This was tested on a Lenovo G40, with Windows 10, version 1909. Plugging in big speakers into the audio jack produces sound, but there is no bass, the sound quality sounds like it is coming from small phone speakers.

Workaround with a Windows quirk:

• Right click on sound icon, lower right of the screen on taskbar
• Click on 'open sound settings'
• Keep this window open in the background while the video is playing
• That's it, better sound quality

If you close the sound settings window, the sound goes back to being all-treble