Is DEQX a game changer?

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

Thanks Al and Andrew.

Al, may I suggest that you take your initial time alignment measurements a third way ... a baseline measurement. That is, no panels at all. Reason: to see how significant room reflection impact is on the speaker impulse measurements. And conversely, the extent to which your sound box ameliorates room reflections.

Your results will guide me on next steps.

Thanks

Will do.

-- Al

Btw, you referred to "time alignment" and "time coherence." What is the difference between the two terms?
Bifwynne

sorry, I got side-tracked with my other hobby - photography. Processing some pix from a recent air-show & looking into other lens. Darn! why did I have to choose photography + audio both money sinks!!
Thanks for Drewan77 for taking the lead to answer. His reply is mostly correct. Almarg has addressed some clarifications already.

Time alignment is when the speaker designer arranges the drivers in such a way that their acoustical centers are on the same vertical plane. You've seen this done a number of ways: sloped baffle (BTW, that was another great thread!) with the tweeter on top & woofer at the bottom because the tweeter's acoustical center is way in front of it & the woofer's in almost on the driver itself. 2nd way, is what Focal does - makes the front baffle curved. It's an arc of a very large diameter circle. If you put drivers on an arc the distance from each driver to the listener's ear is the same. The tweeter is not on the arc recessed just a wee bit to account for its forward acoustical center. 3rd way, which is what we've seen in Dynaudio's Confidence 5, where the tweeter is at the bottom & woofer on top. The linear distance from the bottom-most tweeter is longer than from the woofer & makes up for the forward acoustical center of the tweeter.
Time-coherence is when a speaker introduces no delays to any frequency in the 20-20KHz range. No driver hence no speaker is linear from 20-20K so you'll see speakers that are time-coherent in the 200-8KHz or 10KHz range. A speaker will introduce a delay in the sound - it has to since it's a causal system but what I mean here is that the speaker does not introduce more/less delay at one freq vs. another. IOW, all freq are equally delayed thru the speaker. When this happens, the leading edge of the tweeter, mid, woofer all arrive at the ear at the same time, as Drewan77 already wrote.
For a speaker to be time-coherent, it will be time-aligned & will also be phase-coherent.
A time-aligned speaker is not necessarily time-coherent.

Simple answer...
You time align speaker drivers or driver sets to each other to 'achieve' time coherence

No, this statement is not fully true. Time-aligning is just one thing to ensure time-coherence. And, it's a physical attribute of the speaker meaning you can see it/touch it. The other very important thing to ensure time-coherence is to use a 1st-order x-over such that the time-delays between any 2 freq & amongst all the freq is not disturbed at all. If you don't do this, time-aligning will have no meaning. When you go thru the math, 1st order x-over ckts are the only ckts that do not disturb the phase relationship amongst all the frequencies.

Many speaker manuf tout their product to be phase coherent. Yes, they are BUT only at their x-over freq & a little +/- of that. This is easy to for a speaker manuf in the biz for any length of time. The key is to make the speaker phase coherent over the entire audio spectrum. This takes special skill & the use of 1st-order x-over ckts that inherently do not disturb the phase. Otherwise you end up compensating for the x-over & by the time you finish the entire x-over is complicated & destroys the music signal totally.

Hope this clarifies....
Thanks.