PLUSSOUND Prism Universal In-ear Monitor

General Information

Full Sound

PLUSSOUND Prism consists of two USA-made balanced armature drivers (one for high frequency, one for low frequency) that provides a warm low end with extended highs.

3D Technology

Drivers are housed within a thick diameter enclosure that was designed by us and manufactured in-house using medical grade 3D printers. Earphones are made out of durable hypoallergenic acrylic material and hand brushed with special coating to provide scratch resistance and sleek surface.

External Design

Designed to be stylistic, yet ergonomic.
This design allows for the user to wear the cable either behind ear for critical listening or hanging down for other activities. Measuring at just 27x11mm, it offers excellent comfort and fit.

Internal Design

This unique earphone features a single 3D printed horn shaped waveguide for a more open and detailed sound. As well, an added driver and damper shock mount were designed to prevent movements from ever affecting sound quality and performance.

MMCX Connector

Prism features a special MMCX connector developed just for our IEMs. Made from copper based metal in gold plating that offer a significant improvement in tensile strength and substantially reduce signal loss and ensures maximum performance.

UP-OCC Internal Wiring

Drivers and connector are only few millimeters apart and joined together using our well regarded UP-OCC wiring. The micro signal path provides consistent conductivity and sound quality.

Exo Cable

Included with every earphone is our popular Exo cable featuring a new 28AWG Copper Type 6 Litz wiring. Made exclusively for our IEM lineup, the wire is soft, flexible, and durable. Improvements in clarity and detail are present. MMCX connectors are made from same material as the earphone connector for optimal durability and reliability. You can also select termination from available options that best suits your needs.

Comply Foam Tips

We have partnered with Comply to provide the best fit and comfort when using our earphones. Prism comes with Comfortand Isolation and includes small, medium, and large sizes.

Hand Built in USA

Both the earphone and cable are assembled in-house in Los Angeles, California, USA to provide the best quality and sound experience possible. One year warranty is offered on both.

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Latest reviews

Pros: Warm, Detailed, Accessories
Cons: Extension

Plussound is a company from California, USA and specializes in producing custom cables for in-ear monitors. They have started out on their own iems – Spectrum, Prism and Gamut. In this review, I will be reviewing the Plussound Prism which is a dual balanced armature iem – 1 for the high frequency and 1 for the low frequency. I would like to thank Plussound for this review unit. The unit I will be reviewing is black in colour. At the moment, you can purchase the Plussound Prism from .

Unboxing & Accessories

The Plussound Prism comes in a nice black package that has the Plussound logo at the front. After opening the package, I see 2 metal tins – 1 is black in colour and 1 is silver in colour. In the silver tin, there is the iem while in the black tin, there are a Plussound card, Comply care instructions manual, 2 packs of T-500 Comply foam tips (S&L) , 3 packs of TS-500 Comply foam tips (S, M & L), 1 MagicFiber cloth, 2 stacking bands and 1 cleaning brush.

IEM Build & Design

The Prism has a glossy black surface to it and it is circular in shape. On the back of the iem, there is “PS” logo printed on it. The shell is made out of an acrylic material. It is rather light weight. There is a silver vent on each side of the iem shell. The nozzle is straight without any mesh. It is quite long. There are no L & R markings on the iem to differentiate between left and right. It utilises mmcx connectors. The Prism is manufactured using Plussound’s in-house 3D printers. There is good build quality to it.

Cable Build & Design

The Prism comes with the Plussound Exo 28AWG Copper Type 6 Litz cable. It is not the usual stock cable but an upgrade cable. The build quality on the Exo is of a high standard. It is soft and flexible. On each of the connector, there is a Plussound logo in blue and red to differentiate between left and right respectively. Moving down, there is a rubber chin slider and a y-splitter. Lastly, the jack is 2.5mm balanced gold plated. It has a rubber-like protective cover on the jack housing and it sports the Plussound brand name in green colour.

Sound Analysis


The Prism has a good sub-bass extension with an average rumble. The mid-bass is laidback and soothing. Some may prefer more slam for the extra punch. The bass is tight and controlled. The decay is average and the bass note is being presented smoothly. I find the Prism to be warm and smooth. The nature of the bass leans towards the slow side and music takes on a less exciting approach. The bass texture is rendered very smoothly and it is still clean. The bass helps to boost the lower mids.


