Room correction - what device works best?

Re: mono subs, I can't help but wonder if a mono sub when being fed summed stereo input might actually find itself competing with channel signals and actually subtracting information in the process. IME, stereo subs have always sounded better than a mono sub when fed stereo signals. But I suppose their could be an exception to my experience that works differently?

05-11-15: Unsound
Al, I agree that the advantages the DEQX bring to the table might (probably) outweigh the down sampling issue, but in that sub $100 DVD players can decode (yes I realize that's all) the native higher sampling rates, it is still somewhat disconcerting that an item that can cost close to $5,000 can't do it all in the native higher sampling rates.

Hi Unsound,

Your reaction is natural and understandable, and as you indicated you recognize that the DEQX processing is much more extensive than what a DVD player has to do. But I think that my use of "much more extensive" understates it considerably. What I envision is that the mathematical computations that are involved in the digital signal processing the DEQX has to perform on the fly, fast enough to keep up with the music data, are HUMONGOUS. My understanding of it is that in real time it has to divide the spectrum into thousands of frequency segments, mathematically determine the contents of each of those segments by converting the series of data samples from the time domain to the frequency domain (that conversion involving a huge amount of mathematics), mathematically adjust the delays and amplitudes of the contents of each of those frequency segments in accordance with the speaker and room calibrations that have been established, as well as in accordance with any additional equalizations that have been programmed, and then put everything back together and convert it back to the time domain (again, a huge amount of mathematics), while digitally adjusting the volume and then converting the data to analog. I think it would not be unfair to characterize the processing a DVD player has to do as not much more than a drop in the ocean compared to that.

I'd imagine that if 24/192 processing could have been implemented in the PreMate which JA measured in a reasonable manner without drastically complicating the design, and/or delaying release of the design considerably (perhaps by lessening the extent to which that design could draw upon their previous design work), and/or making the unit much more expensive, DEQX would have done so.

I don't know, btw, if the design of the more recent HDP-5 which I am getting processes 24/192 as 24/192 or downsamples it similarly. But I'm not concerned either way.

Best regards,
-- Al

Al,

Yes, your speakers are truly of fine craftmanship. I've never heard them, but always found them very appealing from what I read.

Are you sure the DEQX can achieve time alignment among the drivers if you are to keep the passive crossovers in there? My understanding is the time alignment is done between pairs of channels, at the crossover points, through linear phase crossovers. Hence the need for actively amping. Maybe DEQX is different, but I think I did exchange with a user about this. At least on Acourate, I know the system can't time align if it only sees two channels as it can't delay part of the signal within a channel. This is why this decision has been so difficult to make. My system will need to change almost completely.

Al, as usual your points are well taken. The thing is, as I understand it, the <$500 stereo software (sans hardware!) from DIRAC can handle the hi rez stuff.

But is DIRAC computationally doing all that the DEQX is, or is it just a well-implemented digital EQ?