I received my Senn. Momentum (larger around the ear) headphones brand new, was imporesseb by the packaging presentation (albeit excessive packing which is bad on the environment), expecting an amazing sound.
First upon trying them with the default-installed iphone (crap) compatible cable, I was utterly saddened by the faulty sound quality: virtually no treble, overpowering midrange and annoyingly exaggerated bass, narrow soundstage and subpar dynamics.
After watching a review video to find out how to swap the cable for the strditional simple cable, I noticed an amazing improvement - sharp treble, full midrange and clear bass. However don't let those words fool you: the midrange is bloated requiring a precision EQ reduction around the 1.2khz, and the bass is OUTLANDISHLY bloated. I swapped cables confirming my theory that the iPod campatible cable with its circuits and thin wiring had reduced the sonic performance of these phones). After thorough comparison between these and two other Beyerdynamic models: DT 800 32-ohm and DT 1350 on ear with tesla drivers (all done with a modi+magni amp), I realized several things: the soundstage and clarity were less than the 880s, better soundstage but less analytical than the 1350s, yet I *ALWAYS* had to do some serious EQ reduction in the mids and the bass.
After burning them in with pink noise overnight for a hopeful last ditch effort to redeem the sound quality, I plugged it into my cell phone to listen to some IDM, house &b techno. The bass was overpowering enough to make me stop in my super busy schedule and EQ it down a few notches. 5 min. later I had to stop on the street and use my only one hand avail. to further reduce the bass. FInally after my 4th time reducing the bass down to about -6db on the 60hz and about -4.5db on the 30hz frequency; also reducing both the two upper treble freq. (8 & 16khz) buy about hald the amount of the bass, it was finally "listenable"... but only for about 5 more min. until I became angry at it's V-shaped SUPER-COLORED sound signature that could not be reconed with no matter how much EQing you could throw at it. So At that point I decided to throw in my hat on the Sennheiser Momentum - opting for my Beyer 1350s (eq boost on the lows and reduction on the midrange to make it sound more realistic) and send it back for a refund until I get my next better set of portable headphones.
About the build quality I do however have mostly positive words: the quality was rugged and well built with the steal-type solid headband and the adjustable length without notches was nice, and the leather pads were comfortable. BUT in the mirror the phones looked large on my med-size head and in the 80's sunny weather walking around these easily became sweaty under my ears.
On a last note, let me tell you the bass, albeit more clear than the V-modas and the (shi**y) Beats on-ear headphones, was SO overpowering that, 13 hours after putting these headphones down I realized that my headache was a likely result of the Momentum's super exaggerated, skull thumping bass frequencies. Finally, almost 24 hours after using the Momentums I took 400mg of ibuprofin to kill my subsequent headache and the morning after happily repacked these headphones for a refund even before eating breakfast.