Try disabling surround sound/audio enhancements on your current output device. To do this, right click on the speaker icon in your windows task bar and select "Playback devices", then right click on your output device and select "Properties", finally select the "Enhancements" tab and check the "Disable all enhancements" box. Make sure you apply these changes.
If you have a soundcard configuration program, or a specific driver program for your output device, you may also need to disable surround sound there.
If this doesn't work, please try using a different output device. That means a different pair of headphones or speakers.