Sound:
Audeze describes the LCD-X as the most neutral model in the product range, which is true. However, realistically, its sound signature differs a little from that of completely neutral sound, as do most other headphones in the upper price range (the HD 800 is even more sounded in some areas), the typical American listener would probably call the LCD-X "neutral-ish". I'll go into this in more detail in the following:
Tonality in a Nutshell:
Roughly speaking, the sound of the handcrafted American headphone can be described as a balanced to bass-oriented, with a tendentiously warm and dark sound and a slightly set-back treble.
The bass range is evenly linearly raised, in the very deepest bass there is a level drop, which is due to the Fazor technology, which all LCD-Xs have (the same behavior can be seen in the LCD-2F compared to the frequency response graph of an LCD-2-non-F). In practice, however, in my experience, this drop is irrelevant and frequencies below 30 Hz are rather a minority in music anyway (and the Audeze extends way, way more linearly than what most dynamic driver headphones are capable of).
The mids are a little too present to pass as neutral and the fundamental, which is evenly accentuated along with the bass, bleeds somewhat into the lower mids, giving voices a slightly warmth touch.
The lower treble is recessed, reinforcing the impression of the slightly warm mids and giving the LCD-X the typical "Audeze house sound".
Subsequently, the level rises again in the middle highs and super-high frequencies, but is still a little underrepresented compared to the rest, so that the highs never seem unpleasant or intrusive and recordings with too much high frequencies, as can be found in many new music productions with accentuated bass and high frequencies, are not annoying.
Super treble extension is flawless and apart from the peak at 5 kHz (that still remains below 0) I don't hear any peaks or sudden dips worth mentioning when sweeping.
The bass range can build up a nice bit of pressure and power and has a nice body, but it's not quite as fast as the one of the HD 800, yet it's more tactile and visceral with the LCD-X (the bass grumbling on some electronic music pieces with several parallel bass lines is quite appealing and also noticeable), although it doesn't have the same level of precision as the HD 800, where the bass decays faster and is tighter, more precise. However, the LCD-X bass is also miles away from slow and still tight, although not to the same degree.
Resolution:
The detail resolution of the LCD-X is high, but this doesn't necessarily become apparent on first hearing.
Although the LCD-X does not uncover bad recordings mercilessly, which is due to the lowered lower treble, it manages to display details finely, which it achieves not by emphasizing the upper frequencies, but by true resolution. At first, the Sennheiser HD 800, for example, seems to resolve better than the Audeze, but that's not the case: the HD 800 appears to have a higher resolution, especially in the high frequencies, which is due to the fact that it is somewhat accentuated here.
When switching back and forth and making longer comparisons, it is actually the LCD-X that reveals more micro details in the highs, but presents them more subtly due to the slightly restrained level in the middle and upper highs.
The qualitative difference to the HD 800 is really only minimal though and the LCD-X is only a razor blade's thickness ahead of the the Sennheiser.
What I find remarkable about the LCD-X is that, to put it mildly, it still makes bad recordings very audible and doesn't want to be an acoustic magnifying glass, which is due to its clever tuning to a high degree.
Old Led Zeppelin recordings, for example, are barely audible to me with my HD 800 since it just uncovers everything relentlessly, while the Audeze presents them wonderfully, without me having any problems listening to an album until the end, without feeling the urge to take the headphones off or get the CD out of the player first. This is certainly mainly due to the different sounding, because in terms of resolution I see the LCD-X, as I said, a tad above the HD 800, at least when it comes to the highs.
Spatial Presentation:
The stage of the LCD-X is rather small, but I still think it is well done, because it offers a good and authentic three-dimensionality with a lot of depth and a nice arrangement of the individual depth layers, and for me it is also more coherent than that of the HD 800, which I find somewhat strange in the representation of spatial depth, because it offers depth, but for me it is not really authentic and appears a little unnaturally layered and not deep enough in relation to the width, which doesn't stand out negatively in classical and electronic music and is even pleasant but might sound out of place/unnatural with jazz, pop or rock music.
What the LCD-X doesn't master so well is to convey acoustic emptiness between instruments. If, for example, there is empty space/large distance between instruments, you can hardly hear it on the Audeze, unlike on the Sennheiser, which presents it almost frighteningly precise and vacant, as well as a few of my higher-priced and custom-made in-ears.
Conclusion:
The LCD-X is a great headphone with a moderately bassy-dark sound and very high detail resolution, which you don't necessarily notice on first listening.
Although the headphones have a very high resolution, they are a musical palliator in the positive sense of the word and make even average recordings still sound good without masking details. You won't find a sonic scalpel that uncovers bad recordings mercilessly - the Audeze doesn't even want to be that - instead you get a musically yet balanced tuned headphone for the price with a nice bass body and good sweetness in the midrange, as well as an authentic sound that, in my opinion, can still deliver its best performance with rock music.
If, on the other hand, you're looking for a wide sonic stage, the Audeze LCD-X, which is rather intimate but deep and precisely layered, might not be the right choice for you. Of course you also have to consider the high weight of the headphones, which causes many people problems - previous testing is obligatory here.
Apart from that, I see the sound of the LCD-X on a par with that of the Sennheiser HD 800, with the latter playing more precisely and tighter in the bass range (albeit with a less linear extension towards the real sub-bass), which the Audeze, however, makes up for with the more perceptible bass body.
Both are good headphones, but their sound signatures also differ quite a bit (the HD 800, for example, has a slight v-shape tuning with a small hump that extends from midbass to the fundamentals and also has an emphasis in the upper and middle treble, whereas the LCD-X has a uniformly raised bass and fundamental range, as well as slightly reduced trebles).
