The original Dirac system was conceived to assist in designing car audio systems, which are distinctive in that the individual drivers are distributed all over the place and need to be coordinated to deliver intelligible sound to a few listeners, all in the wrong locations for stereo. Hence the need for time domain manipulations. It is elaborate, in situ, loudspeaker system design. When applied to home theaters such concepts need reconsideration.I understand averaging of responses, and how it works. I'm just a bit puzzled on the impulse response correction and the supposed benefits.
Here's some of the information I found.
There's more stuff on their website such as time-aligning of drivers, phase correction etc , which I don't doubt it'll do... Seems all you need is any room and any loudspeaker, and Dirac will turn it into a great experience
Figure 12.4(f) in my book shows that the Dirac default target curve is almost exactly the steady-state room curve that results from using highly rated loudspeakers in normally reflective rooms. Some call it the "Harman" curve. At the time I wrote the new book, my old book was the only technical reference in their manual. It needs to be noted that this is not a target room curve for loudspeakers with flaws, but that is not what "room EQ" implies. In fact reading the details in some of the manuals for such systems the instructions are to try things with the suggested curves. The fact that there are sometimes several suggested curves is a clue that this is not a precision "calibration". It is an admission that the room curve is not a definitive statement of sound quality, which is a fact. If that does not sound good they provide user friendly methods to change the shape of the target until it sounds better. This is not a calibration, it is a subjectively guided equalization, with the circle of confusion included because decisions are made by listening not measurement.
As humans do not hear phase, correcting impulse response is not necessary. However, phase matters in crossovers between drivers - as in the original car audio application of Dirac, but not in home theater.
EQ at low frequencies is almost essential, and because bass performance accounts for about 30% of our overall sound quality ratings it is very important to get it right. Above the transition/Schroeder frequency, if the loudspeakers have been well chosen, nothing may need to be done except gentle tone-control adjustments and these will change with different programs.
The claim that Room EQ can turn any loudspeaker in any room into a flawless system is rubbish, but there are people who believe this. This paper, and my book explain it: Toole, F. E. (2015). “The Measurement and Calibration of Sound Reproducing Systems”, J. Audio Eng. Soc., vol. 63, pp.512-541. This is an open-access paper available to non-members at www.aes.org http://www.aes.org/e-lib/browse.cfm?elib=17839