you've got to have the speakers set up right to get a good mix.
If you've got the speakers facing directly at you are just doing mono
From yamaha's site.
For both stereo and surround mixing your position in relation to the main front speakers – the "sweet spot" as it's often called – should be one apex of an equilateral triangle. In other words your distance from either speaker should be the same as the distance between the two speakers. The speakers should also be "toed in" to the corresponding 60° angle so that the drivers are aimed directly at the listening position. The height of the speakers should be such that the tweeters are roughly aligned with your ears (this is because high frequencies are the most directional).


Also to get a good stereo image the speakers need to be far apart depending on what they are.
Studio monitors that are nearfield monitors need to be 3 to 6 foot apart, depending on how they are made.
Regular stereo speakers are designed to be listened to at least 10-12 feet apart, the farther the better, 8 feet is a minimum