I'm not sure what you mean when you say

"我們自己把線連到iphone上，surround sound 是work的。". You do not have a surround sound system yet. You just have a bunch of speaker wires wired in you house. You need to buy a receiver with 5.1, 5.2, 7.1, 7.2, 9.1 or 9.2 channels of surround sounds. If you want to appreciate beauty of quality sounds, you also need one or two sub-woofers. Surround sounds are recorded in your music data.

Good luck with your system!

Alex