Pros: Clarity and full spectrum balanced sound with no obvious flaws.
Cons: mediocre volume without an amp.
My previous benchmark was the Audio-Technica M50, but WOW, edging them out is these beauties, the Shure SRH-550DJ; i heard a report in the local newspaper that the Shure SRH-550DJ got jailed for taking a baseball bat and giving a beating to the competition.
I have to say that this review is with the Shure 750 earpads replacing the standard ones. With the standard included earpads the sound has a lot of room for improvement.
But i have noticed that the removable ear-pad does actually contribute to the reasonable quality sound of these, because when i take off the ear-pads and leave the driver exposed, well hey, the raw sound just collapses into a heap of rubbish, the sound ends-up like a $2 Chinese IEM, so it does perplex me how on earth the ear-pad is the main factor in deciding the sound out-put from these 550's, but oh well, no probs, that it just the way it is; so then i decided to put the Shure SHR-750DJ ear-pads on these, and WOW, NOW WE'RE TALKING! That's better. The standard ear-pad that comes with these does not allow them to perform at there best even though it does still sound reasonable (with amping); it has more than adequate high-quality sound no doubt, but then using the Shure SRH750DJ ear-pads make them shine like a pro, don't ask me why, but it is true. So just remember, if you want the best out of these you might want to buy some replacement ear-pads from the Shure SRH-750DJ model. I use the FiiO E12 heahphone amp with these and the sound is damn good, can't get much better than this i reckon; save yourself the heartache of wasting $1000 on some esoteric over-hyped piece of crap.
Overall, with the SRH--750DJ earpads, the bass is just right with good weight and not over-emphasized. The entire mid-range is full of clear natural detail, and the treble audio spectrum sounds open, clean and natural, plus the whole audio spectrum sounds clear and balanced... what more can i say, oh, and the stereo imaging is very good. Overall these Shure SRH-550's are hard to beat when using them with the Shure SRH-750DJ ear-pads.
I have used many headphones but these should definitely be on your short-list to audition, as long as you replace the standard ear-pads. With the standard ear-pads they sound a bit muffled and quirky in the midrange, lack bass punch, and the treble sounds a bit quirky although clear enough in general when using a headphone amp.