ms1i & hd555

..... from my point of view, they will have just following things in common - both are dynamic, open with imp.32 ohms.

Sound (depending on many threads here and at other hifi/audio forums, too) will be diff. like, night and day.

But, wait for a while: I am pretty sure that more than one of head-fier´s have them both, and they´ll give you straight answer.

So, guys?

The Grado's are treble oriented and can be piercing or strident sounding. Their mids are also colored in a certain way that make guitars scream. Bass is tight and impactful. Very little soundstage is to be had out of these.

The HD555 has a wide soundstage. Their treble is smooth but still extended. The mids are far more neutral sounding than Grado's and were better suited to a wider range of music. Their bass is good, but has less impact.

That's my impressions. I would only buy a Grado if you listen to metal or rock.

^ That's the general consensus: Grado's are great with Rock/Metal, etc. genres of music. It seems like they would go good with hip hop as well (certain types) but I haven't read anything about that. 

The canard that Grados are not good for classical music quite frankly is generally spread by people who simply are not knowledgeable about classical music; it's nonsense. (As a dogmatic blanket statement, that is; of course as with any can there are some as likes 'em and some as don't.) The claim that they're freakishly bright might come from people who don't know how to wear Grado bowl pads properly (they're supposed to be on the ear not around it- and I also suspect that incorrect placement on the dummy head is what's gone wrong with the response curves on Headroom, which show a substantially bigger upper-midrange rise than what I hear from my SR80s.) I now have Ety MC5s- designed, as with all Ety's, to be very neutral- and my SR80s are only a hair brighter, and overall very similar in timbre, much more similar than either is to several other cans I've heard/owned. I take that as independent confirmation that Grados actually are more accurate than they're given credit for around here (as opposed to, by lots of audio reviewers over the years. Recent example.)

The HD555 is more laid-back, but as supersleuth said, placing of the headphones on the ear plays a BIG role.

Originally Posted by supersleuth 

 The claim that they're freakishly bright might come from people who don't know how to wear Grado bowl pads properly (they're supposed to be on the ear not around it- and I also suspect that incorrect placement on the dummy head is what's gone wrong with the response curves on Headroom, which show a substantially bigger upper-midrange rise than what I hear from my SR80s.) I now have Ety MC5s- designed, as with all Ety's, to be very neutral- and my SR80s are only a hair brighter, and overall very similar in timbre, much more similar than either is to several other cans I've heard/owned. I take that as independent confirmation that Grados actually are more accurate than they're given credit for around here (as opposed to, by lots of audio reviewers over the years. Recent example.)

Amen.  :-)  I just got a pair of K601's and I was really surprised by how similar they sounded to Grado SR80i's.