[eucariote]

 
As a fan of audio gear and owner of several high-end headphones, I was also selected to be one of the reviewers of the Monster Turbine Pro Copper iems.  The design goal of these headphones is high accuracy/fidelity, which might not appeal to bassheads, fans of euphonic music, etc. but it is fine with me.  In my opinion any added emphasis of some frequency range not mixed in by the audio engineer is not intended to be in the music, and so takes away from the aesthetic experience as intended by the artist and audio professionals.
 
I own several quality iems, including the original Turbines, Klipsch Custom 3 and Shure SE530 which I used as reference for evaluating the sound of the Coppers.  The Coppers have noticeably more refined bass and much greater detail than the original Turbines, which cost about half as much.  So I compared them to the Klipsch and Shure iems, two well-loved and well-reviewed iems with dual and triple armatures that cost considerably more than the Turbine Coppers.  
 
With regards to their comfort and fit, they come packaged with an impressive number of silicon eartips, silicon tips with gel and foam eartips with what appears to be a silicon center ('supertips'), which make it easy to find a matching size for your ear canal.  I normally use silicon tips because they are very easy to insert, but I found that the small foam tips could also be inserted without compressing them first, which makes them just as easy to insert as silicon tips.  These tips seem to distribute pressure over a larger area, giving them a light touch that was very comfortable.  The foam tips also block noise almost completely, which offered good isolation on a long airplane trip.  The center posts of the Turbines (original and Copper) are rather large, so they weren't quite as comfortable as my other iems.
 
To evaluate their performance, I used both an iPod (Touch 3g & Nano 1g) and a uDac dac/amp.  My full-sized headphone amplifiers have written warnings against using iems, so I used low-power sources intended for portable headphones & iems.  I used a variety of tracks that test the technical abilities of headphones and their ability to convey the pure bliss of music.  These included rock albums by Death from Above, the Yeah Yeah Yeahs, Wolfmother, Broken Social Scene, a jazz album by Dexter Gordon, classical music by Mozart, and electronic music by Goldfrapp and Boards of Canada. 
 

 
The standout feature of the Coppers is their extension both in bass and treble.  Their bass has much more presence and impact than the Custom 3 & SE530, but is also well defined and controlled.  This makes drums more noticeable in rock and electronic tracks, and while sometimes intense, they were usually better proportioned than the other iems that were slightly lacking in deep bass.  For example, in tracks by Death From Above, the double kick drum is more audible and crisp, while it sounds a little more than a low rumble with the other iems.
 
The treble is also noticeably more extended on the Coppers.  Compared to the other iems, there is considerable clarity and detail in the upper registers of music.  For example, there are drum brushes in Dexter Gordon's Ballads that I barely noiced on the SE530 that became vivid and clear on the Coppers.  However, I found that the additional treble could get a bit intense on certain tracks.  In the same track by Death From Above where the bass drum had improved, there are relentless cymbals that were at times sharp. But on balance, I felt that the treble and bass were better on the Coppers than the Custom 3 & SE530, which sounded relatively narrow and limited in their extension.
 
The extension of the Coppers gave them a more open and expansive sound, and on tracks with heavy instrumentation, individual instruments and voices could be heard more distinctly.  In an album by Broken Social Scene with over a dozen musicians, the SE530 obscured some details that I could hear clearly on the Turbines.   And far from making the Coppers sound 'clinical', these details made many songs more blissful.  For example, in Wolfmother's White Unicorn, as drums, bass, electric guitar and vocals build and layer over each other, each detail is presented with sense of clarity and crisp intensity that gave me chills on the Coppers.  In comparison, the same song sounded relatively constrained and congested on the Custom 3.
 
One area where the SE530 pulled ahead was in the presentation of middle frequencies.  In Yeah Yeah Yeah's Pin, the early guitar solo is much more forward on the Shures, and seems a bit distant and airy on the Coppers.  Here I preferred the sound of the Shures, but in other cases, the two were different but equally good.  With classical music, there is a similar trade-off, where the Coppers emphasize the sound of the symphony and the space of the concert hall in Mozart's Requiem, but the Shures seem to favor the voices in choir and strings.  In electronic music, the Turbines similarly emphasize bass, keyboards and cymbals while the Shures emphasise the voices.
 
On balance, I think the Coppers do a better job with the bass and treble, beat out the Custom 3 across the board and they are edged out by the SE530 in the mids.  After several weeks of close listening, the limitations of my beloved Shures became more obvious and I grew to appreciate the strengths of the Turbine Coppers.  While the Coppers do not beat them in every area, overall they are on par with what I consider to be one of the very best universal iems and they have very impressive sound quality for an iem that costs a little more than half the price.