I just thought I would post an update to my Audyssey EQ problem.
I have made a major breakthrough! I never thought I would get past the harsh metallic grating sound of my first several attempts but I did. I wanted to post what the problem was and what my work-around was just in case others are also having this problem.
My center channel speaker sits beneath my TV near the floor. It is angled up to the listener's ear position so it sounds fine when sitting at the couch but this caused problems during calibration. The problem is that the base of the mic provided with the Onkyo is very large and after it is mounted on a tripod and pointed directly at the ceiling (per the instructions), the sound coming from the center channel is nearly totally obscured by the base of the mic and the tripod. This causes sound from the center channel to not "graze" the mic correctly which I suspected caused a high frequency roll-off during measurement that Audyssey was trying to correct for by boosting the highs! This definitely seems to have been my problem.
I found that if I angled the mic on the tripod so the mic opening was at a 90 degree angle with the center speaker baffle, the sound could perfectly graze the mic opening. The result was a MUCH smoother, more natural calibration in the center channel without any of the brittle, metallic character of prior calibrations.
The next problem was, my left and right channels are mounted higher on the wall flanking my screen and the center is under the screen quite a bit (several feet under the left and right channels). I know this is not optimal but it is all I can do at the moment. So, the front speakers are angled down to the listener's position and the center is angled up to hit the same listening position. I am also only sitting abut 10 feet back from the front speakers so these angles are pretty pronounced.
My workaround: I used a laser level to first angle the mic to a 90 degree angle from the left and then after the test chirps ran, as quietly as possible, again using the laser level, I changed the angle of the tripod to point the mic down 90 degrees from the center speaker and then again left the room. Once the center chirps had run, I re-angled the mic in the proper position for the right channel and left the room allowing the chirps to run. I repeated this process measuring in 8 positions for my calibration. It was tedious but worth it.
The results are MUCH better now. Everything sounds balanced and neutral. There is less mid bass than what I was use to prior to calibration but honestly I would expect that and it doesn't sound bad at all. I can now turn the volume up to -10db from reference as I did before calibration and it is no longer painful with ear-splitting highs and mids. I am VERY excited now!
Some final thoughts... I was concerned that my work-around (changing the mic angle in the middle of calibration) was not good because it could introduce more problems with phase and the noise floor, etc. So I asked Chris at Audyssey about it and his response was as follows:
"I am very happy to hear that! I am impressed that you took such care to optimize the mic position between measurements. It's tricky, but if the signal did not repeat then it's fine. MultEQ takes a quick room noise measurement before and after each set of chirps, but then there is some dead time due to data transfer and calculation. So anything you do during that time is no problem."
In regards to my complaints about the mic Onkyo supplied, Chris had this to say:
"Your comments about the mic are also very correct. We have produced our own mic that does exactly what you say: Taller and thinner. But Onkyo didn't adopt it for this round of receivers. Denon and other licensees already have."
This is very interesting to me. I have asked Chris if the new mics will work in the Onkyo or if the calibration curves are different. I will post what he tells me. This is definitely something to consider if someone is considering an Onkyo vs. a Denon.
I hope this post can help others. I am very happy with Audyssey now. The imaging is phenomenal. Everything just snapped into place! If any others are having poor sound quality with Audyssey, please check to see that your mic opening is 90 degrees in relation to your speaker baffles and that nothing is obstructing the radiation of sound from the speaker. It makes a MAJOR difference!