Really wierd speaker issue

[Falcoor]

I have a pair of Bose Music Monitor speakers and im having the wierdest issue with them, when testing in windows i only get noise out of the speakers when it tests the right one however i get sound out of both speakers then in mono. Obviously ive set them up as stereo and tried with a pair of headphones which tested fine. Ive also tried a USB sound card and im having the same issue with the speakers. If the left speaker simply didnt work obviously it would be at fault but how the hell can I get mono out of both speakers ??