Just a thought... Please could you try switching the audio settings to stero instead of surround, and see if that fixes it?
I've looked for such options in the Pulse Audio volume controls but I haven't found it. I can only select there HDMI-Devices and the internal speakers of my notebook (Dell Alienware) but as I don't habe any HDMI device connected I use the settings for the internal speakers. But I will see if I can find something later. :)
But I found something else interesting. I have connected my Fiio Q1 Mark II (FQ1222) DAC via USB to my Notebook and used this as the sound card. Now the sound is perfect! This would be a good solution for me but I think it would be interesting for the developers what's causing this problem. If I can do anything to help you, please let me know.