Most common subwoofer input?


I just bought a new house and I plan the build a 5.1 system in my family room. When I talk to my builder today, he suggests me to build a in-wall stereo cable for my rear speakers and subwoofer, so there will be no cable running around my family room. I know that rear speakers use normal speaker cable, however subwoofer have so many different type of input, such as: RCA, speaker wire, phono input or Neutrik Speakon. Which type of input is most common use for sub?
thx.
audiorichard
Great! thanks for answer!! I will ask builder to run 1 RCA behind the wall.
Thank you for anyone who answered my question!
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Well, you might have already run the RCA, but as a retired Electrician, I think I would have just run some PVC or flex under the floor and up the wall, to give myself options. You would have the flexibility to change your mind and/or equipment, and if you'd need to pull something else through the conduit, you could do it later.

Good luck with it and have fun.