I don't like Barix audio quality, so I would avoid them. I would try APT, Comrex, MDO or BW's codec when it comes out next year, and use uncompressed or lossless coding.
As for the wireless bridge, go 5-5.8 GHz as it's much less crowded (if at all) than the 2.4 GHz and go with a reliable manufacturer. My choice would be Motorola or Proxim.
Regards,
Goran Tomas