Before putting away the measurement rig, which I've decided I must do at least once a week to maintain sanity, I made one last measurement of the Left channel, with 0 degree calibration file loaded. (Actually, part of the purpose was to be sure I was loading the calibration file correctly, which requires remembering to tick the box "Use with frequency response" and the "OK.")
It's only slightly different from the uncalibrated response, with some differences above 10kHz and especially below 20 Hz. To see below 20 Hz or above 20kHz with ARTA, one has to remember to use the scroll or zoom controls on the right side. It extends to respectable limits beyond. Until I discovered that, I was cursing the limited 20-20kHz range.
The frequency response graph shows a few problems that should be tackled before moving on to phase linear crossovers, at least with regards to likely audible consequences.
Probably the most important if the rear wall reflection notch at 200 Hz. I thought I had fixed that by moving speakers farther from the wall. Indeed, the notch used to be at 250 Hz and bigger. Also it gets covered up when the region around 100 Hz isn't equalized properly. But when 100 Hz is equalized to roughly flat, then it is obvious there is a large notch at 200 Hz. Currently this problem is limited to the left channel for some reason.
It would be nice if I could ameliorate this without going to greater complexity, such as using the midrange driver in the supertweeter box for fill-in just in this notch range. (That would make the linear crossovers thing even more complicated.)
Another bit that bugs me, but probably not very important, is the depression just before the supertweeter takes over. That relates strongly to the high frequency crossover. I possibly need to equalize the Acoustat output around 14kHz where there may be some kind of resonance, so I can make the acoustic crossover "tighter" without causing a huge peak. That's been the limitation so far, I can't fix the dip without creating a huge peak at 14kHz instead. That needs to be fixed before trying to make the high frequency crossover linear phase.
Finally, the Linkwitz dip from 2-6kHz is not well done on the left channel. Instead of a dip, it has a bulge around 4 kHz. Most of the EQ tuning for that was done on the right channel, and I haven't used separate L and R settings. I will need to have separate Left and Right equalizations going forwards to deal with things like this.
But meanwhile, I also need to apply time alignment to my two other subwoofered systems, the kitchen and the bedroom. The time alignment for those systems has never been properly measured or adjusted. (That was true of the living room system also, until last week.)
I also want to check out the digital jitter resulting from the use of the miniDSP's and other new features, such as my Kanex Pro de-embedder which is now used to extract PCM from HDMI while I am playing SACDs.
It's only slightly different from the uncalibrated response, with some differences above 10kHz and especially below 20 Hz. To see below 20 Hz or above 20kHz with ARTA, one has to remember to use the scroll or zoom controls on the right side. It extends to respectable limits beyond. Until I discovered that, I was cursing the limited 20-20kHz range.
The frequency response graph shows a few problems that should be tackled before moving on to phase linear crossovers, at least with regards to likely audible consequences.
Probably the most important if the rear wall reflection notch at 200 Hz. I thought I had fixed that by moving speakers farther from the wall. Indeed, the notch used to be at 250 Hz and bigger. Also it gets covered up when the region around 100 Hz isn't equalized properly. But when 100 Hz is equalized to roughly flat, then it is obvious there is a large notch at 200 Hz. Currently this problem is limited to the left channel for some reason.
It would be nice if I could ameliorate this without going to greater complexity, such as using the midrange driver in the supertweeter box for fill-in just in this notch range. (That would make the linear crossovers thing even more complicated.)
Another bit that bugs me, but probably not very important, is the depression just before the supertweeter takes over. That relates strongly to the high frequency crossover. I possibly need to equalize the Acoustat output around 14kHz where there may be some kind of resonance, so I can make the acoustic crossover "tighter" without causing a huge peak. That's been the limitation so far, I can't fix the dip without creating a huge peak at 14kHz instead. That needs to be fixed before trying to make the high frequency crossover linear phase.
Finally, the Linkwitz dip from 2-6kHz is not well done on the left channel. Instead of a dip, it has a bulge around 4 kHz. Most of the EQ tuning for that was done on the right channel, and I haven't used separate L and R settings. I will need to have separate Left and Right equalizations going forwards to deal with things like this.
But meanwhile, I also need to apply time alignment to my two other subwoofered systems, the kitchen and the bedroom. The time alignment for those systems has never been properly measured or adjusted. (That was true of the living room system also, until last week.)
I also want to check out the digital jitter resulting from the use of the miniDSP's and other new features, such as my Kanex Pro de-embedder which is now used to extract PCM from HDMI while I am playing SACDs.
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