Originally Posted by noah katz
I realize it could reach novelesque proportions, but it would be really interesting to hear at least a summary of what Curt and Remi did, in particular if there was something in particular that resulted in a sizable step up in SQ
Pretty systematic process: (1) test and measure each speaker without any correction from multiple seats, (2) "fix" gross errors, (3) take multiple measures around the various listening positions (looking for anomalies), (4) create first pass correction curves, (5) critical listening, (6) refine correction curves, and (7) create a range of preference curves. Remi also did a general noise measurement for the environment, which helped me to identify a door that wasn't properly sealed.
In steps 1 and 2 they/we discovered a wiring error where several of the subs weren't firing: each of the five subs tested fine from amp to sub, but a loop circuit wasn't wired correctly for the system of five subs. We discovered a phase issue that improved both mid/high driver integration across the fronts and speaker localization for the spatial location routines. And, they found a way to increase the amount of "direct" energy for the fronts at higher frequencies, which helped the spatial location routines perform better, which we later removed in the correction processes.
In steps 3 and 4 they established six measurement spots for the sweet spot location, which was my overwhelming emphasis, and confirmed that it was largely ok for the other primary seats. They were also able to determine that what appeared to be a broad lower midrange depression was in fact a collection of narrow and deep dips that were getting "smoothed" by the 1/3rd octave user interface display. (Those were a result of constructive interference path length differences off of a nearby bar transition area that I've since ordered some acoustic products to address.) Curt also adjusted the target curves to eliminate correction at the low end where effects speakers didn't have adequate output, and, above 150hz or so on the subs. In effect, he used the target curve editor to "suck the energy out of the speakers" in the ranges where they were likely to be distressed.
In steps 5 and 6 we were playing with 1db tilts in the high and low ends. In step 7 we added some additional "oomph" and "tilt" to those. I ended up using 2db down at the high end and 3db up in the bass as my music setting, with movies being another 2db down and 3db up, respectively.
It sounds very nice.
And, it's pretty cool to watch the input and output meters when they show the center, two sides, two heights, and four rears all firing when Stereo is playing on the inputs and Stereo is selected as the listening mode. I no longer covet Trifield as a surround synthesis mode.