Laptops speakers working while pluging in 2.1 speakers

[Arkadi.Kr]

Hello guys!

I`ve got laptop DELL INSPIRION, When I`m lunching mumble everything with the speakers are messing up.

I have Speakers 2.1 that I`m connecting to the laptop, and when I lunch mumble everything including PR (voice) coming from the Laptops computer and only mumbles voice is coming from the 2.1 speakers.

Everything is fine without mumble, but I can`t play PR without mumble.

How can I do that my computer will use only the 2.1 speakers.
I think, from some reason this Laptop think that he`s using 5.1 speakers.

Any help please.