By now I think that it is no secret that I enjoy tinkering around with different cables to see what, if anything, it does with the sound of my IEMs. Like a good little audiophile (read: hopeless addict) I tend to gravitate towards the more "up market" cables (read: Oh my God, it is so expensive!). My personal best achievement in this is wrestling with an insane $2,500 12-wire cable with the ergonomics of a garden hose. Needless to say that during this particular adventure I met my match and had to concede that perhaps I should take a small step back and make more sensible decisions in my life... Well, as sensible as I can be. Don't expect me to be buying a minivan or wearing a tie anytime soon. But the adventure did drive home the point that ergonomics are important to me. Especially when I travel or commute I tend to select gear based on how discrete it is to use and how easily I can store it away in a pocket or backpack. Even though I have a number of very ergonomic 4-wire cables, I still find myself using the tiny Final E2000 for commuting because they store away so much easier, even if it comes at the cost of sound quality. But then I would be sitting on the bus thinking... "Do I dare show myself in public like this?" "What if someone from Head-fi sees me??" "What if they make pictures?!?" Obviously a solution had to be found, but what would be the ideal solution? Among a number of thin, ergonomic cables, the PlusSound X-Series has attracted my attention the most often. No doubt because I am familiar with PlusSound's very ergonomic 4-wire Exo cables and I always wondered how good the 2-wire X-Series would be. Needless to say that when the opportunity presented itself to review one, I leaped at the opportunity to see if I could put it to the test and (hopefully) save my audiophile dignity on my next commute.
The X-Series cable came in the familiar satin black box with black sleeve around it that, apart from the nice glossy black artwork, contained information on the back about the cable, instructions on how to use and care for it and warranty details. Inside the box was of course the cable that was sealed in a clear bag (which I removed before taking the pictures because I was far too eager to have a quick listen first) and alongside a small box with accessories. The accessories are an amplifier band, a microfiber cloth, a cleaning tool and a leather strap to help organise the cable. I have addressed these in more detail when they were first released and I still think it is a very useful set of accessories, as well as a very convenient box.
Of course ultimately it is all about the cable and it looks gorgeous. In fact, I think this is one of the most beautiful cables I have reviewed so far. The new parts that I will discuss in more detail later, add a lovely bit of colour and for this cable the colour combination works especially well. The 2-pin connectors and 3.5mm termination are all black and finished with a gold cap, the y-split is also gold coloured aluminium with a black slider and those gold accents match the colour of the cable really well.
Build quality and ergonomics
Before this review I already had the opportunity to have a closer look at two other PlusSound cables, the Exo Silver+Gold and the X6 Tri-Copper, and I absolutely loved the build quality of those cables. The parts that PlusSound used were very solid and felt like they were built to last. Indeed, I used the rather silly term "utilistic" to describe the design, referring to the feel of the parts that gave me the impression of being purposely designed to be used and used extensively. The connectors and termination were quite chunky with a heat shrink cover that gave a solid feel to the parts when plugging and unplugging, and it made the cables a pathological cable-roller's dream. Since I can't ever just settle on one cable paired with my IEMs that would be me, and I greatly appreciated it.
For 2019 though PlusSound developed new parts to replace their trademark heat shrink, a somewhat risky move considering it was very much a part of what distinguished PlusSound cables. But as soon as I saw and started using the new parts, I realised that it was very much an evolution of the design. On the connectors and termination the heat shrink is now replaced by a cover that feels just as solid, but is a little thinner and has a coloured cap that works as a left and right indicator (although they can also be the same colour). For the termination there are four colour options, black, gold, silver and rose gold, while for the connectors there are two additional options with red and blue (often used to indicate the right and left sides respectively). The feel of the new cover is very similar to the heat shrink and it is still a dream to use when switching between cables.
