This thread is long overdue for an update...
Well it has been determined that the wooden mic support jig is at fault for the ragged response while mounted on the baffle.
It was almost three weeks ago Pitviper33 (another Matt
) came over for a few hours during the evening and we measured the response with the mic mounted in the jig vs. the jig moved away and the mic on a normal mic stand/boom. The mic stand measurement was free of the lumpiness exhibited with the wooded jig so the wooded jig must have been at fault. We then tried all sorts of different amounts and styles of damping material to knock out the reflection in almost every position or combination possible. Nothing worked to completely eliminate that reflection, not even coating the whole wooden jig with full 3-1/2" thick R-13 batts of recycled denim insulation!!!
Matt might have some pictures of our feeble attempts.
Here is a measurement comparing waveguide free air, waveguide in baffle with mic in stand, waveguide on baffle with mic in jig. Spaced 5db apart:
So at this time I am going back to the first idea which was to have the baffle rotate and the mic remain in a constant position which will allow me to use the mic stand which I know has no detrimental effects on the response. Matt did suggest an excellent way to setup the baffle so that I do not need to glue in the fiberglass waveguides to keep them from falling out and that is to measure my 0 with the baffle angled at 45 degrees on way then I can move the baffle in the opposite direction so that 45 degree measurement angle will have the baffle flat and at 90 degrees the baffle will be in the opposite 45 degree position.
The real problem now becomes how much time is left to take outdoor measurements. With my trip to Erich's next week I don't think I am going to get a chance to do much more work on it this season.
Back when I started this I thought I could knock this out in a week or two, look how that turned out
So unless I get everything out sometime this next week or Chicago has some really nice weather this November/December I think this project might go into hibernation till spring rolls around.