I picked up an Amperior last week, and after spending some time with it I can report that I am happy with the purchase. I agree with Craigster75 on most of his observations, they probably are a little over priced for what you get, the soundstage is typical of a closed supra aural can, and lack some of the detail in the upper mids/trebles compared to some other $300+ cans. That said however, for a truly portable set of headphones I think these perform remarkably well and are very detailed and "fun" sounding. For my use I wouldn't compare them to headphones like the M100s, K550s or even the D600s because i'd probably never wear any of those out of the house. I would directly compare the Amperiors to other truly portable cans like the M80, DT1350, and HD25 all of which I also own.
I hear a lot of people asking for a comparison to the HD25-iis, and whether or not they're worth the extra money. To my ears, I agree with some people here that they do sound better than the HD25s, although I would say the difference is not a big one. The best way I can describe it is that the HD-25s really do need amplification to get the most out of them, while the Amperiors do not (although they also benefit from an amp). Listening to the HD-25 directly from my Macbook Pro the mids and treble sound a little recessed and veiled to my ears, and plugging them into my NuForce Icon HDP opens it up and even makes the base a little tighter (although the base is pretty darn good on the HD25). The Amperiors are a little tighter and detailed plugged right into my iPhone or laptop, and when plugged into my NuForce it opens up even more especially with female vocals although the difference isn't as noticeable as with the HD25.
I've listened to HD-25s for many years and they have always been my "go to" portable can--until the M80 and DT1350 came out. I liked the M80 slightly better in all areas comapred to the HD25, and I think the DT1350 is pretty hard to beat (for a compact closed supra aural) for acoustic, jazz, and female vocal music, although I like them less for other genres of music (I listen to a lot of electronic, metal and rock which the M80 and Amperior excel at). The Mic is also much better on the Amperior compared to the M80. The new mic cable from V-Moda is a big improvement but still not as clear as the Amperior. I use them to take a fair number of calls on my iPhone and use Skype a fair bit and have had a number of people unanimously say that the sound quality was better with the Sennheiser mic. The Amperiors are much more comfortable than the HD-25s because of the cloth pads and less clamping force (I do not wear glasses). I would say they are about as comfortable as the M80s, perhaps slightly more so, and also easier to get a good fit with. I find I have to stretch and twist around the headband a bit to get a perfect fit on the M80, while the Amperior just seems to find the sweet spot on its own. I am able to wear both for several hours without any pain though, while I could feel the HD25s after an hour or two.
So are the Amperiors worth the extra $$$ over the HD-25s? For many, the answer is probably not, but they do sound better to my ears, especially without any kind of amplification and that is on top of aesthetics and the built-in mic which I actually do use a lot. Both are fairly detailed cans across the board for their class of can, but I feel the "veil" is a little thinner on the Amperiors. I'm definitely enjoying mine on the road (did I mention the isolation is top notch?) and when I leave the house it is really a toss up for me whether I bring the M80 or Amperior. Maybe they will be more appealing to some once you start seeing more of them on the second hand market, or once Apple loses exclusivity on their resale.
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