[asilker]

I just got a worn pair of AKG K77's for pretty cheap. I read the thread discussing the addition of cork and sticky tack into the enclosure and now I'm interested in other potential modifications. I know that there's probably a limited range of things you can do in such a limited space, but go ahead and help me brainstorm. I'm down to clown with these bad boys. Would something like drilling back holes change the sound drastically?

 

[GREQ]

First I would exhaust all possibilities of non-destructive/reversible mods before even thinking about drilling holes etc.
 
Especially since they're 'semi-open' already, drilling would probably make little to no audible difference to the overall sound.
 
If you have some, try rolling different earpads of different materials. 
 
With dynamic drivers, I like to remove the rear-vent damping and replace it with other damping schemes until I find something I like.
But often this type of mod is destructive since the thin damping material is so fragile, and many dynamic drivers don't respond well or at all to this kind of modification. So again, exhaust all other mods before considering modifying the actual driver itself.