I want to understand more about how certain mods achieve sound changes. I'd like to have a better understanding of how these things work so I can tinker a bit with headphones that are not commonly modded, as well as understand how common mods work better. Firstly, the application of damping material in the HD650 mods... my understanding is that is adding weight to the driver, preventing unwanted vibrations. Is that correct? If that is correct, what then does less unwanted vibration do? Does it just allow the driver to reproduce more accurately? Next, what exactly does non-slip matting over the driver do? Is it absorbing reflections? If so, what does absorbing reflections do exactly? Lastly, when I was trying to get more bass in my Koss A250s, I was recommended to add some venting holes in the fabric covers of the back driver vents. How exactly does that increase bass?