How to Add a Sub on a 2 Channel System?

Hi,
I'm using maggie 3.6's biwired with monoblocks, what is the best way to add a sub in this configuration?
Also, is it best to leave the speakers running full range?
Do I need an active x-over with this setup, or can a sub be added keeping my existing maggie x-overs?

Thanks

Rooze

Rooze, I think it depends on the design of your amps, but REL recommends two subs with most bridged mono setups connected from the speaker terminals on the amp to the high level inputs on the sub, one sub on each amp. I'm assuming you have one amp on each speaker now. In that case, no need for a separate active XO and it would not go through the maggie xo either. You would still send the full range signal to the speakers and the subs would be set to fill in the lower frequencies where the mains roll off.

You may need to contact the amp manufacturer to get their recommendations, or someone here may know if you provide more specific information.

Thanks Eagle, the amps are Cary V12i Mono's. Using two subs, would I basically run each sub in mono, just taking another speaker cable from each amp to the single sub?....The cary's have taps for 4 and 8 ohm, I'm using the 8 ohm tap as it sounds better. Could I feed a single sub off the 4 ohm tap or is it better to keep it on the 8 ohm?
I also use a ARC LS15 that has another set of balanced outputs available and also a set of unbalanced. Would it be sonically acceptable to drive a single sub direct from the preamp?...Cost is becoming an issue, so one sub then a second in a couple months would be better provided that I don't upset the balance with only using one sub.
Thanks
Rooze

The REL sub I have is the Stadium III. It came with a high level, 30' cable that has three wires and a Neutrik Speakon connector for the sub. With my single amp, I connect a wire to each channel on the + terminals and the remaining wire to the right channel - terminal. The Speakon connector goes to the high level unbalanced input on the sub. With bridged monos, the REL manual says to connect one sub to each amp on the + & - terminals and the third to the amp ground. The Speakon connects to the high level balanced input on each sub. That would help keep the cost down.

You should ask Sumiko , the REL US distributor, for suggestions on running a single sub with mono amps.
You do have the option of using the line inputs on a single sub, but REL stresses the benefits of the high level connections so I would try to do that first.

Some people use two Strata subs and report excellent results.

Thanks again Eagle