The ergonomics while wearing the X-Series are fantastic and the cable generally just disappears completely. I did find that for some reason the cable is a little more prone to tangling and that can be a bit fiddly at times when removing it from a pocket in order to use it. However, I often just run the cable under a shirt when I am commuting to avoid it getting in the way or catching behind something when I move around and then I am completely unaware of the cable, it is that thin and ergonomic. Indeed, my commuting setup now consists of the Shanling M0 paired with the Custom Art FIBAE Black and of course the X-Series GPC. It is a great sounding and extremely musical setup, perfect for listening to some fun tunes while doing a dreary commute. Love it!
Source and IEMs
All listening was done with the Cowon Plenue 2, a neutral DAP, from the SE out. As synergy is very important with cable pairings, I tried a number of different IEMs. Because of the excellent synergy, the main impressions I give here were made with the Custom Art FIBAE Black and I will give more succinct impressions of additional pairings further down.
Every cable has general characteristics that might or might not work well with certain IEMs and I enjoy trying to find great synergy, because if the cable does pair well with IEMs the result can be incredibly good. So too with the pairing of the X-Series GPC with the Custom Art FIBAE Black. The X-Series GPC seems to take all the best bits of the Black and take it up a notch. The Black are very musical and dynamic with the stock cable and the X-Series GPC takes that to the next level and really emphasises the musicality of the Black. The pairing is so good that I consider it the most musical and engaging pairing I have around.
The X-Series GPC is a slightly warm and very natural sounding cable that increases the size of the stage (despite being only a 2-wire cable) and adds a nice amount of air. The image feels cleaner and more stable, which gives a greater sense of clarity. The overall transparency is improved and it makes instruments, vocals and even other sounds come alive even more than with the stock cable. Reverb is a great example here and I was very impressed by how well I could hear it when listening to Elin Manahan-Thomas sing Hildegard of Bingen. The music of this 12th century Benedictine abbess comes through so well with this pairing as the solo vocals bounce off the walls of the church where the recording was made, giving that feel to the music that only a church can give. In the same way my recording of Bach's Magnificat feels so much grander with this pairing because of how tangible the environment feels. This effect is something I put down to how well the X-Series GPC accentuates those specific strengths of the Black. It does not just work with classical music, but any music really. Everything I listen to sounds more dynamic and more realistic, like hearing it performed live.
That feeling of the music being performed live comes in no insignificant part from the bass that extends a little deeper and takes on a more analogue quality, although without losing the inherent speed of the Black's bass. The Black have a quick and agile bass that punches quite hard and precise, which is just as fast with the X-Series GPC, but punches even harder. When listening to the Foo Fighters' Cheer Up Boys (Your Make Up Is Running) the opening drums hit harder and just as fast, sometimes waking me up if I happen to have dozed off a bit while working behind my computer. The punches instantly get me engaged and although it might not have the effect of making me work harder, it does have the effect of making me dance while seated in my desk chair, which I think makes for quite an entertaining sight. That analogue quality also works great with the Rolling Stones and the kick drum in Hate To See You Go sounds just awesome, giving a bit of a dynamic driver quality to the bass of the Black's single BA driver.
The mids of the Black are quite natural to begin with and the X-Series GPC compliments that too. The mids become cleaner and more airy, while the tonality feels a bit more accurate with improved transparency to give instruments a more realistic texture. I love listening to Agnes Obel with this pairing, as the piano sounds gorgeous with a delicate feel to the notes that are accompanied by the slightly cleaner and stronger vocals of Agnes herself. Vocals indeed are a treat with the Black, and the X-Series GPC only further emphasises that for both male and female vocals. With choral pieces such as the previously mentioned Bach's Magnificat, this leads to better layering as an increasing number of voices come in and gives a more dynamic feel to the way the music builds up in scale. Female vocals have a crisp clarity to them, but with a hint of sweetness to make the soprano voices a little easier on the ears, and male vocals have that deep natural throatiness to them. Again, these are strengths that the Black already have, but that the X-Series GPC accentuates very nicely.
Like the bass, the treble gets extended a little further to add a bit more air to the stage and a nice, but still very natural sparkle. The difference is not huge and I really appreciate that because the Black have a very nice laid-back sound that I would not want to tinker around with too much. Still, cymbals get a little more sparkle without being pushed further forward.
