Frankly, I don't understand. Most sub woofers are self powered, meaning they have an internal amplifier that produces the substantial power for the sub itself. I've never heard the sub extending to power other speakers. The exception is a passive sub that is powered from the amp or receiver & it separates the bass to run through itself & the balance of the audio info is relayed to front L&Rs.
Your 7 channel Sony receiver has connectors on the back for running speaker cable to all the speakers. All from the receiver to the speakers. Not daisy chaining some speakers from one of the other speakers.
I guess I'm telling you to slack back 10 yards & punt. Well, reverting to fundamentals. Reread your Sony operators manual. Find the appropriate sketch & instructions for running those channels to the speakers via speaker wire. I spent many years just using zip cord, which is the stuff that composes extention cords. To feel better about the situation, an easy solution is to buy a roll of the reasonably priced speaker cable that Home Depot sells.
I'm not sure about the model but i know that my sub and my two front speakers are bose. Those front two are hook directly into the back of my Sony strdg720 A/V receiver (7.1 compatible but i only want 5.1). The back two speakers are not bose but they are hooked up to the sub which then is hooked up to the receiver. When i did the calibration for the speakers all of the speakers seemed to work fine. So now i hooked up my Samsung bluray player to my samsung 6series 650 52" lcd via hdmi. I have the tv hooked up to the A/V receiver via optical audio cord. When i use the blu ray players audio configuration for a speaker test all of the sound that should come from the back speakers comes out of the center one (forgot to mention that the center one isn't bose either.) In fact I'm pretty sure that i haven't heard from the back speakers since i did the speaker calibration. Is my sub (i dont hear that much bass from it at all, close to none if any) busted(therefore inhibiting sound from the back speakers)? Should i try hooking them up directly to the back of the A/V receiver?
(Tv had four hdmi inputs not sure about outputs but it does have some analog audio outs and an optical audio out: the song A/V receiver has three hdmi in and one out and two optical ins and one coaxial in and several analog audio ins: blu ray player has an hdmi out and an optical out and other plugs for 7.1 that i dont think i need.) Any ideas? if you need any other info let me know.