I haven't done any A/B comparisons but so far I haven't noticed any negative impact on the performance of the height channels since I put up the curtains. With the ambient nature of the sound coming from them and the extra height from the vaulted ceiling I don't think the proximity to the curtains is an issue but I will be checking that later when the other curtains has been fixed and I have it installed. I have no desire to run the Audyssey setup any more than I have to so I'm waiting.
3M80 2M22 6QS8 2M2 1EP500 Sony BDP-S590 Panny-7000 Onkyo-3007 Carada-134 Xbox Buttkicker AS-EQ1