How to wire center/sub speaker cables to a TRS plug?

[Fire-Flare]

I've decided to replace my aging surround sound system by connecting the speakers directly to my sound card, but I don't know how to wire those two.

Logic tells me that the center channel would be the tip because mono defaults to left. But I don't want to solder twice.

Please advise.

[danimal]

sound cards don't put out nearly enough power to drive speakers, you need an amplifier between the speakers and the sound card.