Group delay in subwoofers

Jc4659, I spent the last 4 days dealing with sub setup and group delay. My experience was not to use the setup info from the manufacturer.  Did that and it was a waste of time. I did a lot of research and followed the advice given by soundoctor.com and referenced other sources. The first and very important step is proper placement within the environment.  Once I found the sweet spot I again followed manufacturers instruction and again wasted my time. I then followed the instruction by soundoctor.com and finally hit the nail and I'm now loving it. Enjoyed my fully properly integrated sub tonight from 5 to 7 pm. All the tools required were a tape measure, SPL meter and muscle power. Soundoctor.com information rocked my world.

@gillatgh I have the sound Doctor cd with all the low frequencies and have used the out of phase method to find the null zones.  Unfortunately the best location is unacceptable to my wife.  Like I said, it's all about compromises.  Congrats on dialing it in.  You know when it's right.

For sure compromises are part of the game. The trick is to get it as close as possible to the sweet spot. I was fortunate to find an acceptable sweet spot which also was aesthetically acceptable but it certainly is not dead on but within the zone. The result may not be the best it could be but it's close enough for awesome rendition. My point really was that manufacturer instruction will not get you there while soundoctor.com information was free and very informative. That and their links to relevant info were invaluable to me

@bdp24 Can you tell us more about the continuously-variable phase control. I researched a DIY phase control solution (not just a 180 switch) awhile back and couldn’t find anything on it. I actually convinced myself that the continuously-variable dials I see on subs aren’t doing what they say they do. Haha! So... they do exist? How in the heck do they work?

Subwoofer should be close to the plane of the front L and R speakers.

8 feet is likely going to begin to cause some integration issues with main speakers simply because that puts the subwoofer much closer to the listening area (creating uneven sound and making stereo subwoofers a better option)

Group delay is important but this comes from ported subwoofers. DSP is not a significant delay at subwoofer frequencies.

if the subwoofer is sealed then you really don’t need to worry at all

If either your speakers or the subwoofer are ported then you likely will get best results following THX guidelines - sharp cut off filters at 80Hz and therefore minimize speaker and subwoofer overlap. Ports are what usually causes the largest group delays.

Finally your DSP should be able to correct for speaker and subwoofer distances to the listener so that everything is coherent at the listening area.