The midrange is quite balanced and the presentation is leaning towards the smooth approach. The lower mids on the Prism has quite a good body to it and the amount allows male vocals to be rendered effectively. The upper mids are slightly forward but there is a small amount of veil that restricts the vocals presentation. The definition on the midrange is quite good. Although it may not be the most detailed, I feel the Prism showcases details rather well. There is good balance of musicality and technicality. The midrange is smooth and warm with only the upper mids not providing the extra bite for liveliness.

The treble is extended rather well with a good linear presentation. There is no sibilance and harshness. There is no graininess and it is presented very smoothly. The crisp is rather decent and I feel with a slight sparkle, it will help to energise the overall presentation. The air at the top end has a good amount and it helps to prevent the sound from being too congested. The clarity is quite good with an above average details retrieval.


The Prism tackles both aspects of soundstage well with a good width to aid the vocals and instruments positioning and prevent congestion. The depth is not too close in and there is space for the presentation. I find the Prism to have a surround feel.


Plussound Prism vs Noble Sage

The Prism has less sub-bass quantity and extension than the Sage. The Sage has the advantage in its sub-bass reproduction and it is slightly more superior in the quality. The mid-bass on the Prism is more controlled. This allows the Prism to excel in tracks with less pace. The Sage has a more engaging slam. The bass texture on the Prism is being rendered with more finesse and smoothness. The bass note on the Sage is slightly more accurate with a faster decay. The bass control on both is very similar but the bass nature is different. The Sage has slightly more body in the lower mids department and male vocals are expressed better. For the upper mids section, I find the Prism to be more controlled in presenting female vocals but there is a slight restriction as compared to the Sage. At this point, it depends if you prefer a smoother or exciting approach to your sound. Next, in the treble section, the Sage is being expressed with better articulation and extension. There is no sibilance and harshness on both. The amount of air rendered is similar and the Sage has extra sparkle. In terms of soundstage, the width on the Sage is slightly better but the depth on the Prism is not too closed in. Vocals and instruments positioning is more precise on the Sage. Both are not congested. Resolution on both is approximately the same.

Plussound Prism vs InEar StageDiver 2

The Prism sub-bass have more quantity but does not extend as deep as the SD2. On the SD2, it is slightly more clinical and refined. The mid-bass on the Prism has a heavier weight in its note while on the SD2, it is more pacey. The decay on the SD2 is faster. The bass nature on both is different. Prism presents the bass in a warm and smooth way while the SD2 has the clinical edge in its bass reproduction. The lower mids on the Prism has more body than the SD2 and it is thicker as such. Male vocals are presented better. The SD2 is dry and less engaging in this aspect. The SD2 has slightly more forward upper mids than the Prism and with the added crisp, the vocals performance is more organic. Female vocals sound sweet here. In the treble section, the SD2 has more air and sparkle while the Prism is more smooth at the top end. SD2 has the extra bite which makes its treble stand out. Treble articulation on both is quite precise and the details retrieval is good. I feel it depends individually as both operates on different approaches. For the soundstage, SD2 has similar width as the Prism and Prism wins in the depth. Layering and separation on both is very similar. The resolution on the SD2 is slightly better.

Plussound Prism vs CTM VS-2

The sub-bass quantity on the Prism is more than the VS-2 and it has better extension. On the Prism, it has slightly more definition in its bass reproduction. The mid-bass of Prism has slightly more weight and authority. Bass texture on the Prism is rendered with more finesse. I feel each bass note on the Prism is presented with more control. The lower mids on the Prism has more body and it is thicker. The VS-2 is slightly more forward in the upper mids and it sounds more organic at the top end. The details retrieval is very similar. For the treble section, the VS-2 has slightly more air than the Prism and clinical in its presentation. There is no sparkle on both. In terms of soundstage, the Prism has the edge in both width and depth. Vocals and instruments positioning on the Prism is more accurate. The resolution on the Prism is better.


