ATH M50 Bass lack?

I guess you are an accute basshead is that the right word 'accute'.. m50 has good bass in quality, punchy and pretty fast, but if you want impact and slamming bass, then m50 is too neutral for that. you should get the ATH Pro700mkII which is a bassheavy headphone...

cheers,

Maybe you simply do not have a good seal. Does the bass change if you push the earcups towards your ears ? If yes, try to adjust the headphone to make it fit better. But if you are used to speakers, the bass may seem to be lacking because it can only be heard with headphones, while with speakers you can both hear and (at high volume) feel the bass as well, which increases the perceived impact.

Which audio source are you using?

Maybe you're not getting a very good seal around your ears.  This can make the bass seem to disappear.

Serious question, were you expecting something like this :

or is the bass just not as there at all?  There's a difference between wanting more bass and having no bass.

Source is everything. My crappy $500 HP gives no bass (and no highs, either, really), but hooked up with my Fiio E10, the bass feels plentiful. If you want more, I've read that the M50s are nicely responsive to EQ. 

What's your source (ie computer soundcard) and what songs in particular are you listening to?

Also, good bass just isn't bass you can feel.  If you were expecting the type of visceral bass from a full-size speaker array, then you'll never get it from headphones.  Headphones will never produce the same type of natural visceral bass without enhancements, as their drivers are only 40-50mm large-- they don't push a lot of air.  With headphones you're usually pushing the bass to completely unnatural levels to get any sort of impact.  When people mention impact on the forums, they're grossly over exaggerating for the sake of comparison.

M50 doesn't need an amp and i m really surprised that you didn't hear bass.

I hope that is a genuine product not a fake M50 like some.