One of the things I generally attribute to the treble is the bite in strings. Be it violin or guitar, if the treble is attenuated too much then the strings will lose some bite and crunch. With the X-Series GPC the Black give one of the best bits of crunch to guitar strings I have heard and it is one of the key factors in how engaging the Black are. I absolutely love it and it is pure pleasure to listen to the Stones or Santana with this pairing.
-Empire Ears Phantom-
The difference between the Phantom's stock Ares II and the X-Series GPC is very small and that is actually quite impressive seeing how the Ares II is a high quality 4-wire cable compared to the X-Series 2-wire configuration. The sound with the X-Series GPC is slightly cleaner due to a tighter bass and brighter treble, but that difference is very small indeed. Transparency seems to be touch better and the stage dimensions are very similar. I had expected a clearer difference, but this pairing shows that the X-Series makes for a great ergonomic alternative to the stock 4-wire cable.
-64 Audio Tia Trio-
This pairing is more clearly different and very much in line with the synergy between the X-Series GPC and the Black, the Trio really seem to work well with this cable. The sound become more punchy, the bass extends deeper and the treble is more sparkly, while the overall feel is cleaner and a hint more transparent. The musicality of the Trio is kicked up a notch and I really enjoy this pairing. It is exciting and musical with the great technicality of the Trio, making them very engaging and I love the deep bass this pairing is capable of.
-64 Audio U12t (M20)-
This is an outstanding pairing in my opinion and I really love it. The X-Series GPC adds a more full bodied bass to the U12t and warms up the signature slightly to become, in my opinion (based on my preferences) a bit more natural sounding. The U12t become more musical, rather than technical in their sound and the balance in the overall signature is more to my liking. It sounds like how I always imagined U12t could sound before hearing them, which is purely based on my preferences for a slightly warm, musical signature with outstanding bass.
The PlusSound X-Series Gold Plated Copper is a wonderfully ergonomic cable with great performance and has quickly become one of my favourite pieces of gear. It seems to pair well with different types of IEMs and even though it is only a 2-wire configuration, performs easily as well as premium 4-wire cables. Build quality with the new parts that PlusSound introduced this year is excellent and makes for a great option for those looking for a highly customisable and durable replacement for their stock cable.
Price: U$150 for the X Series cable, +$300 for the Hybrid wire.
First of all, the plusSound (PS) cables arrives in a simple yet elegant and hassle-free black cardboard box. The cable is packaged in a plastic back, and a rubber amplifier band is included along the information card.
As for the cable itself it is from the X series. These series are only available for IEM (any kind), and this we got the MMCX connectors with regular 3.5mm termination. The X series are the more affordable cables from PS and focus into bringing the best portability with a minimalist most compact and comfortable design. Yet, like the rest of the PS products, the X cable boosts high build quality and well put design. It simply consists of two main cables twisted together from the plug to the y-split and then separates into a single cable for each right and left sides.
The standard straight plug is large in comparison to rest of the cable and carries the whole weight of it; it’s very solid and tightly sealed by the heat shrink tube. The current y-split is 3D printed, made of acrylic and available in different colors (and can be also ordered in aluminum. The slider consists of a simple short heat shrink tube as well that just does the job.
Lastly, for this MMCX version the cable uses the new connectors made of black aluminum with a screw design. The quality is superb, well covered by the heat shrink plastic tube. The connectors are larger than the standard plastic made MMCX ones, but also much stronger and more durable for continuous use. The idea behind the screw design is to improve connection between the connector plug and the IEM, and in practice it has proved to work properly. In fact, trying to detach the cable is more difficult than usual; extra care is when removing the cable as for not to damage the MMCX IEM socket.
Now, for the featured Hybrid wire it is one of the latest addition of plusSound that mixes gold plated silver and copper 6 Litz wires in the smaller PS 26 Awg for better ergonomics. At a closer look it’s possible to see the two wires tightly twisted together inside the outer plastic transparent tube.