The Prism is a dual balanced armature iem in Plussound iem lineup. It provides a smooth and warm sound that one can listen to for a long listening session. Furthermore, resolution is great with a high standard of details retrieval. There are many accessories and the iem comes with an upgrade cable. I enjoyed listening to the Prism.

For more reviews, visit .
Pros: Layering and Separtion
Sounds Alive and Fun
Cons: Detail Retrieval

The PLUSSOUND Prism is made in the California and features two balanced armature drivers-one low and one high. It is the middle shelf offering from PLUSSOUND. The body of the IEM was 3D printed using hypoallergenic acrylic. I actually thought they were metal because the coating that is applied to them is so tough and durable it gives them a metallic feel. The housing is very small for a dual driver IEM. A 3D printed horn shaped waveguide creates the spacious and high definition sound of the Prism. An added driver and damper prevents movement and shocks from affecting sound quality. Sturdy gold MMCX connectors and a 28AWG Copper Type 6 Litz cable round out the Prism’s presentation. High quality UP-OCC wiring is used internally. A variety of comply tips are included along with a small metal carrying case.

Sound Analysis


If as an audiophile you’ve ever been at a live concert and you listen carefully to the sound you will notice that it isn’t bright. It’s warm and dark, of course this changes with environment but on the whole natural concert sound is warm and dark. So is the Prism. When I’m listening to some excellent rock music like the 100 Watt Vipers – Cold Sunday Blues, the dark background combined with warm and massively dynamic sound of the Prism creates a “live effect” wherein the music sounds larger than live, powerful, rich and organic. The overall signature is mid centric and warm with an emphasis toward the lower-mids. The Prism’s background is utter blackness, against this blackness the 6k-20k frequencies standout.


The stage is wide, and tuned with great separation and layering. It’s more of a wide stage than it is 360. It isn’t the largest stage I’ve heard but it’s plenty large enough for me, what makes it exceptional is the space between the players and the instruments which allow for good image solidity and separation.

Resolution and Imaging

The detail retrieval is very good for the price point but falls short of the top tier $2000-$3,000 IEMs in the market today but that should not be held against the Prism. This is largely due to the Prism’s laid back and relaxed presentation.


A top of the line transparent headphone should be free of distortion and have a natural tone. These two things among other factors create transparency. Tuning for transparency is often a balancing act between dynamism and naturalism. The Prism is fully in the dynamic camp and it sounds great. If you want an IEM that has a warm, dynamic, smooth and live sound similar to hearing a concert in person.

Layering and Separation

Separation in the horizontal plane is very good with a lot of spacing between instruments and players placed in the X axis next to each other. The separation and layering capabilities of the Prism rival my IEMs that cost 5x as much. Image stability is very good as is image isolation, images maintain their space and shape during complex passages or passages in which quiet sounds are contrasted against louder sounds.

High Frequencies

The Prisms favor the 6-20k region much more than the upper mids, owing to the lower mids being elevated over the upper mids. Extension in the 6-20k region is spectacular and tone is realistic and natural. Layering and separation is exceptional in the highs due to the dark black background of the Prisms.

Middle Frequencies/Vocals

The mids are relaxed with the low mids being elevated slightly above the upper mids. Vocal placement is pretty close to the center of the head with the instruments positioned slightly further out. The mids are very smooth and laid back yet detailed. The resolution isn’t spectacular but it’s on par for the price point.

Low Frequencies

The Prism favors mid bass over sub bass. The bass isn’t chameleon like, it will sound the same no matter what genre you are listening to, the Prism can handle any genre and doesn’t lose its’ presentation when doing so. Decay is tight and resolution is good but not exceptional. I don’t find myself needing more bass with hip hop or electronic music, the Prism has plenty of bass for me. The bass coming from the prism isn’t so much visceral or felt, it’s more audible. The mid bass bump tends to make male vocals sound more powerful than female vocals.


I found the Prism’s to be very ergonomic and comfortable with the supplied comply tips. Others have reported the earphones falling out from time to time but I have a very tight seal and have not experienced any falling out. I did not wear these over the ears but also did not find them uncomfortable when doing so, I do get a very deep insertion though due to the shape of my canal. I never had any trouble getting a good seal. Noise isolation is very high with these, at work I had to keep my volume pretty low so that I could still hear the phone. The cable was very tightly attached and I feared I would break it by pulling so hard but for the purposes of this review I had to swap cables from time to time. I am happy to report the MMCX connections do eventually loosen over time. The cable has heft to it but I found it to be extremely comfortable and never had any issues using it.