Audeze describes the LCD-X as the most neutral model in the product range, which is true. However, realistically, its sound signature differs a little from that of completely neutral sound, as do most other headphones in the upper price range (the HD 800 is even more sounded in some areas), the typical American listener would probably call the LCD-X "neutral-ish". I'll go into this in more detail in the following:
Tonality in a Nutshell:
Roughly speaking, the sound of the handcrafted American headphone can be described as a balanced to bass-oriented, with a tendentiously warm and dark sound and a slightly set-back treble.
The bass range is evenly linearly raised, in the very deepest bass there is a level drop, which is due to the Fazor technology, which all LCD-Xs have (the same behavior can be seen in the LCD-2F compared to the frequency response graph of an LCD-2-non-F). In practice, however, in my experience, this drop is irrelevant and frequencies below 30 Hz are rather a minority in music anyway (and the Audeze extends way, way more linearly than what most dynamic driver headphones are capable of).
The mids are a little too present to pass as neutral and the fundamental, which is evenly accentuated along with the bass, bleeds somewhat into the lower mids, giving voices a slightly warmth touch.
The lower treble is recessed, reinforcing the impression of the slightly warm mids and giving the LCD-X the typical "Audeze house sound".
Subsequently, the level rises again in the middle highs and super-high frequencies, but is still a little underrepresented compared to the rest, so that the highs never seem unpleasant or intrusive and recordings with too much high frequencies, as can be found in many new music productions with accentuated bass and high frequencies, are not annoying.
Super treble extension is flawless and apart from the peak at 5 kHz (that still remains below 0) I don't hear any peaks or sudden dips worth mentioning when sweeping.
The bass range can build up a nice bit of pressure and power and has a nice body, but it's not quite as fast as the one of the HD 800, yet it's more tactile and visceral with the LCD-X (the bass grumbling on some electronic music pieces with several parallel bass lines is quite appealing and also noticeable), although it doesn't have the same level of precision as the HD 800, where the bass decays faster and is tighter, more precise. However, the LCD-X bass is also miles away from slow and still tight, although not to the same degree.
Resolution:
The detail resolution of the LCD-X is high, but this doesn't necessarily become apparent on first hearing.
Although the LCD-X does not uncover bad recordings mercilessly, which is due to the lowered lower treble, it manages to display details finely, which it achieves not by emphasizing the upper frequencies, but by true resolution. At first, the Sennheiser HD 800, for example, seems to resolve better than the Audeze, but that's not the case: the HD 800 appears to have a higher resolution, especially in the high frequencies, which is due to the fact that it is somewhat accentuated here.
When switching back and forth and making longer comparisons, it is actually the LCD-X that reveals more micro details in the highs, but presents them more subtly due to the slightly restrained level in the middle and upper highs.
The qualitative difference to the HD 800 is really only minimal though and the LCD-X is only a razor blade's thickness ahead of the the Sennheiser.
What I find remarkable about the LCD-X is that, to put it mildly, it still makes bad recordings very audible and doesn't want to be an acoustic magnifying glass, which is due to its clever tuning to a high degree.
Old Led Zeppelin recordings, for example, are barely audible to me with my HD 800 since it just uncovers everything relentlessly, while the Audeze presents them wonderfully, without me having any problems listening to an album until the end, without feeling the urge to take the headphones off or get the CD out of the player first. This is certainly mainly due to the different sounding, because in terms of resolution I see the LCD-X, as I said, a tad above the HD 800, at least when it comes to the highs.
Spatial Presentation:
The stage of the LCD-X is rather small, but I still think it is well done, because it offers a good and authentic three-dimensionality with a lot of depth and a nice arrangement of the individual depth layers, and for me it is also more coherent than that of the HD 800, which I find somewhat strange in the representation of spatial depth, because it offers depth, but for me it is not really authentic and appears a little unnaturally layered and not deep enough in relation to the width, which doesn't stand out negatively in classical and electronic music and is even pleasant but might sound out of place/unnatural with jazz, pop or rock music.
What the LCD-X doesn't master so well is to convey acoustic emptiness between instruments. If, for example, there is empty space/large distance between instruments, you can hardly hear it on the Audeze, unlike on the Sennheiser, which presents it almost frighteningly precise and vacant, as well as a few of my higher-priced and custom-made in-ears.
Conclusion:
The LCD-X is a great headphone with a moderately bassy-dark sound and very high detail resolution, which you don't necessarily notice on first listening.
Although the headphones have a very high resolution, they are a musical palliator in the positive sense of the word and make even average recordings still sound good without masking details. You won't find a sonic scalpel that uncovers bad recordings mercilessly - the Audeze doesn't even want to be that - instead you get a musically yet balanced tuned headphone for the price with a nice bass body and good sweetness in the midrange, as well as an authentic sound that, in my opinion, can still deliver its best performance with rock music.
If, on the other hand, you're looking for a wide sonic stage, the Audeze LCD-X, which is rather intimate but deep and precisely layered, might not be the right choice for you. Of course you also have to consider the high weight of the headphones, which causes many people problems - previous testing is obligatory here.
Apart from that, I see the sound of the LCD-X on a par with that of the Sennheiser HD 800, with the latter playing more precisely and tighter in the bass range (albeit with a less linear extension towards the real sub-bass), which the Audeze, however, makes up for with the more perceptible bass body.
Both are good headphones, but their sound signatures also differ quite a bit (the HD 800, for example, has a slight v-shape tuning with a small hump that extends from midbass to the fundamentals and also has an emphasis in the upper and middle treble, whereas the LCD-X has a uniformly raised bass and fundamental range, as well as slightly reduced trebles).