I did some tests with a couple Audiences a while back, I have the configuration I used here: http://forum.mikrotik.com/t/using-wifiwave2-to-bridge-two-audience-wirelessly-thoughts-4-address-mode/153357/1
Apparently I was using “skip DFS” – more interested in stability than max speed so why risk a DFS event (or bug). Why I wouldn’t like have gotten any >80Mhz.