Latitude 7390 -Speaker buzzing?Shaking case?

Having issues with my latitude 7390 where there is a buzzing noise that almost sounds like a spring vibrating.I notice it more watching YouTube videos with speech than I do music.It sounds more like it is coming from the case shaking than the actual speakers.

I notice it varies on what the content is,eg one youtube channel video will consistently have my speakers rattling but with a different channel it will never do it.So obviously it has something to do with how the audio is mastered in terms of frequency etc. It can get worse as the volume is higher but it can still happen at low volumes depending on the video.

I found turning up MaxxBass and turning down Details in Waves Audio has reduced the problem a small bit.Anyone got any inisight?Are the speakers not seated correctly in the case?Could changing EQ further in Waves make a difference?Just faulty speakers?