I'm interested in playing around with my HD238s. I've been able to pick up a lot of ideas for these phones specifically by looking at threads here and information around the internet (see here for foil/felt mods and here for a vent hole blocking mod) as well as a wide variety of information about other phones (like the HD555/595 conversion and a set of Grado mod options.)
While I have a good idea of what kind of mods people perform, I have only a shaky idea of how and why these mods work.
Can anyone please point me at any sort of guide, book, etc. that would help me gain a better understanding of how this stuff works? I'm planning to experiment this weekend and see what works for my ears, but I want to develop a better idea of just what it is I'm messing around with, and why different ideas may or may not work. So far I can't seem to find much in the way of detailed or consolidated information, and I'm only picking up bits and pieces from explanations of some of the mods and how they affect one specific design.