While the X cable might not look as tough as the 8-wire series, on the other hand it features a much more ergonomic and very comfortable fit. Microphonics are not an issue at all, and while not tangle-free it is still well behaved. It can be more springy than other cables, mainly next to 4-wire ones (2 per side) which can adopt a better shape around the ear, but nothing that a single pair of earguides cannot fix.
Getting to analyze the sound of the so called “upgrade” cables is no easy task and the differences/improvements are not always present. This is the second cable I got to try from plusSound company, and this time in a MMCX variation with many IEM models, from the low budget tag of ~$20 up to $400 ones. Just to mention some, we have the Westone UM 30, the LZ A4, the Shure SE535, Musicmaker Shockwave III, the last Vsonic iterations of the GR07, both the Classic and Bass 2017 MMCX versions, and finally the new Dunu's flagship DK-3001. Comparisons were taken against stock cables of all the IEMs, plus the Meelec and LZ upgrade cables, and some extra DIY silver-coated copper ones. Main sources used were the Fiio X5ii, Xduoo X3, PAW5000 and new Aune M1s.
The overall changes in signature that the hybrid wire presents is a mix of both wire types, silver and copper. Sound gets more lively but not necessarily more aggressive, and actually has a smoother transition between frequencies. The bass is stronger and yet smoother, with farther and noticeably deeper extension. Bass power is more impressive with a punchier impact and slight extra mid-bass emphasis carrying some more warmth to the whole lower-end. Even though, the bass remains well-layered, fuller and richer in texture. While speed is not affected nor improved, the decay feels more natural.
The midrange remains mostly unaffected in terms of distant, however, the added coloration can make the lower midrange a little less than neutral. Such is the case with the GR07 Classic and Shockwave earphones, where the mids take a little step behind giving a little more priority to the bass (and treble as well). Overall, the midrange is slightly more clear and detailed, neither too thick nor too thin, but more shows a more refined texture, especially for lower instruments and vocals. In overall balance, the midrange is not as aggressive as the bass and treble giving a more fun, ‘v-shaped’ presentation to the earphone.
The treble is more prominent and bit crispier, but less harsh and more controlled. If there’s sibilance, the hybrid cable won’t eliminate it, but at least it tends to be more tolerable at higher volumes. As with the bass, there’s also a bit of extra treble extension making the overall sound more effortless and accurate, yet more lively and somehow colored.
The presentation is probably the real strength on the Hybrid type wire. It has a better sense of space and separation with improved soundstage width and depth. It tends to sound less intimate so not best suited for vocals focused tracks, but it feels more immersive with a more natural and realistic timbre. If anything, there’s some sense of air and openness that is still missing for such a priced cable.
Getting the right source is important to show the changes made by the plusSound cable. With the new PAW Pico, there weren’t too much differences, however with the PAW5000, Fiio X5ii and moreover the Aune M1s, it’s easier to appreciate the real characteristic of the hybrid type cable and probably due cleaner midrange and more open overall sound that these DAPs provide.
While the X series cables from plusSound may be the lowered priced ones, there’s nothing cheap on them at all, boosting an excellent build quality mixed along with the better ergonomics for In-ear earphones. The simple cable made out of just to wires makes everything more compact and comfortable for everyday use. As for sound quality changes or even improvements, that would depend on the internal wire type chosen. The hybrid copper and silver wire asks for a higher price, but also make noticeable changes on the overall sound. plusSound describes the signature of this wire as being warm, detailed and having a better stage, and from the different earphones and sources used, that description is very accurate.
Pros: great value, excellent workmanship, noticeable refinement in sound.
Cons: sound improvement varies depending on pair up with different sources and earphones.
The product was provided to me free of charge for the review purpose in exchange for my honest opinion.
Manufacturer website: PlusSound. My general thoughts about replacement cables (cable review intro).
Aftermarket premium replacement cables have been a controversial topic of discussions in many audio communities. There are some who don’t hear a sound improvement and others who consider the improvement to be too subtle to justify the cost. Some are firm believers (myself including) who do actually hear the change in sound, while others talk themselves into believing to validate their purchase. I also ran into a group of people who consider cables as another accessory to personalize the appearance, just like they would with CIEM customization, or those who switch from single ended to balanced and take the opportunity to upgrade to fancier wires. And then you have a group who never tried a replacement cable and formed their opinion based on reading someone else’s rant.
