Update: I'm not much of a believer in burn in, but I do believe giving a few hours of playback with the x55s has remarkably improved the overall sound signature. Bass seems to be a bit more lively and present in the mix. Turning on XBass on high gain even provides some of the bump I'd like to see in some of the rap mixes. Its still nothing compared to the Z7M2s, but for almost half the price, I say these do alright. Taking everything together, these are almost like a cheaper, studio version of the Z7M2s.
Just purchased the HI-X55s from Guitar Center today. They started carrying out here in the Southwest and its one of the few headphones in stock.
I asked the guy in store if I could demo them which he happily obliged. Unfortunately, the pair I demoed was defective - couldn't play anything below about 150Hz even with a 15 dBl boost out of my Walkman. Thought I'd gamble on them still, especially since I could always return if I'm truly unhappy with it. So... I've had them for about a couple hours now, been throwing all kinds of music at them, changing sources, EQing, etc. etc. - here are my first impressions...
Holy cow are these comfortable. I wear an XL ball cap and the first comment anyone makes when they try on my hats is, "Wow, you have a big head." So.... I have a big head. These fit so comfortable. However, I'm one of those weirdoes that enjoys good clamp pressure from his headphones. For instance, my HD6XXs offer a comfortable amount of clamp force for me. These don't have quite as much, but they do have more force than something like Meze 99 or MDR1AM2. I recently got the Z7M2s as well for non-critical listening and the comfort is right on par with those but with slightly more clamp force. The pads sort of just envelop your ears and its wonderful. Plus, everything is easily removable so if you need more cush, you can get more cush (though I doubt you'll need it). One person in this thread made note of the headband being plastic - it has a similar texture as plastic. I first glance I thought it was. It, however, does have a cool touch and a sturdiness to it that resembles metal. I still would refrain from forcing these to reduce clamp force. I would stick these on a yoga block instead and let that do the trick over a couple weeks.
Build quality and design are top notch. When I asked the cashier if I could demo them and he opened the box, he and I both made an audible "oh wow" at first seeing them. They're just beautiful. They're a blend of plastic and metal and they feel exceptionally durable, about as durable as my K553s. Now, with the $330-$350 price tag, I'm still going to be handling these carefully. Regardless, they have a nice premium feel to them that is reminiscent of something significantly more expensive.
Thank goodness the cable is interchangeable. The 3m cable is great if all you're doing is working in a studio, but my goodness is it pain everywhere else. Even then, I hate 3m cables because I roll my chair over them, damaging the cord. That said, the cable is decent. It has some spring and memory to it, but I suspect a little heat and straightening will fix that right up. It is a 2.5mm locking jack that goes into the headphones. I ordered two cables, both designed to fit the Audio Technica ATH series and Sennheiser HD500 series. Obviously haven't received them yet, but after carefully looking at pictures, I don't see why they wouldn't fit. It is important to note that the cable is finicky if its not fully locked in place. Initial listening made me think I had a pair of broken cans because it did not sound right, but I quickly realized I had not fully turned the cable. This is my first time with a b-lock cable so don't judge me...
Sound, sound, sound, sound.... I too, like many of you, looked at the frequency response graph and thought to myself, "holy cow, what is going on with these headphones." Yet, I still bought them because curiosity killed this cat. I appreciated Oratory's graph (
https://www.dropbox.com/s/a17yq4pkomonor0/Austrian Audio Hi-X55.pdf?dl=0). Its quite odd because you look at the graph and you think, "this is going to sound really weird", but it really doesn't... Now, let me do my absolute best to describe how these sound...
Like others have said, they are remarkably source dependent. My go-to is the Walkman ZX507 which, as most people know, does not have much power to give. Fortunately, these are easy to drive headphones so the Walkman does do it. That said, I did run these on my iFi Hip DAC with and without XBass. I also ran these on my FiiO Q3 with its very clean sound signature. What I've found is that the more power you throw at these, the better they sound. Others are right as well, pairing them with a smoother/warmer sounding DAC/amp improved overall sound signature.
Before I really dig in, I suppose I should also share my personal tastes... I listen to almost everything so my initial listening is basically just shot-gunning all of the different genres at whatever gear I'm testing. Symphony, cinematic, acoustic-based, country, rock, rap, etc. etc. The only thing I'm not really a big fan of is EDM and hard/heavy rock. I like a neutral/balanced sound signature, but I also enjoy musical/pleasure cans like the HD6XX for its warmth or Z7M2. Typically... if I can't have balanced/neutral, then I'd rather have a warmer V-shaped sound signature than something that is overly bright, OR something that is more mid-forward like the K553s.
