They do not have exaggerated bass. You don't need too much bass whilst listening to a country song, for instance, and Momentum don't have too much bass in that kind of songs. But if it's a bass heavy genre such as drum'n bass or hiphop, then Momentums can certainly deliver the bass. It's not an unrealistic, disturbing bass like Beats or similar garbage. K550 have a wide soundstage but certainly falls behind Momentums in the bass department. It all comes down to preference in the end. A basshead would most likely prefer Amperior instead of K550 or Momentum.
I have never tried the Amperior, but I have heard some people say that the Amperior is more neutral than the Momentums.
Quote from user KG Jag: "No the Amperior has a neutral sound signature. It's the Momentum that is a semi-lifestyle can with more bass; but it's not enough more to make it a bassshead can."
I don't think any of those three headphones are bassy enough for any basshead to enjoy. I also wouldn't categorize either the K550 or Momentum as having exaggerated bass especially when compared to other headphones in this category such as the Sony MDR-1R, UE6000, Ultrasone Pro 900, or V-Moda M100 (those headphones definitely have more bass-emphasis than the AKG K550 and Momentum from my comparisons).
However, I thought there were slight differences in the bass between the K550 & Momentum when I tried them, so I can see that someone may prefer one over the other.
From my personal experience, I thought that the K550 bass extended deeper down to lower frequencies while the Momentums may have a slight bass quantity boost over the K550. I personally found the bass of the K550 to be nicer, more detailed, and textured compared to the Momentums, while the Momentums had slightly more bass quantity. However, they both sounded nice and also I feel like their sound is very dependent on their fit, so if the headphones don't fit well for you, you may not enjoy the sound as much.
Edited by money4me247 - 4/2/13 at 10:48am