From my personal experience, I do hear and feel the change in a sound, but I'm not able to capture it accurately in measurements. The most obvious change even disbelievers can agree on is that higher purity material will yield a smaller resistivity, better conductivity, and corresponding boost in signal level. Also, various metals have different properties. There is no magic behind it and you’ll get an instant benefit of slightly higher output driving your transducers, something that could be measured. But when I hear a change in bass tonality, tightness, articulation, or I hear more airiness in treble or overall improvement in retrieval of details which feels like a layer of veil is lifted off – this is not easy to capture. Considering we all have a different perception of sound, without supporting measurements some people jump into conclusion and form a “snake oil” opinion, especially when price is taken into consideration.
The intent of this review is not to change anybody’s mind, but rather to share with you what I hear and how I hear it. Perhaps, I can’t fully explain why there is a change in sound, but I do hear it and would like to describe it. What makes sense to me is that I look at the wire as a material with physical properties of resistivity, conductivity, level of purity, etc, which acts as a filter between your source and headphones. Variations of these physical properties will affect the electric signal and result in a sound change, from a subtle to a more noticeable level. Also, I want to talk about the design of these cables, to make people understand why they cost so much, and that you are not dealing with a “coat hanger” wire but rather high grade materials, advanced production techniques, and hours of labor which all add up to a premium cost. Last but not least, the sound improvement of one particular cable is not universal because it will depend on the synergy between your source and your headphones.
Founded less than 4 years ago, Plussound is a relatively young company, but they are very ambitious and I constantly see Christian (the man behind the company) actively participating and offering suggestions and support in many different threads on Head-fi.
While communicating with him through PMs, I always had a prompt reply within an hour. He was very honest and straightforward with me about his current workload and how long it will take him to make a cable. Custom cables are often made to order, thus do your homework about cable-maker before moving forward with a purchase - it’s almost as important as choosing the cable itself.
Regarding the material used in his cables, Plussound offers a number of signature copper, silver, and plated wires described in details here. One thing you going to notice right away is that regardless of the type of cable material, they all feature a Type 6 Litz configuration where wires have 6 enamel-coated groups with multiple strands to decrease electrical anomalies (such as skin and proximity effect causing microphonics), to minimize oxidation (preventing wires turning green), and to improve conductivity (electric signal usually travels on the surface of the wire, thus multiple thin strands will have a better conductivity and a smaller resistivity than a single “coat hanger” wire).
Another important fact is that Plussound wires are cryogenically treated for strengthening purpose to enhance their reliability and longevity. Furthermore, the wires itself are UP-OCC manufactured, referring to Ultra-Pure Ohno Continuous Casting process developed and patented by Professor Ohno of CIT in Japan. Also, many of Plussound cables have an option for a custom sleeve between the y-splitter and the plug. When I first saw it in the pictures, I assume it was for decorative purposes until I learned later that it’s a rather advanced multi-dampening system featuring tri-shielding and dual insulation for a better isolation of wires from outside environment and from internal interference all the way down to the plug.
I know that for many people all these buzz words and tech terms doesn't mean too much; after all, the majority will only care about the final performance and the overall appeal. But I often hear a question why aftermarket cables cost so much. You have to take into consideration the cost of the pure copper, silver, gold, and the weight of corresponding wires when you are dealing with multi-braided cables. There are also other contributing factors, including manufacturing process (UPOCC), additional treatments (enamel and cryogenic), engineering (custom shielding), labor of braiding and twisting, and choice of different plugs and shell connectors.
I still look uneasy at the cables that fall into $600-$1k price range. I do hear the improvement in sound over the stock cable, but the higher the price the deeper you are into the territory of diminishing returns. After my review of their X8 and Apollonian+ series cables, Plussound approached me with an opportunity to look into their “entry level” X series, and I actually got curious how their budget cable going to perform. Due to my review schedule it took me a little while to get to this write up, though I have already been talking about this cable in some of my posts on Head-fi.
