Is DEQX a game changer?

It's not possible to answer that question Ptss, I'm afraid because there are too many variables involved, not least the impact the room has on the sound and your ability to optimise that.

However speaking personally, I am confident from the experience I have that DEQX can significantly improve any speakers/room you would be confronted with because I have already done this several times using a DEQX processor.

The JBL 250Tis are a 3-way design and if you are brave enough to do it, bypassing the internal circuitry and using 6 channels of amplification (ie HDP-4 OR HDP-5) and digital crossovers are what I would do.

Even a Premate or Express will help you get the best from these without modification but whatever you consider, the end result will only be as good as the time and effort you are prepared to invest.

I finally found the time today to re-do my speaker measurements, as I had previously indicated I was planning to do. A link to photos of the measurement setup and screenshots of some of the measurements is provided further down in this post.

Once again I moved the speaker being measured to the center of the room. However, instead of positioning the large acoustic panels I had purchased (Clearsonic S5-2D's) close to either the microphone or the speaker, as I had previously done (which created early reflection problems from the panels themselves), I positioned one of them in front of the fireplace on the left, and one in front of the large antique radio/phono console on the right. I also positioned a third panel, which I purchased subsequent to performing those initial measurements, on the floor, under the mic stand and extending to the front of the speaker. It pretty much eliminated a significant floor reflection that was evident in the earlier measurements, despite pillows having been placed on the floor at that time.

The panels on the sides were located 50 inches from the nearest side of the speaker. The front baffle of the speaker was 10.5 feet from the wall and window behind it. The nearest objects in front of the speaker were for the most part around 7 or 8 feet away, and not directly in front of the speaker or directly behind the mic, although some objects off to the side were as close as 5 or 6 feet.

I measured each speaker from distances of 30, 36, and 42 inches. The 30 and 42 inch measurements were performed with the speaker grilles removed. The 36 inch measurements were performed both with and without grilles. As it turned out, though, the 36 inch measurements looked essentially identical with and without grilles.

I've uploaded to flickr.com three photos of the measurement setup, as well as a set of screenshots of the 36 inch measurements sans grilles. Each of the screenshots includes measurements of both speakers, superimposed, and with no smoothing. You can see all of this here.

Looking at the impulse response screenshots, the small wiggles occurring at around 14 ms (about 8 ms following the direct sound arrival) I'm pretty certain are a reflection from the ceiling. What strikes me as perhaps the most significant concern, that I see initially, is the spike in the impulse response occurring just 0.7 ms after the direct sound arrival. I'm not sure what that is, although based on its arrival time I suppose it figures to be a baffle reflection.

In the coming days, or more likely weeks, I'll be creating and sonically assessing a number of correction profiles. When I settle on one that seems best, I'll then address room corrections, which I haven't addressed at all so far.

Apologies for the slow progress to those who may be interested in the conclusions I'll ultimately reach.

Best regards,
-- Al

P.S. to my post just above: When I said ...

What strikes me as perhaps the most significant concern, that I see initially, is the spike in the impulse response occurring just 0.7 ms after the direct sound arrival. I'm not sure what that is, although based on its arrival time I suppose it figures to be a baffle reflection.

... I'm thinking that perhaps it also could have been a reflection from the mic stand.

Can any of the experienced DEQX users offer an opinion as to how serious an issue that spike, and the subsequent brief ringing, might be?

Best regards,
-- Al

Al,
It looks like it might be a reflection from your mic stand. You may need to invest $20 or so in a boom stand, attach the mic on the very end of the stand's horizontal arm, and extend the arm all the way forward. That's what DEQX recommends.

I have linked here to the same measurements for my speakers (midrange-treble only) for comparison.

These were taken outdoors and you can see a similar reflection from the mic (or maybe the grass surface), starting at 26ms.

Almarg, from your measurements I would initially window just before the reflection at 14ms and calibrate from there