I purchased these to serve as a dual-purpose music listening and audio production headphone. I am driving them out of my Little Dot MKII and Beresford TC-7510. They've also been recabled by Fitz with his black clover cable.
 
Highs: The highs are my least favorite thing. They don't extend that far and lack presence, although they are by no means bad. They're reasonable detailed.
 
Mids: Beauitiful! They're beautiful and rich and luscious. Female vocals especially sound good. They also seem to exist in their own space, seperated from the rest of the music. It's lovely.
 
Lows: I have the bass heavy LP version and the lows are kinda average. The extension is alright but they're a bit loose. They don't have much punch or tightness.
 
Soundstage: The soundstage itself is pretty small but the placement and seperation makes up for it. Every instrument exists within it's own space and as a result they feel airy and spacious, despite the small soundstage. I can pinpoint each instrument in the mix. When something comes in it seems to be exactly where it should be. This is one of the main strengths of the Sextett.
 
Detail: The detail is also fantastic. It's almost Ety like. I'm picking up things I've never heard before, like the final decay of the reverb on a snare, or an intake of breath. This makes them pretty damn good for audio production.
 
Compared to my HF2 they're a few seats back and don't have that same crunchy Grado involving energy, but nothing does. What they do have is a very good sense of musicality. They're involving. If I want to I can go delving into the music, focusing on one individual instrument, but I can also sit back and let it present itself around me. Despite their technical faults (lack of treble and bass extension, small soundstage) they do enough things RIGHT to be very enjoyable.

 
People don't usually review headphones three years after purchasing them but I feel obliged to review the cans which effectively ended my head-fi journey. This won't be incredibly lengthy (he says before accidentally writing something incredibly lengthy.) I will be selling them for reasons which I will delve into later, and I want to get my impressions down before they go.
 
But first, some background. Of course you can skip it if you want.
 
The Alessandro MS1's were my first audiophile headphones and I absolutely loved them. They were so intense and crunchy. I loved the way they made me feel the energy of the music. Despite this I couldn't just stop there (this is head-fi after all) so I picked up some Sennheiser HD580's. I liked them for music which suited the extra space like Jazz and Folk but found them too dark and didn’t listen to enough of the genres I enjoyed them with. Eventually, and unexpectedly, the Audio Technica AD700's drove me to sell the MS1's since for me they struck the perfect balance between space and energy. They've stuck with me to this day because of their versatility, huge soundstage, and sweet tonality. My discovery of Etymotics, however, lead to a quest for detail and after trying the AKG K701, '03 Beyerdynamic DT880 and Stax Lambda Pro I eventually realized nothing full sized really sounded like Ety's and returned to the AD700.
 
Although I still very much enjoyed the AD700's sound signature, my foray into higher end headphones had left me unsatisfied with them. The DT880's in particular impressed me greatly with their detail and more neutral presentation, and I would have kept them if it weren't for the awfully recessed mids. I wanted more, and when the HF2's were announced I impulsively jumped on them for a number of reasons. I wanted to know what a higher end Grado sounded like, if they fixed the issues I had with the MS1's. I also liked that Grado took the time to create something special for the Head-Fi community. As it would happen, the HF2's DID fix the issues I had with the MS1's and aside from a brief experiment with the Grado SR225 they have been my primary music headphone for multiple years. I had no reason to return to Head-Fi because of them. I was done.
So I guess I'll begin my sound impressions. These are all with the stock bowls through my Little Dot MKII and Beresford TC-7510.
 
 

 
 
First the highs. The highs are what set these apart from other headphones I've heard. They seem to manage to be very present and sparkly without being overpowering or fatiguing. They're just SO clear and detailed, yet are still balanced. The highs on the MS1i in comparison sound grainy and smushy (please forgive my non-standard audiophile terminology, I've been out of the game for a while) and tend to make things sound overly bright and sibilant. The overall tone on the HF2 doesn't even sound particularly bright to me.
 
Now for the mids. The mids are more bright than they are warm, however they’re not as bright as the MS1’s or even the AD700. The HF2 mids are just a tad more neutral and sound less “nasal” than the MS1i. This is another thing which attracts me to the HF2s. They’re most definitely Grado but they’re a slightly more neutral and “realistic” Grado, whilst still retaining most of the Grado magic. They still have the energy.
 
And the lows… The bass greatly contributes to the overall darkish tone. Compared to the MS1i’s it’s definitely more prominent. If I had one criticism it would be that the bass is slightly looser than I like it to be, but this probably isn’t helped by the tube amp. I mean it definitely isn’t boomy but there’s definitely a mid-bass hump going on. I’m not really a fan of bass in headphones. I was perfectly happy with the bass-recessed AD700’s. But I don’t really mind having a little more bass, and I think it actually adds to the energy. It gives electric guitars a little boost in the low end which makes them punch harder. It makes everything sound thicker and fuller. It also extends fairly deeply, but the mid bass hump can cause the deep bass to get overwhelmed by the mid bass. I much prefer the bass on the DT880’s if we’re comparing individual sound characteristics, but I think the HF2’s bass works well in the context of the HF2’s.
 
What apout soundstage? These are Grado’s so soundstage width and depth isn’t really what they’re about. Placement is excellent, and they have enough width to create a good sense of space. They don’t sound closed and boxed in like I remember my MS1’s sounding, or like the MS1i’s sound today. There’s space and “air” between instruments which isn’t there on the MS1i. Things sound less congested in more complex passages. It’s good.
When you've been enjoying a single pair of headphones for so long it's difficult to objectively explain why you like them. They just sound so right. Returning to them after listening to the AD700's for a while, or even some borrowed MS1i's, is like coming home. Every aspect of the sound comes together perfectly.
 
So why am I selling them? Basically as a starving student I can no longer justify having $400 headphones. Sure I love them, but I also love my AD700’s. I definitely don’t enjoy them four times as much as the AD700’s, despite paying four times as much for them. I’m also hoping to get into some home recording would benefit from something more neutral and revealing. I have a pair of K240 Sextetts on the way and they should satisfy me sufficiently. If not I’ll keep looking until I find something which at least partially fills the HF2 shaped hole in my heart.