As I mentioned in my other Plussound review, while majority of cable manufacturers pay little attention to the actual packaging and send the cable in a padded envelope, I was pleasantly surprised to receive Plussound cable inside of a giftbox quality cardboard black box with a magnetic flip cover. It was a nice touch to see a branded logo on the cover top and the sides, as well as "Handcrafted in the USA" printed on the front. Inside, the cable and the included adapter (optional right angle 2.5mm TRRS to 3.5mm TRS) were sealed in individual clear plastic bags and foam lining was used for extra cushioning. Also, I found a bonus branded rubber band and Custom Cables card with lots of interesting details about the wires, components, installation instructions, care, and warranty.
I do recommend reading this card because it actually has some useful info, like mentioning about the shell connectors with locking screws relative to L/R position where screws have to face outwards. You can request to customize the housing of L/R connectors with a color coded label, but in the dark it's easy to feel the position of these screws for a “blind” guidance.
X series Plussound cable doesn’t look like your traditional multi-braided heavy cable. It’s actually part of their ultra-portable series which is lightweight and intended for traveling and stage use. Anybody on the move can benefit from these thin (1.4mm) 26AWG gauge wires where only 2 twisted cables are used. For my review purpose I choose a tri-metal wire blend with copper, silver, and a small amount of gold - the option which raises $125 X series baseline price to $199. Various wire materials have different conductivity and resistivity properties, and as a result the hybrid mix usually takes advantage of the combined performance.
Upon closer look you can actually see the bi-color UPOCC enamel-coated litz wires within each cable surrounded by clear PE insulation shielding. As Plussound stated, all these wires are cryogenically treated to strengthen their structure. Even so wires looks thin, they feel very durable. Also, not only the wires get cryo treatment, but according to Plussound all of their anodized aluminum components such as plug and shell connectors, y-splitter, and chin sliders also get this treatment to increase the strength and durability. On top of that, connectors can also be customized with a different color print of the heat-shrink tube exterior. Having this rubbery coating on top of the connector, which also extends and forms a strain relief, makes a nice non-slip grip. But at the same time it also makes connectors look a bit DIYish.
The design I received didn’t come with a chin slider, though you can add it when customizing your cable with different available options. Since the wire is thin, lightweight, and supple, it doesn’t really require a chin slider assistance to bring the cable wires together in order to keep it tight behind your ears. Another interesting feature of these cables, found in other Plussound cables as well, there is no memory wire and instead the cable is pre-shaped like an earhook. I have no idea how they do it, but this type of “invisible” earhook looks very clean and does a good job in keeping wires secure around your ears. Also, I found the cable to be easy to wrap for storage and it stayed tangle free. There was hardly any microphonics, and the memory effect of the cable was down to minimum.
Since I have many different DAPs with both 3.5mm TRS and 2.5mm TRRS connectors, I asked for the cable to be terminated with a balanced 2.5mm TRRS connector and also received an optional ($75) custom made right angle adapter. In my previous review I had a straight one piece adapter, while here I wanted to take a closer look at their angled one. It’s all a matter of a personal preference, but usually straight adapter works better with a top mounted HO while angled one is more convenient with HO at the bottom of the DAP. Either way, it’s a one piece adapter, very well built, and convenient to use with any 2.5mm balanced cable without adding extra length or bulk.
Last, but not least, I couldn’t help but notice this X series tri-metal cable was nearly the same thickness and weight as Linum SuperBaX cable. SuperBaX is not as thin as a regular BaX, but in my opinion it’s in the same category as X series. I wasn’t able to compare their performance since my SuperBaX prototype has mmcx connector while X series is 2pin, but in side-by-side comparison fully loaded tri-metal X series is cheaper than SuperBaX and comes with lots of customization options in comparison to a more expensive SuperBaX which can't be customized.
Right angle 2.5mm TRRS to 3.5mm TRS adapter.
