The suspense is killing me.
The FR of the microphone is different for each orientation wrt signal source.
Not Selden, but... the main problem is that the 'grazing angle' of the mic is not what Audyssey expects. As you know, the mic is supposed to be pointed vertically up to the ceiling - but this assumes that the speakers are more or less at ear height. Clearly, when one points the mic up towards the ceiling and ceiling speakers are in use, the grazing angle is vastly different to what Audyssey expects, and this will skew the frequency response of the mic. It could even be similar to pointing the mic directly at a regular speaker, which is something I know you would never do, even under pressure of torture and cruel and unusual punishment :)
It isn't very easy to make a recommendation for anyone with ceiling speakers because by definition the mic will be orientated differently towards each speaker, typically. I think we just have to accept that this is a limitation in Audyssey MultEQ, which wasn't designed with ceiling speakers in mind. Perhaps I ought to add this to the FAQ?
I should have picked up on this and I apologise for not doing so. I think I need to add a 'ceiling speaker' question to the FAQ.
Maybe, Fitz. But...
In the good old days, Chris commented that the grazing angle had some significance and was the reason the mic should be pointed to the ceiling. If it made no real difference which direction the mic was pointed in, then we ought to be able to get a good calibration with a conventional speaker setup by pointing the mic directly towards the speakers. I doubt if many would agree that this was a good idea though ;)
What would you suggest as to the reason why Audyssey struggles so much with ceiling speakers?
My Height speakers probably present a similar angle to the mic too. But surrounds and height speakers are far less critical than the main speakers and so the impact of calibration on them is likely to be less. Indeed in the REW thread we ignore the surrounds and height speakers totally of course. In my reply earlier, I should perhaps have made it clear that I wasn't commenting specifically on any one situation, but in general. If the main speakers are mounted in the ceiling, it seems Audyssey struggles to give a good calibration from them. Other than the abomination that are ceiling speakers (IMO) it would seem to me to be the way off-SOP of a grazing angle that is the culprit, but it is only speculation of course.