Bullshit, I'l listen to my music however I want thanks.
And headphones affect this far too much for there to be a strict 'limit.' If you buy a bog standard set of £10 headphones chances are you will listen to your music at a far higher volume than if you had a good £50 set of headphones - obviously because the clarity and bass is far better on the better headphones so you dont need to turn the music up as loud to hear the details.







