Is DEQX a game changer?

Al, sorry I didn't respond last night to your message. My internet was down until after 11pm. You asked:

"When the DEQXpert people calibrated your speakers, how far did they end up placing the microphone from them?"

My recollection was about 36 inches as measured from the tweeter.

"And if you know, how many milliseconds after the direct sound arrivals did they place the point at which subsequent arrivals were windowed out?'

Don't remember ... sorry.

Al, what I do remember is that Larry, the DEXPert, asked me to take precise measurements of the speaker height, including the space between the drivers. In addition, Larry asked me to take precise room H,L and W measurements, including the distance the speakers were placed from the front wall and the distance my listening position was from the back wall. He also asked to me to position the mic at the precise spot of my ears. No kidding!!

Please keep us informed of your progress. And have fun!! :)

He also asked to me to position the mic at the precise spot of my ears. No kidding!!

yup, no kidding! this is where you found the drivers to integrate best & the DEQXpert leveraged off that info to make the measurements. Any closer & you would have had the similar timing errors that Almarg wrote about. Makes sense....

Thanks everyone for the good responses.

I guess part of the answer to the issue I described, about the possibility of correcting a non-problem in the case of large speakers that can't be measured from an optimal distance due to reflection constraints, is that under such conditions speaker corrections would (or at least should, per Nyal's (AcousticFrontier's) recommendations) be performed only at frequencies above the point where the woofer(s) are likely to be significantly rolled off. For example, the crossover point of the woofers in Bruce's (Bifwynne's) speakers are indicated as being at 230 Hz, with a 12 db/octave rolloff above that point. (I don't know what the corresponding figures are for my speakers, as they aren't published and haven't been measured as far as I am aware).

Bombaywalla, thanks for your inputs as well. As you aptly stated, there are always tradeoffs. Re your last post, though, undoubtedly the measurement they had Bruce perform at the listening position was for room correction, not speaker correction, room correction generally being done with DEQX only at frequencies below around 200 Hz or so, where room effects predominate. Speaker correction, including time alignment, would have been performed at the 36 inch distance he mentioned, and only at higher frequencies as I indicated.

On another note, would anyone have any comments on the possibility of surrounding the measurement microphone during the close-up speaker measurements with two of these (four panels total, surrounding the mic on three sides). Acoustic specs are here, and look impressive. Or, alternatively, a mic baffle such as this one, which is apparently made of the same material as the large panels.

Best regards,
-- Al

Bruce previously sent me his files and Larry windowed at 24ms and 98% smoothing. My own outdoor measurements are windowed at 26ms & 0% smoothing because measuring 'anechoically', the plots are clear and have almost no reflections or impulses other than the speaker itself - it's an almost flat line until a clear and tiny reflection at 26.2ms which repeats every 3ms until fading away at 36ms

However the windowing I quote is based on reflections made by Bruces' setup and will be different for yours. To be safe, I would suggest you try to look for a clear smoothish area after the main impulse and before the first obvious reflection. However, that may be difficult with a somewhat confused indoor measurement

Drewan ... in your opinion, did Larry "time align" tame my beasts pretty well? Ditto room correction?? What is the significance of "windowing at 24 ms"?? What is better ... a long or short ms time frame? Or is the question a non sequitur??