Hello,
I say just get a female to female adapter and add another rca run. Placement is very important. You can extend the speakon cable since it is just a signal. Just so you understand I put one sub on each side of the left and rt speaker to add or enhance the sound of my music. I then just added the RCA from the home theater amp. You can get another sub just for home theater like I did. Like a Hsu. Get ported so you can really shake the room if that’s your thing.
I say just get a female to female adapter and add another rca run. Placement is very important. You can extend the speakon cable since it is just a signal. Just so you understand I put one sub on each side of the left and rt speaker to add or enhance the sound of my music. I then just added the RCA from the home theater amp. You can get another sub just for home theater like I did. Like a Hsu. Get ported so you can really shake the room if that’s your thing.