I found the Prism to pair nicely with all my sources; Chord Mojo, S7 Edge, S8+ and the ALO CDM. It was readily apparent to me just how transparent the Prisms are when changing sources as they’re sound is dramatically affected. On the CDM they were punchy, deep, dynamic and spacious while on Mojo they were smooth, organic and sounded live. S7 Edge made them sound clear as well but with less detail and smoothness than the CDM or Mojo. They sounded great with S8+, big, dynamic and detailed but again they lacked the smoothness of analog signal such as that from the CDM or Mojo.

Suggestions For Improvement

I always try to find improvements no matter how minor. The midrange was a bit flat for my tastes but that doesn’t mean it isn’t detailed, spacious or well separated. I just prefer a more forward midrange. I didn’t like the pairing with the stock cable. The upgraded cable is much better as it removes the lower midrange bump, makes the entire sound more balanced and increases detail in the upper midrange and highs.


The Prisms are extremely well built IEMs. They are warm and dark with spectacular layering and separation. The mid-range is relaxed, the treble extension is spectacular, bass is authoritative and punchy. The Prism is a great value at its’ current price.

Pros: Fantastic cable, Great comfort and isolation, Balance, Separation, Bass definition, natural high end
Cons: Might be too laid back for some, Upper midrange isn't as detailed as competitors
Introduction –

When cable manufacturer ALO branched out into Universal earphones as Campfire Audio, they were met almost exclusively with success; Campfire has very quickly become a hugely popular and discussed brand. And hot on their heels is Plussound, a similarly experienced cable manufacturer who seek once again mix up the game by utilising cutting edge technologies and a keen eye for attention to detail. Plussound have released 3 in-ear models, all with unique, in-house designed balanced armature drivers topped off with their signature Exo-series MMCX cable. Let’s see if Plussound’s new offerings can reinvigorate the audio community like those before.

Accessories –

The Prism comes within a solid box with textured Plussound branding. The box is otherwise featureless without any indication of specifications or features. The box opens magnetically to reveal two altoid style tins, a black tin containing the accessories and a silver tin containing the earphones themselves.

Plussound include a delightful assortment of genuine Comply foam tips, 3 T500 tips and 3 sets of rounded TS500 tips, one pair of each in every size. Comply foams are great tips that provide excellent isolation and comfort, almost guaranteeing a solid fit regardless of ear shape though they do degrade after time. Unfortunately, no silicone tips are included though the Prism’s tuning is better suited towards the slightly warmer Comply’s anyway. Plussound also include two AMP/DAP stacking bands and a magnetic cleaning tool which is pretty nifty.

Overall, the unboxing isn’t lavish or quite as comprehensive as Dunu’s accessory suite, though the whole experience is thoroughly functional. I would perhaps like an additional carry case of some sort, I am concerned that the metal tin may scratch the iems though it’s a protective solution during travel.

Design –

All of Plussound’s new models utilise the same 3D printed housings. When compared to online readers, the earphones are larger than I expected though they are still considerably smaller than the 64Audio and Campfire Audio earphones. They feel simultaneously rock solid and handcrafted, courtesy of a hand finished paint job and the inclusion of Plussound’s signature EXO-series iem cable from factory. The Prisms are available in black and blue with a colour matched y-split on the cable. The black model looks more co-ordinated since the 3.5mm plug is always black though the blue model is tasteful enough for those tired of monochrome.

The housings are plastic but feel impeccably constructed; the 3D printed earpieces have absolutely no joins or seams. The earphones have quite an interesting design that is akin to Etymotic style earphones albeit larger. The housings are transparent and the plastic moulding is incredibly thick; Plussound have traded compactness in favour for superior acoustic properties. The earpieces have a hand painted gloss coat that gives them a super smooth, but slightly inconsistent finish. Small features such as the small bolts on either side of the earphone produce a very utilitarian look like that achieved by the armature based Campfire earphones and offer enhanced repairability should components require replacement or repair.

