I am looking for some info and a picture of these K4's by AKG. From what I know they are supposed to be 2way headphones, yet I know nothing more. Does anyone know anything about these? Spec's? How they sound? Are they worth anything?
What does the weight have to do with efficiency? Unless you mean there is no way in hell there is a transformer in there because it can barely fit the dynamic driver. And the electret must be quite tiny, if it's housed in the metal rings. In which case that makes sense.