I wouldn't count on that working well. The best place for two subs are where their in-room responses compliment each other for the flattest overall response. That isn't something that can really be done by ear. Sub crawl only works for one sub, and even then I wouldn't want to rely on that method of finding optimal placement without verifying it with measurement.
Agreed, but measurement is not. realistically, the world we live in!
Maybe here among "Audioholics", but among the population of AVR owners, I feel certain that measurement represents less than one percent!
On the question between 2 RSL's vs 1 Hsu, I think the bigger point is the RSL's are made for music (and will do a good job but not run nearly as deep/strong for HT special effects) and the Hsu is made for HT (and will do a good job, but not be quite as smooth for music).
IME a second sub has made a worthwhile improvement before measurement - although there is no question that measurement is the way to really do it right.
I was just surprised when you said a second sub is not beneficial unless you use measurement to set it up!
Quite honestly, when I have added a second sub, the room layouts only allowed for 3 or 4 options of where to add the second sub, so instead of doing the crawl, I just used trial and error to see which yielded the best result. I was probably lucky, but I have not heard the second sub make things worse!
Maybe it is not so important as I think, but before XT 32 (which delay matches the second sub to the first prior to EQ),I ruled out having one sub near and another far so as to try to maintain the most accurate attacks and delays. That limited my placement options more than maybe I should have?
What are your thoughts on one near and one far without the means to sync them for the listening position?
On the one hand, the last thing I want to do is give up some of the Accruacy of attack and add overhang from having one sub with more delay than the other! OTOH, when I listen to the sound of the subs by themselves, there is
nothing that sounds like a "crisp attack"! The perceived precision of the attacks seems to all be from higher frequency content!