Another thing worthy to try is to go to control panel, make sure to set the display to small icon or large icon. After that go into sound, underplayback tab choose speaker and go to its property. From there disable all the sound enhancement under the "enhancement tab". Granted, some people may not like the sound without enhancement, but it solves the volume issue.
JAWS also provides possible fix under the default configuration, when you search for sound. Just try to uncheck "Avoid speech cut off when using Bluetooth headphones or some sound cards".