Is DEQX a game changer?

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.

That's a great response Bombaywalla. So, in the absence of owning a speaker that is time coherent/aligned ... like mine which are NOT, the next best solution is DEQX. IMO, I think the DEQX really tamed my speakers and my room.

One can drop all the money in the world into electronics, cables and so forth. But, IMO, I think time coherent/aligned speakers are the way to go ... PLUS, the room HAS TO BE RIGHT. My room sucks and I have no other options. The DEQX cleaned up a lot of my audio problems.

Another question is driver distortion: harmonic and intermodular. I wonder if the DEQX fixes those issues too. I suspect not. As an fyi, the Magico S5 is one of the lowest harmonic distortion speakers I recall ever seeing tested. I don't recall seeing any speaker tester report on IM distortion. I wonder if it can be tested??

See this link: http://www.soundstage.com/index.php?option=com_content&view=article&id=1043:nrc-measurements-magico-s5-loudspeakers&catid=77:loudspeaker-measurements&Itemid=153

DEQX claim that their algorythm time aligns all frequencies within a given measured speaker, even if this is a 2 or 3 way, regardless of the crossover order or even physical placement of drivers on a flat or stepped baffle (measured at once - not so if a sub is then manually added for instance. That requires the manual 'best compromise' time alignment I have previously mentioned)

Therefore it is my understanding that Bruces' speakers have been time and phase aligned during measurement and calibration - within the limits of the microphone and the accuracy of the measuring environment but including the inbuilt passive crossovers

My reply relates to DEQX digital time alignment and not speakers that are physically aligned via the baffle and containing passive crossovers. Of course Bombaywalla is correct about that and the impact of the crossover order

Al/Andrew/Bombaywalla ... any thoughts about the impact (if any) DEQX has on driver distortion? My guess is that driver distortion is more a function of crossover and driver design and build quality itself. And that it is outside the realm of the DEQX to correct such deficiencies.

Just an fyi: Here's some bench test measurements of my Paradigm S8s (an earlier version #2): http://www.hometheaterhifi.com/surround-sound-speaker-systems/surround-sound-speaker-systems-reviews/a-secrets-speaker-system-review/page-4-the-paradigm-reference-signatures-on-the-bench.html

Not bad ... at least in the opinion of the reviewer.

My S8s (v3) use the same tweeter and mid drivers. The woofers and x-over were upgraded. Nevertheless, I assume the distortion specs would be about the same as those reported for the V2.

Even still ... compare the Magico S5s in my post above. Almost vanishingly low distortion specs. I suppose the real Q is whether we can hear the difference. Stated differently, assuming the Magico S5 and Paradigm S8 were DEQX corrected, how differently would they actually sound?

I gotta' believe that a 500 Hz test signal produced by the Magico sounds exactly like a 500 Hz test signal produced by the Paradigm S8. The real Q is how do the two speakers make music after being DEQX corrected???

Thank you for the kind works Bifwynne.

Yes, correct - for those who cannot & will not buy time-coherent speakers DEQX is one answer to the problem. And, I believe the DEQX people were smart when they realized that the room acoustics play an imp part & they incl room correction as well. I think we can safely say that 99% of the people live in homes where the room sucks! Does that mean these people cannot have good sounding playback systems? No, they surely can with room correction - either passive (tube traps) or active (PARC, DEQX, Lingdorf, etc).

Re. DEQX taking into account driver distortion - I think DEQX does that already. You put a mic in front of the speaker & measure. DEQX sees distortion. It does not itemize the distortion - X% from x-over, Y% from drivers, Z% from cabinet, A% from room. How does it know where the distortion is coming from? To it distortion is distortion. When it does a correction for the speaker is lumps all the distortion into one number & tries its best to fully correct it. Then, I believe, you go to the next step & do room correction with the mic at your listening position. And, this 2nd part takes out the other big contributor.

So, as you are playing music, the driver is still distortion (as it always did) but the DEQX correction curve has an inverse function to straighten this out. So, I believe that driver distortion is included to whatever extent the measuring mic can pick-up & whatever is the correction capacity of DEQX.
I'd be interested in others' comments too. Thanks.