Is DEQX a game changer?

Thanks blang.  That's a terrific article, I had not scene it.  I am currently attempting to learn everything I can about speakers and acoustics prior to pulling the trigger on a DEQX (now more "when" than "if").  I'm slowly working my way through the dense but brilliant, Master Handbook of Acoustics.

Ozzy, I think most users of big speakers like you and me are not doing measurements outside. Even taking indoor measurements, the improvement I heard was pretty drastic

Ozzy, looking at the photos of your setup and room in your system description thread I suspect that you would want to do something along the lines of what I did for the speaker calibration measurements. Namely moving the speakers to the center of the room for the measurements (one at a time, of course). And perhaps considering doing as I did in placing large sound absorbent panels against the nearest reflective surfaces (e.g. the side walls and the floor), when the measurements are performed.

In my case the resulting impulse response measurements were not nearly as "clean" as, for example, the results linked to earlier in the thread by Andrew (Drewan77), which he obtained by measuring outdoors. That in turn necessitated that I "window" the impulse response many milliseconds earlier than he did, which in turn resulted in me choosing to just implement speaker corrections at frequencies above 400 Hz, rather than down to 200 Hz which seems to be the optimal goal. (Lower frequencies are addressed in the room correction process, based on measurements at the listening position with the speakers in their normal positions).

So while I suspect that my results would have been at least a little better if I had measured outdoors, as I said in a post dated 12-2-2015 on the previous page of this thread:

Summing up my experience with the DEQX to this point, I would say that it has provided significant benefit to me as a result of its speaker calibration function, its room correction function, and as a preamp, and as a DAC. As I alluded to in an earlier post, speaker calibration seems to be especially beneficial in my system on recordings that are sonically mediocre, or worse. Bombaywalla had said some time ago, either in this thread or in the “Sloped Baffle” thread, that that can be expected to be a consequence of improvements in time coherence, and my experience with the DEQX appears to confirm that.

Also, regarding your own system, one thing I would wonder about is how the phase-related processing of your BSG QOL would interact with the timing corrections DEQX implements.

Finally, I should mention that for my critical sources I am using unbalanced analog inputs and outputs on my DEQX (as well as digital inputs), and so I have no meaningful knowledge of the sonics of its balanced analog inputs and outputs, one or both of which I suspect you might be using if you were to introduce a DEQX into your setup.

Regards,
-- Al

How would you add a better DAC to a DEQX preamp?  If it comes before the DEQX and goes into the analogue input, isn't the superior DAC's signal then reduced to the limits of the DEQX's DAC?  I read that you can use a superior DAC after the DEQX on the output side, but if you are using the crossover function (I would be) then you have the better DAC between the DEQX and the high frequency amp, but the DEQX DAC direct to the low frequency amp.  This does not seem right to me.  

This consideration is even greater if MQA rises to ubiquity.  Do you decode the MQA file in a DAC before the DEQX, then what happens to the decoded MQA signal when it goes through the new A/D and D/A processing in the DEQX?  Is the higher resolution preserved?