https://youtu.be/XF6m7OusnwM
http://www.tomshardware.co.uk/forum/id-2754883/win dows-low-sound-volume.html

Right click the speaker icon in the Taskbar and select 'Playback Devices'. Left click the default device once to highlight it ( it's usually 'speakers & headphones' ) then click the Properties button. Click the Enhancements tab and put a tick in the box next to 'Loudness Equalization'. Click Apply to save the change and then click OK in all remaining windows and see if this has helped at all.