It could be the settings in the device's "Sound > Playback" area of Windows. In the "Properties" of the output device, in the "Levels" tab there's an "Output" fader. Also in the same tab, make sure to look in "Balance" to see if there's any attenuation there. If you have an "Enhancements" tab in Properties, then I also recommend checking "Disable all sound effects".
Finally, also check the "Mixer" for the device. Left-click in system tray, click "Mixer", and if needed select the correct output device from the drop-down on the far-left fader. Make sure Breakaway is turned all the way up there.