Is DEQX a game changer?

Sounds like a good idea to use acoustical absorbing devices to reduce the magnitude of reflected sound that would reach the calibration microphone otherwise. Would seem to be a positive step towards reducing effects of room acoustics.

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

Apologies for the delay in response here guys as I am in Europe and there is obviously a time difference

Answering the question about windowing - an indoor measurement is not as clear as one taken anechoically and those sent by Bruce are rather like that although it is not bad by any means. My own measurements are crystal clear, a strong main impulse followed by a virtually flat line with four 'tiny' fading reflections. What you are supposed to do is window just before the first apparent reflection (26ms vs 26.2ms in my case). Larry has windowed at 24ms although I see a fairly strong reflection at 19.6ms so this will be included in the calibration

Regarding room correction - I may be lucky in that my music room has solid walls and floor and I am able to keep speakers and chair well away from walls using the so called 'golden formula'. Using two subs has also helped so that I need minimal room equalisation: max - 1.5dB at just 33.4hz & 36.7hz and further very slight equalisation below 219hz - bass is very tight, dynamic and uncoloured (much less eq than Larry has used in Bruces' room which is in a range of -3.7 to +4.1dB between 116hz and 1469hz)

As for time alignment - I originally used DEQXperts from the manufacturers in Australia and also the Netherlands. They taught me a lot but I was never told to use unequal timing for main speakers which is what Larry has done (6.60ms LH main speaker, 6.68ms RH). Maybe it's something to do with Bruces' room or he is seated off centre? In any case time alignment needs to be checked by ear and I align the matched peaks of the subs to the first rise of the main speakers rather than the first impulse peak as Larry has done. I have listened to both arrangements and in my setup aligning to the rise rather than peak gives a natural and seamless bass response where I can clearly hear each instrument individually and especially the realistic 'growl' of a bass guitar from within the lowest frequencies

And for Subs - yes it is good that they take over the lower frequencies so that all amps and driver sets have a narrower band to work with (ie cleaner, clearer), in my case at 100hz with a 48dB Linkwitz-Riley crossover. Larry has used 120hz, 24dB and Butterworth so this may be related to the combination of speakers and subs that Bruce uses. I found that my subs (Miller & Kreisel plus B&W) sound slightly unnatural if I crossover above 100hz and at below this, my Open Baffles lose some attack

I must admit that I spent many months experimenting, taking advice, re calibrating and listening before I arrived at the optimum for my system so it all depends on how much time each of you can put into this. A DEQXpert (or another user like me) in a remote location can advise but only YOU know what you are listening to

With that in mind, I will mail Bruce and look at his latest measurements as suggested. It's a shame that this forum does not permit embedded illustrations as I could explain this so much better by screenshots of our two setups

Here to help if I can....

thanks for the clarification Almarg. I forgot that DEQX also does room correction. yes, makes sense that the mic is at the listening pos for room corr.

Well, hearing one vote in favor and none opposed I've decided to order the large acoustic panels I referenced in my previous post, for purposes of shielding the mic from reflections during the speaker calibration measurements.

The one slight concern I've had about doing that is the possibility that the panels might in themselves cause some low level reflections, that would arrive at the mic a millisecond or two after the direct sound. But hopefully not, and even if that were to occur to some small degree I'm thinking it could probably be minimized by some re-positioning of the panels. And although I would normally be hesitant to spend $340 on something that may end up being used only once, I'm guessing that the investment will provide benefits that are essentially permanent.

Andrew (Drewan77), thanks again for your always valuable perspectives. I find it interesting and somewhat surprising that they extended the window of Bruce's speaker calibration as far out as 24 ms (about 17 or 18 ms after the direct arrival), given that significant reflections occurred earlier. Makes me a bit less worried about the reflections I may end up with.

Best regards,
-- Al