Bass - most of your bass is going to be from about 60Hz upwards. I can slide the 31Hz slider all the way up and all the way down with no discernable difference in the mix. 62Hz does make a difference, but its more in overall warmth. There isn't really any thump to the low end. If you're looking to listen to EDM or rap or are a bass head, I would not recommend these headphones. The Z7M2s probably have the best bass (but those are about $600) because of its tight, natural and textured presentation. The bass on these isn't anything to write home about. You can hear it and its does its job. It doesn't detract from the sound, but also doesn't really add anything either. Ultimately, the bass is that of a pair of studio monitoring cans, which I believe the designers at Austrian Audio intended.
On the box, Austrian Audio claims that these can go as low as 5Hz which is super impressive. If I put the x55s on my iFi Hip DAC with XBass on, there is improved bass performance. I suspect that one could EQ or apply a bass boost and find more of the bass that he or she is looking for. I just don't have the means to do it well.
Mids - What an interesting mid range. The good news, I'm not hearing any resonance coloring the mid range which is common for closed back cans. But man, is hard to explain what I'm hearing. What I have found is that 1) its source dependent, and 2) its track dependent. These cans will reveal flaws in poorly mixed/mastered tracks. So its hard to establish a rule for these mids because it could be the headphones, it could be the music. I've listened to a couple songs with leading female vocals that make me go "yikes" because of how clinical and shouty they sound. I've listened to other tracks with the natural timbre of a vocalist is displayed beautifully. Helpful? Yeah, I don't think so. Ultimately, these headphones have a very mid forward presentation which can (
can) lend itself to clinical, bright, or shouty sounds. This isn't true for all songs, but it certainly is for several that I listened to.
It's important to note, in looking at the graph for these headphones, don't view that dip at 500Hz to 700Hz as a scoop. It really isn't. The reality is that the bottom of the dip is about where you want that frequency. Rather, you have two peaks, one at about 150Hz and another at 1000Hz. So, if you're going to EQ - you want to knock those peaks down rather than bring the dip up. If you bring the dip up, you're going to have a very rough sound signature.
Highs - I've never been great at discerning high frequencies. These headphones are bright cans. With that comes detail and airiness, etc. but it can also lend itself to sibilance. I didn't find the highs to be as sibilant as the DT770s, so I'd say that's a win in my book. I don't have much to say about the highs, but feel free to ask me questions.
Sound Stage/Imaging - Fantastic. When I demoed the broken headphones in store, I decided to take a chance because of how great the sound stage and imaging is. Is it as open as an open-back? No. But, it doesn't have the same closed, cramped, and resonant-filled sound as many other sub $350 headphones. I also find instrument separation just right. My Z7M2s have great instrument separate, almost too much - like everything is too far apart. These teeter on the line between intimate and spacious and I love it.
Final verdict... should you get these? Maybe... They're certainly worth giving a try. Like I said, I would stay clear if you're a bass head and looking for something to bring the fun out of EDM or rap. These will not satisfy. If you are super sensitive to bright sound signatures; again, I might not recommend these.
Here's my thinking, you can get something like the K371 with its Harman Curve tuning for half the price. But, you won't get the x55's spaciousness or comfort. Frequencies can be EQ'd and my goodness do these EQ well. As I was playing with the equalizer, I quickly realized that if you had EQ'd these headphones and given me them, I would not be able to tell that you EQ'd them. So, I'm not a fan of EQ'ing at all (and I probably won't these), but I think the build quality, comfort, spaciousness, etc. of the x55s picks up some of the slack that the wonky mid range gives. Keep that in mind.
Ultimately, I do believe I will be keeping these x55s. That says something because it comes from someone returns headphones/IEMs like its a game. If something doesn't impress me, back to the store it goes. Just this week, I bought the Yamaha MT7s and Shure SE225s, neither of them were that great so I returned both and got these instead. I'm going to keep these for a specific purpose - classical/cinematic music. Listening to Tchaikovsky's "Swan Lake" or Shostakovich's "Gadfly Suite" or the Game of Thrones score all sound amazing because of the slightly brighter and spacious sound signature. Most everything else is good (perhaps even great for the price tag) but I have other headphones that do it better. I can't understate how great classical/cinema score's sound though.
Sorry for the somewhat chaotic review. I'll update/make edits if my opinion changes. Feel free to shoot me any questions!