In use, the Prisms are an ergonomic earphone that achieves great long term comfort. The housings barely contact the ears at all with minimal outstanding features to cause discomfort. They were designed for a cable down fit and though their laterally placed strain reliefs and thick cable make them a bit awkward when worn over ear, it is doable. Due to the weight of the cable and their very lengthy housings, fit stability is just average; even with foam ear tips they wiggle themselves loose during any activity but walking. They definitely don’t lock into the ears like the Dunu, 64Audio and Campfire iems but they will be vastly more comfortable if you have smaller ears, a fair trade-off unless you intend to use them for running or stage monitoring. I found them far more practical to wear than either the 64Audio U3 or Dunu DK-3001, both of which are a bit strangely shaped.

The Prisms have a long, straight nozzle that fits wide bore tips. This does limit fit depth to some degree though they are a very well sealing earphone overall. The Prisms are also fully sealed and when combined with those thick housings and reasonably deep fit, passive noise isolation is terrific, few earphones provide more. With great isolation and comfort, the Prisms are ideal for any kind of travel though the long housings do protrude quite a bit from the ear, creating above average wind nosie during commute.

The Prisms possess a removable cable that uses the tried and tested MMCX interface. The connectors are super tight and secure, I didn’t experience any accidental detachment nor any intermittency in my month of testing. The cable receives special mention since the Prisms come packaged with Plussound’s $200 EXO-series custom cable. While I only have a handful of cables at this price, the EXO is definitely one of my favourites.

It’s a 4-core braided OCC litz copper cable with robust but not unwieldy thickness. Aesthetically, the cable is gorgeous with a very professional construction and finish. The cable also doesn’t tangle at all but remains compliant enough to coil and pocket. It is a bit stiffer than the Effect Audio Ares II+ though the Ares is also a little more prone to tangling. The EXO cable has well finished but very DIY terminations; the MMCX connectors and plug are covered in heat shrink and the cable is secured via small screws which are visible from the exterior.

The y-split has the same construction as the earphones themselves though the finish of the cable on a whole is still less compelling than the EffectAudio cables that sport custom metal/carbon fibre connectors. A chin slider is implemented in the form of some plastic tubing. It’s simple but gets the job done, I found it to hold its place reliably in daily use. Plussound claim to have implemented some sort of shock absorption into the cable to prevent microphonic noise though I didn’t notice the Prism to be any quieter in that regard than a typical cable down earphone. This is easily alleviated by wearing the earphones over-ear or by using the slider or shirt clip.

Plussound offer the cable with a variety of plugs at no additional cost, they also offer a balanced variation if your source can take advantage of it.

Sound –

The Prism is Plussound’s mid-tier earphone, featuring two of their proprietary balanced armature drivers setup in a low/high configuration. It’s a very special sounding earphone that has some really intriguing characteristics that I rarely hear from any earphone at any price. It’s interesting to see how the properties of Plussound’s fabulous cable augment the Prism’s sound without characterising it and it’s great to see that the Prism’s themselves are transparent enough to take advantage of that. It was definitely interesting to listen to an earphone that includes a custom cable from factory as the Prisms sound is greatly influenced by the effects I typically expect when installing such a cable. Most notably, the Prism is super clean and separated with a dark background, easily the most unique aspect of this earphone’s sound.

In terms of tip choice, the earphones aren’t super tip sensitive though foams are well suited towards their more neutral tuning, providing a little extra warmth and taking the edge off their balanced armature treble. Silicone tips fit fine, wide-bore dual flange tips are best suited towards the Prism’s long nozzles though sonically, the silicone tips sounded too lean to my ears. For my preferences, I opted for the pre-installed T-500 Comply tips, all impressions below will be with those ear tips.

Tonality –

The Prism is a reasonably mellow, perhaps slightly mid-forward earphone that finds good overall balance. Hints of additional bass impact and upper treble presence imbue the sound with character and engagement without compromising transparency. Otherwise, the Prism is a very linear earphone that provides a more musical evolution of the very neutral tuning found on earphones like the Hifiman RE-600.

