Is there any way to downmix audio to stereo on more speaker channels?

[schray]

So, I have an Asus H87Pro with a Realtek 5.1 audio device with windows10.
I have two 2.0 device, an amplifier and a hi-fi(aux). I want to use both, I do not want sorround sound, just the same stereo on both. I connected one to the main channel, and the other one to the side speakers channel. I only seem to able to use them with 4.0 sound, so only 2 funktions, or I got sorrund sound in games, or something bad during movies.

Is there any way to resolve this via software, or I need an a jack splitter?

 

[basroil]

Just get a passive splitter, you might lose a bit but it'll work just fine. If your drivers support independent headphone outputs, you might be able to set back and front to the same