How treat the monitor wall @ ceiling

You know that space (the wall actually) ABOVE the console (and above the control room glass) where it meets the ceiling? Most studios have this angled out and we're about to FINALLY treat this spot in the studio here. What is the thinking there? I know its "kind-of" like a bass trap, but is it a filled space? CAN it be somewhat hollow (resonance free of course)? Foam? Absorptive? Semi-Reflective? Diffused? Semi-Diffused? We always use Fibonacci's golden rule (0·61803) for angles but what about materials, density and leafing? Michael Scott

It can be fairly light, if it's filled with fairly heavy insulation - 703 or rockwool, for example. This would then act as a minor panel trap to lower frequencies, and improve RFZ for mids/highs. That said, if you're doing 5.1 mixing you want all surfaces absorptive so you don't get early reflections from the surrounds off the front walls. Also, if that corner is now square, whatever sound (above maybe 250-300 hZ) that goes into the corner, will come back out exactly parallel to itself for a nice short secondary reflection path (hello, comb filtering...) It seems that most/all the actual pioneers in surround are now doing the dead room/add digital ambience approach in order to get away from the surrounds > early reflection problem... Steve

Thanks Knight! Check out the pic - it's an especially tricky fix. Yes the heating/cooling duct is being removed:

Also - should I stand off ALL the panels (acou cloth over mineral board). Make 'em all connected laterally, as oppossed to that 1.83" gap? We thought the gap would add interest and a micron (a quark maybe?) of diffusion. Anyway, as you can see the ceiling has to be done too - clouds I think in this room using http://www.amdx.com/studiox/profoam.htm Thoughts?

"Yes the heating/cooling duct is being removed:" - good; about the only worse place would be if you had a PAIR of them, one over EACH speaker... I would lose the gaps at the front of the room; instead of diffusion, you'll more likely end up with some wierd specular reflection/diffraction points that could shorten your trip to the rubber room (no, not the vox booth :? ) Another thing - look at your speakers, then read this http://www.genelec.com/support/faq/faq21.php Plus, when making any changes to speaker placement I would keep any height differences between speakers and ears to a minimum (without getting other stuff between you, of course) - Phillip Newell explains this in Recording Studio Design; basically, the pinnae (those little, apparently useless bumps just in front of your ear holes) aren't quite as useless as we once thought. Newell found out through semi-accidental means that identical speakers placed higher gave worse HF response (with subsequent errors in mix decisions) than lower placed speakers - seems the pinnae are responsible for height sensing in our hearing, probably to tell whether we're being attacked by an eagle or something - anyway, unless you're prepared to lean back all the time while mixing, it's better to have speakers at head height if possible in order to get a more uniform treble response. Another reason for lower, more level speaker paths; less bounce from floor behind, which can end up returned as an early reflection in some cases (perhaps off the floor > producer's table/rack front > mix position) Guess that's all the questions so far; hope it's helping... Steve