Yes they are proprietary connections. one end is the color coded plug that goes into the back of the receiver, the other end is hard wired directly into the bottom of the speaker (no plug). Regular speaker wire cannot be used with out splicing. In my case, my home is pre-wired for a surround sound system and this required me to cut the included speaker wire a few inches from the speaker and splice this connection to the wires coming from my ceiling. Then I had to strip the remaining length of speaker wire (with the proprietary plug attached) and connect that to the wall plate where the speaker wires go in. Took me about 2.5 hrs do everything. Splicing requires a wire cutter/stripper and either electrical tape or heat shrink (highly recommended).

As for the length I'm not sure. To keep things as clean as possible I kept all of the cables bundled. If I had to guess there are at least 20 Feet on the rear speakers probably a little more. You may give Sony a call 1-877-865-7669.