Next to Linum SuperBax.
For this test I used Lotoo PAW Gold (SE only connection) and Opus#2 (SE and BAL) as a source for testing and comparison. Prior to testing, I kept the cable on a burn in for about 100 hours. When I was switching and comparing cables, I made sure to volume match the sound level by ear. In general, I found this hybrid cable to offer a smoother full body sound refinement with a nice accentuation of low end frequency range. In comparison to a typical stock OFC, it also lifts a veil off the upper mids and lower treble, though don't expect the same level of bright revealing sparkle as you would get from pure silver or gold-plated silver wires.
Here in more details how it sounds with a number of selected IEMs/CIEMs after I switched to this X series cable.
UM Maestro (stock ofc vs X) - sub-bass extension goes deeper with a little more quantity, mid-bass punch is slightly stronger, and overall bass is tighter. Upper mids are a little warmer, more organic, and less splashy. Treble is a little smoother, still crisp but with a bit less airiness. Strangely in this case I found the connection with a recessed shell of Maestro to be not as secure.
Noble Savant (stock spc vs X) - upper mids/treble becomes a little smoother, otherwise a very similar sound. 2pin connector fit was a bit tight.
Noble K10UA (stock spc vs X) – nearly the same sound. Tight fit of the connector, but not as much as Savant.
CA Ei.xx (stock ofc vs X) – I hear more texture in sub-bass, a little more impact in mid-bass and overall bass is tighter and better controlled. The most noticeable change is in upper mids/treble where the sound becomes brighter, more detailed, treble is crisper and with more airiness. Overall, the sound becomes more resolving and has improved layering effect. I was previously using BaX with Ei.xx, but I think I prefer X due to more airiness and higher resolution.
CA H8.2 (stock ofc vs X) - bass is tighter, the same quantity but feels tighter and a little faster. And just like with Ei.xx, you get a brighter upper mids with improved retrieval of details and crisper treble with more airiness. This also improves the perception of the sound which becomes more resolving and with improved layering of instruments and vocals. I found this pair to be very good, even better than some pure silver or pure copper cables.
InEar StageDiver SD4 (stock ofc vs X) - in my original SD4 testing I had to use ofc cable and Comply foam tips to tame down the brightness which made sound smoother but also lost some airiness and details. X brings back the missing details while still keeping the sound in a comfort zone without pushing it toward bright harshness. I do hear low end being a little tighter and better controlled, but the most significant improvement is brighter and more detailed upper mids/treble without analytical sibilance. Tight secure recessed socket connection as well.
64Audio U12 w/B1 and UE Buffer jack (stock vs X) - not a very significant improvement, but I do hear bass being a little tighter and more controlled (better separation from lower mids), and a touch more sparkle in the treble. With U12 the most significant sound improvement is switching to Buffer jack.
EE Zeus-R (stock BTG spc vs X) – I hear a little less hissing. Bass is nearly the same, while treble has a touch less airiness, becoming a little smoother. The biggest change is in mids where you get a little more body in lower mids and upper mids become a little more organic and slightly warmer. You still have the same slightly mid-forward signature, but now the sound has more body. Great pair up if you want to smooth out Zeus signature and cut down on some hissing.
Unlike some other more expensive alternatives, Plussound X series cable is very easy to recommend because it's lightweight, durable, looks great, offers a noticeable improvement in sound, and very reasonably priced. I definitely hear an improvement in sound quality over the typical stock OFC cables, though the level of the improvement will vary depending on the pair up synergy between the source and IEMs/CIEMs. In some cases, for example with Noble and their own SPC cable, I didn't find too much of an improvement, but in other cases the sound refinement was quite noticeable. As I said in my previous cable reviews, it's hard to have an objective opinion about sound improvement when upgrading the cable because we are not talking about a sound signature change or anything that drastic, but rather a level of refinement which has a subjective perception. That's why sometime it's not easy to recommend $500+ cables, but in case of X series with this particular $199 tri-metal model - I can go even as far as saying it offers a very reasonable price/performance ratio.