Youtube review: http://youtu.be/g8oNtPYZ5NA Photos: http://dalethorn.com/Photos/Leica_Dlux6/Headphone_Nuforce_Hp800_01.jpg http://dalethorn.com/Photos/Audioforge/Nuforce_Hp800.jpg Sources: iPhone5 with Portaphile Micro/PA2V2/Decware Zen Head amps using the LOD, various computers using Microstreamer/Beyer A200p/v-moda Verza DAC/amps. Review notes: My first impressions of the sound of the HP800 headphone are based on direct comparisons to other headphones - the v-moda M100 and XS, the FAD Pandora VI and IV, the Beyerdynamic T1 and T90, the AKG K812 and K712, and notes that I've accumulated from many prior reviews. I describe how I relate to the HP800 (i.e. my personal tastes and how I use the headphone) only after covering all of the objective issues. Summary of sound: I find the HP800 sound very upper-bass emphasized, with a fair amount of boom that varies according to the particular track it's playing. My closest compare headphone is the Soundmagic HP150, whose MSRP is a little higher than the HP800, however the HP800's street price has fallen to less than $80 USD of late, which correlates better with its sound quality relative to the HP150 and other similar closed-back headphones. I equalize my test headphones, partly to get the best possible sound out of them, but an equally important reason is to show graphically what they sound like in actual comparisons to other well-known headphones. In the case of the HP800, the lower treble has a +/- variation of 4.5 db which is quite good, but the upper bass emphasis intrudes on the midrange quite a bit, masking a lot of sonic detail. If a user can correct that bass emphasis to some degree, they may find the HP800 to be a very good performer. Soundstage gets a lot of mention in headphone reviews, but rarely does anyone comment on how much frequency response affects soundstage. In the case of the HP800 quite a lot, but with the corrections I've done (see the above chart or the one on my dalethorn site under Photos and Audioforge) the soundstage is excellent, especially for a closed headphone. Isolation is average or better, and the leakage is very low, such that you may be able to play the HP800 in a very quiet office or public library at near-audiophile volume levels without disturbing people nearby. The HP800's build quality is spartan but very good, with aluminum earcups and a fabric-covered detachable cable that looks rugged. The earpads are soft and squishy and comfortable, but some users may have a problem with the partially around-ear design, where the round earpad openings are only 45 mm in diameter. My ears nearly fit into the openings, and yet I find it comfortable by making a few adjustments after putting the headphone on for listening. The HP800's sensitivity is OK for use with iPhones and similar music players, but several of my lower-volume tracks require the volume to be at maximum. Like most decent headphones, the HP800 will sound much better with a good headphone amp, although the overall response or signature won't change to a significant degree just by adding amplification. While the overall sound quality does improve with a decent amp, the biggest gain will be with low-volume tracks, since playing those tracks at maximum volume on a phone will likely produce greater distortion and clipping than playing medium-volume tracks with the volume control backed off of maximum. The comments in the music tracks listed below can be compared to other headphone reviews I've done, to get an idea of how the HP800 plays the different music tracks listed here compared to other headphones. My suggestion is instead of reading each comment below as an absolute unto itself, you could compare these notes to other reviews as they get posted, and see how the HP800 compares with each individual track.