why go against REL setup recommendation?

Once I get a subwoofer properly integrated for 2 channel audio it will actually sound good placed almost anywhere in the room, simply because I can't listen to the just the subwoofer. It is blended perfectly into the music. It does not call attention to itself one single bit.

I can only "hear it" when I forget to turn it on, and start to wonder why the music sounds a little flat today.

This was Richard E. Lord's (aka REL) goal in designing the ST series. If you like to listen to bass, I agree, save your money and get a cheaper REL Q Series sub, which is a more typical subwoofer design, but still very musical in its own right. Or choose another brand.

I have a REL sub and it did not work in the corner of my room- boomy wobbly bass. Ultimately, the sub worked best when it was placed on the same plane as the speakers.

I agree with the above post on not having enough sub for the room and using corner placement as a substitute is not a good solution.

Once you have enough output, though, you will most likely get better bass using two good subs versus one really good sub. Most people do not understand that it is not always about output, but rather equalized sound pressure in the room. Yes, I've heard all the theories about bass not being directional, but to my ears stereo subs work better.

The Classic way of placing a Sub is on his Knees... just kidding.

Best way for me is placing the sub in my listening spot and crawling around the room, looking for the most clear and precise sub bass reproduction. That is where you place your Subwoofer.

The most useful recommendation from REL is the level...if you do stick one in a corner just don't crank it up. The "sub bass" description of RELs is silly...they invented this term for reasons unknown as these things work EXACTLY like every other sub with adjustable crossover points. 40hz? 120hz? Whatever...silly...I use 2 RELs at around 58hz or so to blend with a pair of Heresy IIIs and one (a down-firing Q108MKII) is about 2 feet behind the left main speaker in a little corner created by a gas fireplace, and the other (Q150e front firing) is moveable near the right speaker...I move it a little away from a corner because I can...I slide it around (vinyl "spikes" don’t scratch the wood floor) based on what I’m listening to, or my mood, or relative humidity (which is the humidity of my relatives). Crawling around the room has nothing to do with how your rig sounds in the "sweet spot," so listen from there unless you like to hear things while crouched in the corner, and since all recordings are a little different, turn the subs up and down a little when needed (I stuck "chicken head" knobs on the High Level pots for this). There ya go!

I also use a REL with Heresy III and they sound great together.   You can NOT use RELs Neutrik connector wth fully differential balanced amps like ATI or many oof the amps they OEM for because they too are fully balanced.    

I have a pair of PP mono tube amps and I can't get a diffinitive answer if connecting the REL cable is safe or will deliver both channels so I have just used my Veledyne SMS 1 which I prefer because I can experiment with low pass, slope, and manual or auto EQ.    I have the R-305, it older but still sounds great.  I have it hooked to the LFE so the sub is not using it's x-over

The biggest improvement I can suggest is a isloation platform like the Auralex Sub Dude.    Unbelievable improvement in a room with hardwood .