Drivability –

The Prism is a sensitive earphone though not outrageously so. Plussound don’t provide any specifications on their earphones though their sensitivity is pretty similar to the Dunu DK-3001 (110dB), meaning they will reach ear-splitting volume from almost any source. They also pick up a reasonable amount of hiss, slightly less than the Dunu’s but more than most earphones making a clean source important. Their transparency makes them quite source sensitive and they clearly take on the characteristics of the source they are being played on. I did not find amping to be necessary though it does help alleviate output impedance issues and hiss. The Prism found best synergy with my Oppo HA-2 and Fiio X7, both of which provided a little extra clarity to the Prism’s sound. Strangely, the I didn’t find myself enjoying the Prism with more musical sources like the X5 III and Mojo, mostly due to their midrange and high-end which both benefit from a slightly brighter source.

Soundstage, Imaging and separation –

It was with their soundstage that the Prism immediately represented the benefits of that fabulous cable. But not in terms of sheer space, the Prism, isn’t the largest earphone I’ve heard, not by a long shot. Rather, their imaging and separation is fantastic with a clear advantage over similarly priced earphones. The Prism is actually a reasonably intimate earphone, even songs with encoded soundstage detail are mostly inside the head though they never sound congested; they have just enough space to craft a convincing stage. Their stage is quite unorthodox, it’s more depth focussed and height, which is usually entirely absent from a lot of earphones, is exemplary. Imaging is also terrific and the earphones can achieve an almost holographic quality when listening to the right tracks. Separation is also fantastic, especially considering the type of tuning these earphones pursue. The Dunu DK-3001’s make for great comparison as an earphone that pursues the opposite sort of presentation. The Dunu’s are considerably larger, achieving an out of the head sound far more frequently. They are also more rounded between width and depth but lack the height of the Prism. Imaging is great but lacks the precision of the Prism and separation, despite the added space and more dynamic tuning is just comparable. While not the most spacious earphone, the soundstage on the Prism was one that I enjoyed immensely.

Bass –

The Prism’s have quite a neutral bass response augmented by a little extra mid-bass punch and deep-bass impact. The Dunu DK-3001 and 64Audio U3 both produce more bass quantity, the Dunu especially so, though the more neutral Campfire Nova’s are quite similar in both tuning and quantity. While all are tasteful and incredibly well-done earphones from experienced manufacturers, Plussound’s offering is easily comparable in terms of both tuning and quality. Bass is incredibly linear, consistent between tracks and completely lacks bloat, spill or any form of muddiness. The low-end is very tight, I would describe it as snappy rather than rhythm based, though it’s a performance that fits in very well with the rest of the sound. Bass is also very textured with high resolution throughout and the earphones have no issue dismantling complex passages. Some may find the Prism a little too lean, they definitely require some adjustment when coming from bassier earphones, though their slight warmth prevents them from coming off as sterile or analytical; they’re more akin to the articulate Grado GR10E than the more clinical Hifiman RE-600 in the low-end. For my personal tastes, I would prefer just slightly more low-end, most notably, the Prisms have an immediate lack of sub-bass, even among balanced armature earphones. While I used to believe that no armature earphone could reproduce sub-bass as well as a dynamic, a few have proved me wrong, the Campfire Audio Nova being a prime example. For Plussound’s asking price, I would expect a little more as the Prism has almost no sub-bass slam. And while their slight deep bass hump helps to imbue the sound with a little extra depth, the Prism produces a noticeably less visceral bass response than the 64Audio U3, Dunu DK-3001 and Nova. In all honesty, it probably won’t detract a lot from the listening experience for those who prefer balanced armature earphones, though those who are accustomed to dynamic drivers will find the Prism to be lacking that extra dimension. In return, the Prism is the most taught and has the best bass resolution of the bunch though buyers will ultimately have to consider their priorities and preferences.

