Is DEQX a game changer?

Excellent post by Bruce (Bifwynne), IMO. Like Cerrot, in general I too am biased in favor of minimizing what is in the signal path. But digital signal processing can do amazing things these days, that often are either not possible in the analog domain, or that cannot be achieved in the analog domain without significant tradeoffs. In this case, those tradeoffs begin with the fact that limiting one's choice of speakers to those that are time coherent rules out most of the speakers that are on the market. And for various reasons, electrostatics such as Cerrot uses are not for everyone.

In any event, putting its time correction feature aside, DEQX seems like a promising candidate in its price range just for its room correction, preamp, and DAC capabilities.

One minor correction to Bruce's post: An Nth order crossover rolls off at 6N db/octave, so 3rd order = 18 db/octave.

Best regards,
-- Al

Thanks for the correction Al. A stupid waste of time on my part -- I checked WIKI and right you are.

Btw, Cerrot, I checked your system ... absolutely gorgeous room and STATs. Are the ESL elements full range or is there a conventional sub to fill in the bottom?? If the latter, at what frequency do the ESLs cross over?

Bifwynne,

I totally agree with you. The problem is passive crossovers. This is why I went with hybrid stats and an active crossover. I do believe the way to eliminate the time allignment issue (not talking about the sloped baffle issue, which I am familiar and have been discussing for 30 years...) is an active crossover (or single driver, obviously). In any event, I do feel the DEQX is just an attempt of a solution for an already flawed system. Remember, time allignment is not the only problem. Impedence is the issue as well. Your amp sees your speakers crossover, not your speaker.

Bifwynne, just read your 2nd post and reponding. Thank you for the compliment. The speakers are hybrid electrostatics, with 10 inch aluminum drivers in a transmisssion line enclosure on the botton of the stat panel. I crossover at 172 Hz, with a 48 dB/octave slopes, Linkwitz-Riley filter. Each (both panels and both woofers) are fed by a pair of Magtehs. There was minor fusing with the bass signal to line it up with panel to get a purely seamless 3 demensional sound.

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.