Double line out usage

Hi,

I’m trying to get my sound to play from 2 stereo devices, but they both use a separate line out from my computer. There are 2 of them on my box, 1 in the back and 1 in the front, but if I connect both of them to a separate device, I can only hear sound from the 1 that is connected to the line out in the front.

Is there a way to have them both work simultaneously and how can I do it if so?

If you want the same program on both why not just get a hardware line splitter? It’s a Y plug with one jack and two sockets.