Is DEQX a game changer?

I've been trying to arrange a DEQX home audition. Came close to setting something up tomorrow, but vacation schedules got in the way. Hopefully, soon after Labor Day.

Bob, if you read through the Sloped Baffle thread, you might get a better sense of what the DEQX device can do. The beating heart in NOT room equalization ... it is time coherence correction.

Most speakers on the market are not time coherent. They may be phase coherent at the x-over points, but not time coherent. The DEQX measures actual time incoherence of one's speakers and makes corrections by delaying various slices of the sonic spectrum to align the output of the various drivers. Room EQ is just an added plus.

If you look at most of the Stereophile speaker reviews, one of John Atkinson's tests involves a time coherence analysis. What you see in most cases is the tweeter reacting first, then the mid driver, followed up by the woofer. Sometimes, one or more drivers are wired in reverse polarity to achieve phase coherence at the x-over points.

So in the more usual case, the DEQX will slice up the sonic output of the source signal into 4000 segments. Then, using a very sophisticated chip, the DEQX will delay (up to 10 micro seconds) the various segments in order to achieve time coherency. Since the tweeters generally respond before woofer, the sonic spectrum covered by the tweeter may be time delayed vis a vis the woofer. The same approach is applied with the mid driver.

Back to the Sloped Baffle thread -- Roy Johnson of Green Mountain Audio has posted some great articles that explain why most speakers are not time coherent, the impact on the summed wave form, and how he attempts to effect corrections. In most cases, the fix, or his fix, is to use 1st order x-overs and to recess the tweeter and mid driver vis a vis the woofer so that the voice coils of each driver are perfectly aligned in vertical space.

The DEQX does this electronically.

So, I'll report back as soon as I can arrange my home audition.

@Bob -- just wait until I home audition the DEQX. As seems to be the case with a great many audio issues, there is a divergence of opinion.

Yes ... on the hand, the time coherence opponents say that most people can't tell the difference between a time coherent speaker and one that is not time coherent. The naysayers may add that like all engineering problems, trade off are made. Perhaps there is greater flexibility in driver selection in the time incoherent space.

OTOH, folks like Bombaywalla, Roy Johnston, Rich Vandersteen, and the late Jim Thiel urge us fence sitters to drink the Kool-Aid. And as stated above, Roy has written some really good white papers that explain time coherence and why it so important.

At this point ... I am still sitting on the fence and will continue to do so until the US DEQX sale reps sets me up with a home demo.

So ... to my fellow fence sitters, hopefully sometime after Labor Day I will be able to post my reactions.

Cheers

BIF

Looking forward to your follow up Bif. (Lucky you)

08-21-14: Bob_reynolds
Bruce, thanks for the additional insight. Is there a reason that most speakers on the market are not time coherent? I think so -- it's way down on the list for impacting sonics. Meadowlark claimed to be in the time coherent school and published a nice looking triangle graph. They didn't sound time coherent to me, i.e., I couldn't tell that they were or weren't. Things that have a large impact on frequency response like room correction will definitely be audible. So, time coherence may be DEQX's selling point, but that won't be reason enough for me to be interested.

Bob, you couldn't be more wrong about time-coherence & it's importance to music playback.
Most speaker designers simply do not understand the math & physics to make a speaker time-coherent so they skip this part totally.
For the Meadowlarks you might have known how to set-up the speaker &/or what to listen for to ensure that you were seated in the right location to hear the time-coherence. Plus, guidance could have been poor from the manuf.

I would strongly urge you, as Al already has, to read that "Sloped Baffle" thread he provided the link to & search for DEQX & read other things about time-coherence. I believe it will be educational to you.

BTW, there is atleast one member in that thread, lewinskih01, who is using DEQX & has found it to be transformational in his system - it made his speakers trend more towards the time-coherence paradigm than before & he is pleased with the results (so he wrote).
whatever makes your speakers more time-coherent will make your listening even better.

And, if your system pix are the latest, I see that you are doing atleast 1 aspect of the time-coherence thing: time-alignment of drivers. You have your tweeters pointed out on both channels. This makes the path length from the tweeter a bit longer compared to the woofer which has the effect of time-aligning the acoustical centers of those 2 drivers. That helps to intergrate the sound of the drivers at the listening position.
So, if this is any clue to me, you are going to like a time-coherent speaker even more.
That "sloped baffle" thread is a good one to read. I 3rd Almarg & Bifwynne on your reading that thread.....