Is DEQX a game changer?

Cerrot -- double agree with your next to last post. Fortunately, my amp can handle my speaker's wacko impedance and phase angle curves, especially since I am crossing over the sub and woofers at 120 Hz. A lot of watts are saved because a good part of the load is handled by the self powered sub. Also, my amp, an ARC Ref 150, has quite a bit of muscle in its own right.

And while some might quibble over whether their system is "flawed," I think a better way to see the picture is that design compromises have been made and time coherence is just one of the compromises. This is especially so when one considers that the "cost" of time coherence may involve ugly sloped speakers, some of which look like insects, and drivers that are being asked to make sound over a wider pass band. Plus, speaker placement can be finicky and I don't like listening to music with my head in a vice.

And my fix, the DEQX, while having its benefits has its costs, the least of which is NOT pecuniary, as well as adding another artifact to the signal path. Having said that, I think, but am not totally sure, that the added artifact factor may be minimal.

As I've alluded to earlier, on the one hand I worry that "after the fact corrections" might make difficult demands on drivers, etc., for which they weren't originally intended.
On the other hand, I wonder if these very same "after the fact corrections" were instead original design implementations they might be superior to the original way in which speakers were designed to achieve some of these performance parameters.
What ultimately arrives at our ears, regardless of how it got there, is really what counts.

In theory, adding additional processing into the signal path should have a negative effect. Maybe...but the benefits in my experience greatly outweigh any theoretical drawbacks and I only hear improvements. I certainly cannot detect any loss of transparency - in fact I have never had such a sense of real performers in a believable soundstage

Contributing to this thread has made me put a lot of thought into what it really is about DEQX that I find beneficial. So, in order of significance, this is the impact on MY system after using DEQX for two and a half years:

1. The ability to adjust almost everything on-the-fly whilst listening to music in your own room. - Irreplaceable, I could no longer own a system without this feature. Everything else was 'guesswork, trial & error'

2. Measuring & correcting non time-coherent speakers. Phase and timing is aligned at all frequencies, not just a 'theoretical' passover compromise - Huge impact

3. Time aligning subs - Huge impact, it is no longer possible to detect a crossover or any nulls or peaks, no matter what type of music is played

4. Ability to create crossovers at up to 72dB slopes and adjust crossover frequencies so amps & drivers operate in narrow & more efficient frequency bands, also the choice of different crossover types - Very big impact

5. Room correction - Reasonable impact (not so necessary when all the above are already dealt with anyway)

6. Preamp ability - Neutral... it seems to have no sonic signature I can detect. One more analogue input would be useful, that's all

7. Four presets selectable by remote control, each giving a slightly different adjustment to the lowest frequencies to compensate for thin or bass heavy albums - Not often used but very useful when necessary

8. DAC. Very, very good but slightly clinical - I can live without this

9. The ability to create and save further equalisation from the remote control (a huge number of presets) - Not used

Additionally:

- Ease of setup - logical but a lengthy process to do it properly. Automated widgets make a pretty good result quite easy and far simpler than any equivalent DSP I researched. Take the time to understand it and the results are fabulous

- Ease of use once understood - logical, practical and infinitely adjustable until 'perfect' at the listening seat

- Overall, the combination of 1-5 above makes the effect of your room an irrelevance and it no longer has any audible impact on the music you play. - therefore this equipment is irreplaceable (for me)

As I have said previously in this thread, please keep an open mind until you hear a fully corrected system. I was one of the biggest cynics out there until I decided to try it for myself

Drewan ... re your comment about the DEQX DAC. I've been comparing the ARC CD-8 fully operational using its onboard DAC to going sans CD-8 DAC directly to the DEQX DAC. In the latter case, the CD-8 is being used just as a transport AND I am not using my ARC Ref 5 SE pre.

Very, very close. The DEQX may have it over the CD-8 (with DAC)/Ref 5 combo .... but it is very close.

Btw, when comparing the DEQX with time and EQ correction engaged or not engaged, or the DEQX DAC (as described above), I use a Radio Shack SPL meter. I find that when the DEQX is engaged, the SPL output is about 1 to 1.5 db higher. I try to compensate to ensure I am comparing apples to apples.

And while some might quibble over whether their system is "flawed," I think a better way to see the picture is that design compromises have been made and time coherence is just one of the compromises. This is especially so when one considers that the "cost" of time coherence may involve ugly sloped speakers, some of which look like insects, and drivers that are being asked to make sound over a wider pass band. Plus, speaker placement can be finicky and I don't like listening to music with my head in a vice.

A few corrections, Bruce:
(1) time coherence/in-coherence in a speaker is NOT a design compromise - it's a design paradigm. Pretty much like Ralph of Atma-sphere deciding to manuf a voltage paradigm or power paradigm amplifier. Once the designer chooses the design paradigm then you can make design compromises (quality of components & other mechanical materials, etc).
(2) Drivers that are being asked to operate over a wider bandwidth in a 1st order x-over time-coherent speaker have been very carefully chosen such that these drivers have zero problems operating over that wider bandwidth. That is why most drivers on the market don't qualify. So, if the 1st order x-over time-coherent is correctly designed then the x-over frequencies will be such that these wider bandwidth capable drivers will have almost zero distortion.
(3) Speaker placement of 1st order x-over time-coherent speakers is NOT finicky & you do NOT need to put your head in a vice to listen to music. Speaker placement & listening placement have some special guidelines such as ensuring that your distance from the speakers is such that you give the sound from the various drivers to integrate & that you place you ear at the correct height off the floor. This is not unreasonable - you would do this for almost any other speaker. Yes, the sliding back/forth of the tweeter to get it correctly time-aligned to the listener's particular distance is a little bit of a trial & error thing but once again it's not unreasonable. The factory cannot set this tweeter position as different listeners listen at different distances & the distances can vary anywhere from 9'-15' depending on the speaker & room size. Once this setup is good/verified by the owner, you can shake you head like Stevie Wonder/Ray Charles or like Cerrot you can dance in your seat - sound from the 1st order x-over time-coherent will not vary....

You seem to be misguided on these few points &/or forgot that these points were discussed at length in the "Sloped Baffle" thread. Anyway, here they are again for your reading pleasure. :-) Hope that this clarifies & helps. Thanks.