What a lot here fail to understand, its the RMA, that controls the limits on noise, and really has sod all to do with MSNZ or the circuits, and you have have the NIMBY following, which puts the dampeners on over "limits' noise. I think Hampton Downs is the only circuit that has taken a good look at how to go about this when applying through the RMA to set their levels, even Highland Park have restrictions placed on them.

Roger