why this is? I understand that others can stream both low and high bitrates without a problem (encoder 1 & 2).

Does this have to do with the encoding of the files themselves? ... if so, how must I encode them to accommodate both low and high bitrates.

If not maybe a codec issue?

Thanks,
Steve