Bit of a Dirac noob here. Just done my second Dirac measurement and filter. I'd assumed direc would give a much smoother response, but though it has tamed a significant mode at about 50Hz (And eliminated Bass Boom as a result) the rest of the response looks similar to Dirac turned off.
I don't use Dirac, using AcourateDRC (lite version of Acourate for miniDSP OpenDRC-DI).
It corrects full-range.
AcourateDRC measures Left and Right, at the listening position, one sweep each. I put the mic between where my ears would be.
Afterwards, I measure Left, Right, and Both, at the listening position. Both speakers adds 6dB to the trace.
1/6 smoothing applied.
JBL LSR 308 before and after:
MartinLogan reQuest (electrostatic hybrid dipole)
Target "curve" was flat.
I make sure I'm centered between the speakers, overlay Left and Right Impulse Response, make sure there is only one peak.
Sometimes what you think is the middle is not.
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On the corrected MartinLogan, you can see a severe dip at 48Hz with both speakers playing that is not evident in either the left or right traces.
Standing wave in this asymmetrical room cause a null when both speaker play.
It's not noticeable with music, and if the bass is stereo, it disappears entirely (or pops up at a different frequency) as the timing of the bass from the speakers is different.
The minor dip around 220Hz is reflection (and cancellation) from the wall behind the speakers.
Both problems also show on the JBL trace, to a lesser degree.
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Why one measurement point"
I figure get one (where I listen) as best possible, and the rest falls where it may. and apparently, that's how my software sees it, too.
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Measurements across the couch - about 6 feet
Trace for the center of the sofa is marked.
Impulse Responses across the sofa.
You can see how, except at the center position, there are two impulses due to the difference in distance to the two speakers as you move across the couch.
Just something you have to live with. Physics.
An extreme case of not having the microphone acoustically centered between the speakers.
More than you wanted to know, I suppose, but I have the traces and did the experiment a couple of years ago.