Just discovered this thread, fantastic tutorial, an easy and efficient way to perform room/speakers correction in the frequency domain. If there is a Roon Award contest, @magnus you have my vote!
There is no doubt that the spatial averaging technique of the moving mike technique across your preferred listening area allows for a very efficient correction of the speakers and room in amplitude, at least as good as Dirac & Co.
Amplitude correction is the indisputable STEP 1 that any “dematerialised” audiophile has to implement. The cost is ridiculous against the benefits. Consider it before buying any cable of any kind above 100$ (price of the microphone). STEP 0 is of course to ensure proper placement of the speakers and listener, as well as room treatment is feasible.
My experience is that the audio message and soudstage can be further improved with additional corrections/convolutions, that can come on top of the amplitude correction (Roon allows to chain convolutions so you can pile up as many as your processing power allows).
STEP 2 : correction of the phase curve and time alignement of speakers : the impact goes from “no change” to “wow” depending on your speakers and personal sensitivity. I recommend to try it if you listen a lot of acoustic recordings, percussions, guitars… The dynamic and clarity should improve. Dirac/Acourate/HAF/Audiolense do it pretty well with a cost (evaluation is free though). You can implement it for free using REW in combination with Rephase but it requires some time and is a bit more technical than the RTA/MMM amplitude correction presented by Magnus.
STEP 3: further help your brain to feel you’re with the musicians
Hifi is about creating an illusion of you being with the musicians playing in a studio, a concert hall, a jazz club… Frequency balancing of the reverberant sound corrects the unnatural tone of the reverberation caused by the directivity pattern of your speakers and the specifics of your room (for example if you have an irregular reverberation time over the spectrum, check the RT60 screen in REW under “Overlays”). The brain doesn’t like it because it’s not natural of a studio/concert hall/jazz club. I have implemented this correction in my (difficult) room and got a terrific improvement in the soundstage despite the absence of any room treatment. The walls have disappeared, the soundstage is super-wide (goes well beyond the walls !).
X-talk reduction is in my view is a must if you listen a lot of acoustic “live” recordings made with dummy heads or standard stereo recordings (two microphones, one for “left ear”, one for “right ear”). These recordings are fine when listened to via headphones. But when listened with speakers, what comes from the left speakers goes to your left ear AND right ear, same for right speaker ! This is the X-talk. Quite strangely it is not proposed in standard by DSPs even though it is not that difficult to implement.
In my case going through STEP 3 provided a lot of benefits on most of my records, with no negatives. I went through HAFservice and they took care of STEP 1/2/3. (NB: I am not affiliated to HAF in any way, and paid for the service, actually 3 times cheaper than Dirac). It would be good if bigger players like Dirac could provide such advanced features ! We discuss it here and also here.
EDIT: tor those interested here is my view on the current market offering for room/correction/convolution. One could add a column for the REW/MMM/RTA approach documented in this thread : Amplitude correction only (the most important thing to do anyway), quite easy to apprehend and implement, and completely free, except for the cost the microphone of course.