Advice on sub and hookup for Martin Logan Ethos

I own a pair of Martin Logan Ethos speakers, bottom end 34Hz ±3dB and I'm thinking of adding a subwoofer to get down to closer to 24HZ.

a. Suggestions on best match for a subwoofer that gives most placement options ( to the side)?

b. Best way to hook up. (my concern is running speaker cables to subwoofer and and then back to main amp may degrade signal)

Hi Cdc2, You can get a REL and hook it up to the outputs of your AMP! Using the SPKON connection cable the AMP dosen't see this at all, having the signal off the main amp will give seamless integration with the main speakers. You can also get a Much better cable (than the stock one) for the REL at its the SPKON cable for the REL If you can find a used Britania series REL B2 or B3 Buy it! REL Acoustics..Hand made in the UK and Imported by Sumiko.For correct bass the REL should be in 1 of the corners.