Planar magnetic headphones typically have a lot of advantages when it comes to speed when compared to their dynamic driver counterparts. But when I started listening to the two headphones, I was pleasantly surprised to find that the Hi-X55 can catch up to the AEON’s speed. The Hi-X65 has almost the same sound balance as the K812, but it doesn't quite reach the same level of detail and resolution. The Hi-X55 features a proprietary 44m high excursion dynamic driver. The driver size was deliberate on their part because their experience has taught them that 44mm diameter diagrams are optimal in being able to move the largest amount of air while being resistant to ‘wobbling’. These are must have traits for a headphone made for professional use. And it does this without having the "treble murder" that certain headphones from this gang portray. The Treble of the two monitors is also tuned similarly. Both are fairly bright, with a good amount of treble extension. Cymbal hits are splashy and crisp, with an overall airiness.

If there is anything that I would improve on with the Hi-X55, is the way it presents the lower treble range. In the intro of Standing Still by Jewel, it almost sounds like it’s a real guitar in front of me. The timbre of the guitar is similar to how I hear actual guitars when I play or watch my friends play on the acoustic. Items that are likely to wear out with use, such as the earpads and headband cushion, are easily replaceable, so these headphones should provide many years’ service. The cable, too, is detachable and replaceable, though we have a minor gripe here: at 3m, the cable supplied is for all practical purposes for home listening only. According to the specs sheet, the Hi-X55 has an SPL of 118dB/mW and an average impedance of 25Ω. These specs tell me that this will be easy to drive, and that may be true. They can be driven to blaring loud levels even through my Nokia 7.2, but then my phone simply makes the Hi-X55 sound grainy and compressed.The other side of the cable has a 2.5mm bayonet system, similar to the ones found in other Austrian Audio headphones. I'm not a professional or audiophile, playing around headphones is just a hobby so assessment might not be accurate. used SoundBlasterX G6 for the source. The 1.2m length cable is comfortable to use on the go. There are no microphonics or unwanted sounds when moving with them.

It’s easy for me to find the textures of the vocals from both male and female vocalists. I just get a sense that the Hi-X55 doesn’t need to emphasize the vocal range to clearly present details. As a part of a review tour, I auditioned the Austrian Audio Hi-X55. Austrian Audio, as most will know, were a bunch of engineers that quit AKG when Harman took over the company. Since both headphones are designed for studio use, they have similar tonality. There are just 2 main differences, and it’s that the Hi-X55 has a bit more sub-bass rumble to speak of and that the Hi-X55 has a slight treble peak. Overall, the design doesn’t seem to get inspiration from AKG products of the past. Although the build is completely their own, it seems that much thought has been put into how this headphone is built.I started testing the sub-bass on the Hi-X55, and I was pleasantly surprised with its response and presence. I listened for the sub-bass rumble at the start of the song Drink Up by Train, and it was there. Although it isn’t overwhelming, it’s evident that there is a good amount of sub-bass presence. The Hi-X60 is a comfortable headphone, even for people with smaller heads like me. With the headband adjuster pushed to the minimum, I can get a secure fit. Even when using it for longer trips, it does not fall off even when I doze off. I tested for this as the ATH-m50x constantly slips out of my head, in my experience. 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... The Hi-X55 has a great amount of detail retrieval, leaving no need for actually emphasizing any frequency range. Treble

There’s a little extra bass and the handling of the mids is not entirely neutral. However, the Hi-X55 are still more accurate than plenty of sets used commonly in home studios. That precision and snap continues elsewhere in the sonic range. The treble and midrange are clean, crisp and detailed, and everything is fairly even across the spectrum. However, there is a slight tendency towards brightness in the upper midrange; this brings voices to the fore, but doesn’t detract from the rest of the piece. It does mean, though, that you should take care with any partnering electronics, and avoid equipment that errs on the brighter side of things. Austrian Audio knew what they were doing when they made this product. These are recommendable for professionals and audiophiles alike. Austrian Audio Hi-X60 Technical SpecificationsGoing up in the frequency spectrum into the mid-bass section, I find that the Hi-X55 performed really well in this portion. I like how there is a good amount of mid-bass impact, and the decay is just spot on to feel like a natural drum hit. Flower of Carnage - (Kill Bill OST) - Sounds good. Wide stage. Vocals are good, instrument detail is good. Sometimes the stage is incoherent. The left and right sides dont sound like it is playing the same song.

On the other hand, the Hi-X60 is a bit heavier and has a tighter clamp on an over-ear design. Despite greater clamp force and heavier overall, the Hi-X60 is more comfortable to use over longer periods. Performance While the two headphones are both designed for studio use, the Hi-X55 has some features that would end up making it more useful for on-the-go or even home use. It’s evident that both headphones are for studio use, but the Hi-X55 is clearly the superior technical performer of the two. Despite being designed by a relatively new company, the Hi-X55 is a very mature product that shouldn’t just be confined to the studio. Plenty of regular audiophiles will enjoy this also. Austrian Audio Hi-X55 Specifications With durability in mind, the Hi-X55 is equipped with quite a few metal parts, especially the parts that are most susceptible to wear and tear. And this includes all the hinges and the bow on the top of the headband.Moving on to a more powerful source, the Audio-GD R2R 11 supplies meaty lows on this pair. Staging and imaging are also improved compared to the Hiby R3 Pro. Sound: My first impression is that vocals on songs that I know well are unnaturally boosted. More than I’ve heard before in a headphone. Also the sound stage is noticeably narrow. More like a triangle right in front of my face rather than a full left to right stereo image. Bass runs deep and tight, but not too deep that it causes blooms to higher frequencies. The sub-bass has just the amount of rumble for the bass hits to be felt. The same goes with the sub-bass. There is bass when it is needed and ultimate silence before the beat drops. Notes are distinct and clear. Guitar strums on the Hi-X55 are also presented naturally. When I’m listening to the guitars, I can almost imagine the size of the guitar’s body and the way the guitarists are shifting their fingers through the fretboard. In general, the stage of the Hi-X65 is not as wide as that of the K812, there is also less "air" between instruments and performers.