For what it's worth Western Digital does extensive testing of drive performance under audio vibration, especially on mobile drives that are likely right next to a laptop speaker.
And if you check page 7 of the PDF there is a small table that indicates that this has to be at around 120dB to have an effect. I do believe that is up around the point where you risk physical pain and instant hearing loss.
Can you cite a source or provide a little more info on how you know this? I'm interested in this kind of thing. See my story above about a recent problem I had with a Toshiba drive.