Open Letter To REL, SVS, Hsu, etc., et al

@audioguy85, Very few speakers have useful output below 40 Hz. Anybody can set up a sub for home theater. It takes a real hero to get one set up for an audio system but, doable. I cheat. I let a computer do it for me. Certain speakers like one way ESLs clean up dramatically when you take the bass away from them but all speakers clean up to some degree.
@james_edward , all the test tones in the world won't help you if the instructions supplied with the sub are out to lunch. The manufacturers know they will not be able to sell subs if they are complicated and if there are add on costs. So, they settle for low pass only crossovers and adding the sub in under the main speakers settling for significant overlap and phasing issues that are hard to overcome without more complex measurement and digital manipulation. Even if you could get the speakers in phase the subwoofers will be starting one to two cycles late. To get the main speakers and subs to start at the same time you have to delay the main speakers and this can only be done digitally. There are ways to overcome this but most rooms and set ups won't allow for it. 
 The DEQX Premate has a good bass management system. Check it out. 

Speakermaster, you need to impulse test each individual speaker and time the impulse to the listening position. An SPL meter can not do this.
You can adjust phase by looking for the loudest volume at the crossover point but you can not time the speakers this way. You can also not determine with any accuracy the frequency response of the various drivers. You have no way of adjusting various factors for the flattest frequency response. You can buy a calibrated microphone and programming to do this if you have a computer hooked up to your system. 

Hsu does include a CD with test tones for bass with their subs.

If you are looking for other CDs to help, Alpine Electronics (the old school car audio folks) produced some great CDs in the 90s with music and test tones.

Two to look for are: Disc Drive and Highway One.
Highway One has some of the cleanest and most dynamic musical test tracks I have ever heard along with many test tones. It is a fabulous demo CD if you can find one. It was made for the Australian market, so tough to find in the states. Subs are fun and rewarding once dialed in. Good luck!

I purchased a pair of REL S2 SHO subwoofers and I still don't know if I have them set up right.

With the rudimentary REL controls, one would have to be very lucky to integrate properly for 2ch music.

It's almost a certainty they might need placement in a non-WAF location

I’ve had subs since I can remember , and trust my ear to set one up properly. I had bi-amped Altecs (which were not technically “audiophile”), but dual sealed cabs were great.

Then came a decent ADS sub (aquired when I sold ADS home and mobile gear.
Today it’s a Rel T9i which is superb and came with excellent docs on setup.
 😜😂😂