Try the coax first with an F to RCA adaptor. If you have excessive hum, the CAT5 wire makes an excellent balanced circuit. But you will then need either transformers or active balance transmitters and receivers.
Originally Posted by handsaw /t/1518225/cat-5-or-coax-for-subwoofer#post_24368242
I use coax for one of my subs in my HT and it is whisper quiet and sounds great.