Dual or single subwoofers?

You may be able to do it...although it is not recommended.

Corners have advantages in that they will increase your bass by about 6 db....so put the subs very close indeed.

Corner placement is definitely not recommended with speakers due to cancellations from wall reflections, which will make holes in the freq. reponse from 150 to 500 Hz (up to 20 db in some cases).

However, as long as you have your sub set with at least 12 db per octave filtering and a low corner frequency like 50 to 60 Hz ....then you can minimize this cancellation problem by limiting those higher bass frequencies from the sub and leaving your speakers (hopefully better placed) to fulfill that job.

Standing waves may be highly excited in this corner sub position too....so you may need to mess around with notch filters from your DSP.....much more than you would if the sub was placed one third of the way into the room.

Of course, with two subs, you could try and get clever and play with phase to get optimum configuration for the room...

The possibilities are endless but chances are you may be dissappointed with the results...and forever fiddling/tweaking.

I use two subs (Linn AV-5150) on my 2 channel system and love the results. When I got the first one and used it in a mono configuration (L & R signal blended internally) it didn´t sounded right. Then I got a second one and used them in stereo configuration and the system just sounds great. Hector

According to research by Harmon Kardon if you use two subs it is best to place them in the middle of two walls which are perpendicular to each other, rather than two corners. You will have to experiment.

I am definately in favor of using 2 subs but what might be a better solution for you would be to keep your Rel and add a Velodyne SMS-1 EQ. Now that I think of it though most Rel's have a different connection configuration so I am not sure if it would work with the SMS-1. You definately want to look into it though.

For $600 it is the biggest improvement I have personally made in my system as far as bass is concerned. The bass in movie soundtracks is downright scary and the SMS-1 has 6 different presets so you can use it with music as well. I personally never used my subs when playing music as my mains are full range but with the SMS-1 in Jazz mode my subs blend beautifully with my mains like never before.

Shadorne is right when he says "The possibilities are endless but chances are you may be dissappointed with the results...and forever fiddling/tweaking" but with the SMS-1 it really helps put an end to your tweaking for good.

If the connection options with your REL allow integrating the SMS-1 into your system you owe it to yourself to give it a try.

PS: On the # of subs I use 3 and they are all connected and corrected by the SMS-1.