Subwoofer recommendation and wisdom

@mswale    I don't agree with any sub crawl suggestions. It's hard to localize bass below 40Hz. A mic does a better job.

When performing the crawl or stroll within the room you're listening for the standing bass wave excited by the extra low frequency typically near a rooms boundary. 

Exactly what make and model subwoofer have you placed in the listening position to preform this task?

Sub-bass woofers output rated at -6dB@xxHz typically roll off before exciting the rooms standing waves resulting in the crawl a futile exercise.

This is not a passing phase.
 

What is most important with Rel’s of any size is checking phase. The phase switch can be set at 0 or 180. My first humble-rumble set of Rel Quakes, even back in 2006 went far deeper when set out of phase.

Remember this simple check and never assume anything. The two Rel T9i’s l use now with the Hi level input are correct with the 0 degree (in phase) position.

@m-db The crawl is outdated and likely not something Dirac and Audyssey would recommend. One crawl does not tell you whether you are far or near target like a mic and it takes many crawls. It's just a yes/no at best. It does not tell you the frequency response, peaks and everything between. It also does not allow for multi-sub integration. You would be done sooner and get more optimal results pushing the subs using sliders and measuring. Also you won't damage your back and the couch dropping a few hundred pounds on it. Two 260lbs B&W speakers, two 60lbs B&W DB4S sub, one 180lbs SVS PB16 sub.

4 subs versus no subs