WhatFurrer is this the type of connector you used.....
...if so, these can be somewhat difficult to find locally (was for me anyways) but here is the place I ordered mine from,
Triangle Cables. I bought a whole heap of 'em without spending too much money at all.
Whenever we built our room I bought a 1000' spool of Tributaries RG6 and used the RG6 for all of the in-wall analog cabling to the TV on 40' runs as well as the 6 in-wall subwoofer runs to the different subwoofer locations, I then had all of the wall plates terminated with F connectors and used the above F to RCA connector adapters to connect the various components to the electronics cabinet.
RG6 can be used for just about anything...
