Pros: Excellent mids, comfortable, lightweight,, build quality
Cons: Bass is lacking, surprisingly hard to drive, not the best seal/ not enough clamping force
I picked up the K172's from shop.ca for around $40. I likely wouldn't have bought them for a typical price, but for the price I paid, they are 100% worth it. I will be chiming in with a week or so, maybe more, about the sound during burn in. Intially, I tried the headphones on the basic iPod. The sound was that off an AM radio and a very low volume, with just mids and highs. Simply put, the K172's need an amp, or at least a source that has better output, such as my computer. I was immediately impressed by the comfort; the headphones are extremely light, and have little clamping force, although I would prefer a bit more clamping to hold the phones on my head better, and when you press the cups to your head more, bass does get better. Everything is new though, and over time, I feel the pads will soften and compress easier despite the light clamping. Perhaps the K271's would have had a better seal, more clamping (from what I see, they are the same phones, just the 271's are circumaural, and have a few added extras.
Build quality: Coming from the only headphones I really use, the Harman/ Kardon BT's, I will base everything off of them. As for build quality, the K172's aren't what I would call worse build quality, but more for usability rather than "designer". After all, the BT's are closer to consumer headphones...but have better sound qualities an audiophile looks for compared to many consumer headphones seen in places such as the Apple store. The K172's shy away from that look, and just work, achieving a light weight and durability through a simplistic look, rather than industrious. I read that the 172's have a detachable cable, but they don't seem to unfortunately. It would also have been nice to have had magnetic or clip in ear pads, rather than ones that stretch over. Overall they look simplistic and fragile, but once you hold them you see you can tweak them every which way and they likely won't snap you.
I have use a multitude of tracks, ranging in genres, as well as in 320 mp3 to FLAC. FLAC certainly sounds better, delivering less fatigue. I used a FIIO E12 with an iPod Touch 4 for all listening.
A list of some of the songs (just looking around on the iPod and selecting what I know I really listened to with the phones) and my perception of the songs:
Inner City Blues-Marvin Gaye: Shows off the bass pop from the 172's, as well as the strong mids
Girls Got Rhythm and High Voltage- ACDC: These two songs (and most of the ACDC stuff) really need deep bass phones to hear the bass. The BT's show it off well in bass boost, the 172's not so much, although the bass still has a presence.
Allegro Ma Non Troppo- Beethoven: Really shows off the mids of the 172's, but misses some of the power of the low strings that the BT's show in the song at times.
Come Alive, Over Your Shoulder, Lost on the Way Home- Chromeo: Lost on the Way Home showed distortion in the low bass on the 172's when bass boost was used, as did Come Alive. I am hoping bass will come forward more in burn in, as bass with bass boost is actually too much much anyway...yet not enough without it. The BT's had perfect bass without boost, and incredible bass with it.
Get Lucky and Doin' It Right- Daft Punk: Bass came out nice without boost on the 172's, but not a rumble. Now Doin' It Right, on the BT's, they handle huge bass rumbles in bass boost. They do rattle on the left driver because of them being dropped. The 172's... forget it, they make no bass at the frequencies of the sound, and with boost, you can heard the drivers distorting...not just a distortion, but the exactly what is happening with the distortion. Perhaps burn in will help.
Money For Nothing and Industrial Disease- Dire Straits: Despite the hard hits, there is no distortion of the 172's at any point. There is great punch, and nice clarity and brightness
Fleetwood Mac-Greatest Hits: Whole album pretty much. Sounds clear, punchy, yet crisp on the 172's. Bass isn't as strong compared to the BT's of course, but the BT's miss the mids and highs that the 172's bring forward in this album.
Touch of Grey and The Music Never Stopped- Grateful Dead: Both sounded great, although I like a tad more punch that the BT's can deliver.
Multiple songs of the Commodores: The 172's shows off the vocals very nice, delivering a good sparkle. There is punch to the bass when needed. Overall, the Commodores sound better on the 172's than the BT's.
Mickey Hart Band- Mysterium Tremendum and Superorganism: Mickey Hart produces some neat stuff, songs of which have great vocals, odd little noises that need good headphones to hear, and good bass. The 172's show off clarity in the mids better than the BT's and a little more clarity, but are missing some nice bass. I guess both phones are equally good with Mickey Hart, just in different areas.
Pink Floyd- Endless River: A very instrumental, mid and treble oriented album. The 172's give a good sparkle and soundstage.
Steely Dan- Greatest Hits: I can't stay Steely Dan is a group with big bass, so the 172's accurately represent the songs, giving good clarity to the mids.
Many more songs, although I found myself picking natural bass songs, rather than stuff like rap, or current music. The 172's show off the pop of the drum kick, or a shake in upper bass, but when you get to a song where there is an electronic 10hz note coming through to rumble the ground, the 172's can't take it. The BT's, on the other had, have little issue with any range of bass, and can really make your head rumble...but not a muffled one like something like Beats produce
Treble: Coming from the H/K BT's, treble is slightly brighter in thr K172's, bringing out some vocals more in lower treble, but really more noticeable in the sparkle in upper treble, where high notes that are often simply just heard have a decent ring to them. On mp3 songs, this can lead to sibilance, but on flac albums or songs, I can feel the note without feeling pierced by it. The treble isn't that forward though, and I am sure there are a number of headphones out there with a lot more treble.
Mids: The focus of the 172's. They are very forward, very lively and very crisp. In some cases, it can be too much mids, but overall, the phones just bring out the main parts of the songs very well, and you can hear all the is happening. Nothing drowns out the mids in these phones.
Bass: This is the failing point of the 172's. The are extremely light on bass. I feel that they have been improving since I first listened, but I hope the bass will deepen a bit more. The 172's have little issue with drum kicks, and bass instruments can rumble, but the bass does not extend low enough, and when it does, it can distort. Electronic forms of bass are terrible, such as Daft Punk or forms of rap. The 172's are a phone that likes classical, classic rock, earlier electronic music like Moby and Thomas Dolby, or music where the bass wasn't simply meant to be the whole song, but merely add to a song.
Soundstage: Soundstage is actually quite nice with the 172's, a bit better than the BT's but this could largely be due to the mids being more prominent. Clearly, open headphones would scoff at the soundstage of the 172's or the BT's.
Overall: The 172's are a nice headphone, especially with the cheap price I paid for them. If they were over $100, I would look elsewhere. While they present clarity and the mids and highs better than my Harman/Kardon's BT's, they have less bass, and distort very easily in the deep bass. I still like them, but not near as much as the BT's; I can survive with a phone that is a little too warm, but I feel that AKG should not have a phone that distorts on any form of music. Less bass, fine, but having distortion on a lesser degree of bass than the BT's (even when the BT's are not use the bass boost of the E12), not really acceptable when you get into any range like AKG. The 172's leave a listener to pick what music will actually work. Any headphone has a genre that is best, but every headphone should not have trouble producing sound
I will continue to burn in and see what happens. The headphones have already improved from when I first received them, so hopefully they will improve a bit more.