Quote:
Originally Posted by
ARealHero 
So I recently hooked up my ATH-M50s to my Sony STR-K502 receiver and while I can feel the headphone moving a lot when I put my hand on them, the bass doesn't rattle and punch like I'd like it too. Is it that my receiver isn't good enough? I believe I have it set at the max bass of +6dB right now.
I'm guessing it might be an impedance (Ohms) issue.
Normally (preferred) you would want the headphones to have at least 8 times (or more) the impedance of whatever headphone output your plugged into.
So the 50-Ohm ATH-M50s would sound best plugged into a headphone jack with an impedance of 6-Ohms or less, chances are the Sony's headphone jack is around 40 to 60-Ohm.
i'm guessing most receivers have a headphone jack with a high impedance
I'm guessing the ATH-M50s bass is bloated or losing detail.
Try the ATH-M50 with a quality portable audio player, usually they have a low impedance, see if the ATH-M50 sound better plugged into them.