Time-alignment of Speakers
 

Has anyone used a time-alignment device (like a Rane AD22s) to delay the main speakers signal output enough to integrate a pair of "stereo" subs? If so, I would love to hear about your experience. Does it play well with an active cross-over? Does it degrade the sound?

I just did that with my system this past weekend. See my post under the thread called "My Afternoon with Barry Ober".

No degradation of the sound. My post on the other thread has a link to Barry's website and white papers he wrote on that subject.

I had already read that thread with quite a bit of interest. Barry attacked your time alignment issue by physically moving the subs. In my case I cannot physically move them, so I thought I would "delay" the mains instead.

The MEN220, which I am using now as only an active crossover, allows you to set the distance from the listener to adjust timing. You can adjust to your hearts content to set the relative timing of each speaker to the others. I don't have the elixir yet but I am getting closer getting my Fathom F113 v2 to merge well with my Strads.

Actually he changed the time alignment by changing the speaker distances in the digital preamp. He set all speakers to 7 feet (independent from their actual location to the listener) and all the subs to 19' also independent from actual distances. The subs were placed where they best matched the room physical frequencies independent from time alignment. Then he uses the phase of the sub to match the speakers to the subs. He explains the logic of doing this in the white papers posted on his website.

I used his technique to time align my third sub that is used exclusively for LFE in home theater operations. I set my other speakers to 9 feet and that sub to 21 feet to achieve what is, in effect, a 12 millisecond delay of the mains. The problem in the two channel mode is that I do not have a device like a MEN 220 or a Rane to delay the mains.

I've never tried any time alignment other than in car stereo, but when Jim Smith (Get Better Sound) came to my home and did his room play setup, we talked quite awhile about subwoofer placement and probably spent at least an hour and a half on it. He is very strongly supportive of placing stereo subs next to (or as close as possible) to your mains in order to minimize and time aligning issues, not to mention the closer they are to your mains, the more integrated they sound.

- Buck

But that doesn't help the inherent group delay of about 12.5 ms that Barry says all subs have...

For what it is worth my "stereo" subs are each immediately adjacent to their respective main speakers, are elevated 8.5 inches off the floor and are integrated via an active cross-over. I have acoustically treated the room such that I have a flat frequency response and a completely flat RTA response (decay time). I was thrilled with the sound right up until I cured the propagation delay in my LFE sub using Barry Oberman's method. Now I am wondering if I can also cure the propagation delay in my "stereo" subs. Moving my subs closer to me is not an option because I would be sitting on them. Moving them elsewhere to cure room modes is unnecessary because I have otherwise cured that problem. The Rane will definitely delay the mains, but will it degrade the signal is my main question.