My headphones are falling apart, so I'm looking for some new ones. And while musing around on the sennheiser site I came across http://www.sennheiser.com/sennheiser/icm_eng.nsf/root/05341. Here's the catch. It says: 'Bass reproduction below the human audibility threshold (15Hz)'. And now they've got me wondering what the point is. I mean, if they put that on an amp I would just assume that there are soundlevels that can not be heard but can be 'felt'. What's the point of having that on headphones? Does it somehow contribute to the overall sound?