I have two way towers and I notice a distinct improvement in imaging and instrument focus from adding two subs for discreet L&R output. I don’t why that result would be different for a full range tower but stranger things have happened.
One unlikely thing did happen, the addition of the dedicated low cabs brought a new depth and spread to the recordings reverb, I really notice that on back ground vocals and percussion. I find this superior in every way to a mono sub.

I'm using two old MK sealed subs with my SpeakerLab corner horns.  I just added the second one and  I can hear what Mr. Guttenberg is talking about. There are times when it sounds unreal.  Unfortunately I cant find a consistent setting for the subs.  It's difficult to match subs with really efficient speakers as the volume slopes of the subs and the speakers don't match. The other issue is the subs seem to be canceling out each other where they're placed in the room.  I've moved them out away from the wall and dropped the crossover frequencies but it varies so much from recording to recording that what sounds good on one recording overpowers the room on another.  A pain for sure but it sure sounds good the rare times I get it right.

I'm going to try stacking them and see if that helps.  Any suggestions welcome.

And here's the subwoofer, crossed at maybe 30hz but I know the silkscreen numbers are just a suggestion, you can see that Klipsch does not believe in a steep roll off:

Hello friends...
I am considering the purchase of dual subs, and need help from the Decware family...

My room is open concept @ a very caverness 32’ wide, 25’ deep with vaulted ceiling approximately 13’ at the peak (LR, dining, foyer, kitchen).

The system I have (listed in my tag line) was fantastic in the LR of our previous residence, but since the move into the current location, the bass gets swallowed up in the larger space leaving the overall balance quite poor.

I am probably 70% music to 30% movie, and prefer the dual sub route to maintain soundstage balance and hopefully bring back the joy of music listening.

So far, I have selected the sealed over ported model and have considered
a pair of either the SVS SB-3000 or Rel T/9x. I believe the pair of SVS’s would be sufficient and are better suited for both music and movies in this large space, but my fear is that the Rel’s may not. The Rel T/9x reviews sound great for music (which is most appealing to me) but may lack the horsepower in the large space.

Thank you so much in advance for taking the time to read this, and I look forward to any feedback

-Mark

I have an old Home Theater Velodyne active sub that I use with my ERR tower speakers.  It has a 10” front firing and a 12” down firing and it is a beast!!  I have them crossed over just right at the point where my tower speakers fall off and I keep the volume level fairly low.  I want my main speakers to do the majority of the work and my sub to take care of only the low frequencies that my towers cannot produce. I think I keep them crossed over at like 30 Hz.  

My living room is like 32x30 with 18 foot vaulted ceilings and an open concept floor plan that spills out into my kitchen and dining room…so I am a dealing a large space as well.  

Two things I can recommend once you get your subs… play around with the sub’s location by moving it around the room to find it’s best location where it sounds the best.  The front corner is theoretically not the best spot in general.  Also…take the subwoofer off the floor and place it on a pedestal.  Mine is about 1 ft. off the floor.  

Dom

4Krow:"The point is to know where to start by using the measurement system in the first place. And yes, trust your ears. After all in the end it is about you and not some microphone."

Rivieraranch:"Just keep moving it around and tuning it until it sounds right. I did that and it came out real well. Turns out that it is in the right rear of the listening position."

We also have a room very similar~ Dominick: "My living room is like 32x30 with 18 foot vaulted ceilings and an open concept floor plan that spills out into my kitchen and dining room…so I am a dealing a large space as well.~~Two things I can recommend once you get your subs… play around with the sub’s location by moving it around the room to find it’s best location where it sounds the best."~~  [smiley=icqlite20.png]  

We have a pair of Klipsch Chorus 2's in a room very similar to Dominicks..About the same dimensions, large open floor with high 12' cathedral ceiling in middle. Ceiling starts at 8 feet either end. Two very large rugs in center and left side at dining.  Kitchen and dining to the left side. Rest of house has 8 foot ceilings.  It took me months to get the subs sounding like I like them to. Small adjustments over time. Including phase and levels. Phase mostly for two toward rear of room. Front corner one is at 0. If they seem sort of loud and or localized..turn them down a bit at a time. I started with two..and now have three. General word on the street is go in two's, but, 3 are working for me fine now. Your going to need to play with location a lot! Your ears in your room are all that matter. ~Mike  [smiley=beer.gif]

I have dual subs in my shop (listening room) and they sound better when they are both in mono, rather than stereo.  Don't forget to at least try them in mono...it might surprise you.

Dan

Have you contacted REL? You can give them the specifics of your system and the exact measurement of your room and adjacent layout, and they can recommend a solution that will work optimally for your situation. They actually prefer their customers do this before purchasing.