Is DEQX a game changer?

Andrew (Drewan77), thanks again for your always excellent inputs. A couple of minor clarifications to your post just above, if I may:

Sound waves travel at different wavelengths/speeds from the lowest/slowest to the highest/fastest frequencies so what you are aligning to is a subset of all.

Although the velocity of a sound wave in air does indeed vary as a function of frequency, as I understand it the amount of that variation is small enough to be negligible for practical purposes. See the graph near the lower right corner of this paper, where it can be seen that even under the worst case condition (0% humidity) a frequency of 10 Hz is less than 0.03% slower than a frequency of 20 kHz. At a listening distance of 3 meters, that would result in a propagation delay difference of less than 0.003 milliseconds between those two extremely different frequencies.

With a single full range speaker containing passive crossovers, or a 2-way, 3-way measured accurately at once (ie without requiring subs), then an appropriate DEQX processor will do everything for the user and it automatically becomes time and phase coherent.

But of course only to within a degree of accuracy and over a range of frequencies that are constrained by the duration of the correction window and by reflections that may be captured within that window.

Thanks again, though, for another excellent post. Best regards,
-- Al

Thanks for pointing that out Al, no problem at all!

I have always tried to keep my posts quite generalistic because we seem to have several potential or new users here and many of the principles behind DEQX can seem pretty bewildering at first, offputting even

Al and Andrew (Drewan) ... if I was inclined to put together a non-reflective sound box, do you have any thoughts about the materials I should use? I wonder what speaker manufacturers use to damp sound reflections in box speakers??

Andrew, notwithstanding the imperfect initial set up of my speakers because I was not able to do the time alignment adjustments outside, imaging and soundstage are greatly improved over what I had before. In many ways, I was playing stereo through two different speakers because of room EQ problems. I think you have a sense of what I was dealing with by looking at Larry's adjustments.

I'm sorry, I am not experienced with materials for acoustic panels. Maybe Nyal could comment as I have seen a couple of recent posts from Acoustic Frontiers

Acoustic panels are not one of my areas of expertise either, Bruce. But if you want to DIY at a low price, the suggestions Bombaywalla made earlier of Owens Corning 703 or 705 seem worth looking into. They can be ordered via Amazon, where lots of user comments and Q&A's are provided.

Also, although at higher price points and not DIY, you may want to look into the suggestion Nyal made earlier of the HF versions of some of the RealTraps.

The Clearsonic panels I ordered, btw, will be arriving here on Tuesday. I may not be able to report results until the following week, though, as I'll be occupied with other things during most of the coming week. Also, I've been envisioning that when I move the speakers toward the center of the room for the close-up measurements, in my particular room surrounding the mic with the panels is likely to be more beneficial than surrounding the speakers with them. But I may try it both ways.

Best,
-- Al