Mids –

Despite the Prism’s lean low-end, I suspect their midrange will be the most polarising aspect to a lot of listeners. Midrange tuning resembles the Hifiman RE-600 quite a lot, they carry the same mid-forward presentation that is well balanced and linear throughout. And with that tuning comes transparency that makes the sound of the Prism very track dependent. That’s not to say that they aren’t versatile, but the Prism doesn’t flatter poorly mastered or encoded tracks like the more clarity orientated Dunu DK-3001 or even the 64Audio U3. Another interesting factor of the Prism’s midrange is their restraint. Where the vast majority of earphones around this price pursue that archetypical hi-fi sound that boosts clarity to achieve a revealing sound, the Prisms are rather quite mellow and they can sound almost veiled compared to other similarly priced earphones as a result. I wouldn’t call them an inherently veiled earphone in isolated listening, but they are susceptible to sounding a little closed off and sometimes nasal on poorly mastered tracks, something the RE-600 didn’t suffer from. For instance, the Prisms sounded natural and realistic when listening to David Bowie’s “Everyone Says Hi” but sounded hollow and veiled when listening to Hilltop Hood’s “I Love It”. This can be taken as both a negative and a positive because transparency is something a lot of manufacturers strive for but fail to achieve and Plussound have most definitely attained it. But as a result, the Prisms are more temperamental than most other earphones and buyer enjoyment will depend a lot on music tastes; they excel with Asian music, electronic and modern pop but lack aggression for rock and clarity for jazz.

But though I think the Prims tuning is mostly well done, their quality does leave me wanting compared to the immediate competition. Starting with the positives, vocals on well-mastered track such as Akdong Musician’s “Play” album have a really unique, sliky character and a dark background which grants mid notes with a quality of refinement. They are super clean, every instrument is intimate due to their mid-forward tuning though each note is surrounded by its own space that prevents the midrange from becoming even remotely congested or over-forward. By comparison, the substantially clearer and more spacious DK-3001 lacks the separation of the Prism, and this quality is the Prisms greatest asset in the face of the hyper-revealing U3 and the super dynamic Dunu. Resolution is also impressive, similar to the DK-3001 but failing to match the U3. Detailing is where the Prisms falter, neither foreground nor background detail retrieval is quite as good as the competition. Their more laid-back nature further exacerbates this issue as does their lesser clarity; they don’t retrieve details like the DK-3001 nor are they as revealing as the U3’s. The upside to this is that the Prisms are better suited towards long-term listening than most though they do miss some upper midrange bite which saps them of a lot of engagement.

Treble –

Luckily, the Prisms do a lot to redeem themselves in their treble performance, both in tuning and quality. Similar to the rest of their sound, treble is very neutral and linear but has fantastic extension. The Prism produces incredibly realistic and natural treble tones that quickly reveal how peaky a lot of other earphones are. Compared to the DK-3001, the Prism was immediately more natural and less splashy within their lower treble, where the DK-3001 gets a bit uneven. The U3’s are more revealing and possess considerably more treble attack, but the Prism separates better and will be a far better choice than either for those who are sensitive to treble. When listening to Radiohead’s “Creep”, a song that easily reveals any lower-treble faults, the Prism provided a very lifelike and accurate performance with minimal compromise on detail or clarity. Cymbals were textured and lacked any splashiness. The DK-3001 and U3 are both notably more forward within the lower treble, a common tuning technique that enhances treble detail presentation. That being said, neither was substantially more detailed; perhaps the DK-3001 was very slightly more detailed at the expense of sounding a little crunchier. Radiohead’s “No Surprises” revealed similar findings. All earphones did a great job resolving the fine treble detail within this track and also discriminating between each guitar strum, vocal effect and treble tone. As before, the Prisms had the best separation, the U3’s provided the clearest rendition of each instrument and the Dunu’s contained the most information though treble was slightly busy, slightly compromising separation during certain passages.

Of course, the Prism’s treble response isn’t perfect either, and while their extension is nothing short of impressive, the 4 driver Dunu’s and triple driver U3’s resolve slightly more within the very highest registers. Elton John’s “Rocketman” illuminated a small roll-off at the very top of the Prism’s frequency response that made high hats sound slightly truncated and thin on the Prism. By contrast, the U3 had more air to these notes while the Dunu had more texture and detail. That being said, when the track gets complex, the Prisms once again demonstrates that dark sense of space between notes and this quality is perhaps most important within the treble. It’s great to see that up top, their super clean and separated presentation is backed up by matching resolution and detail, providing a thoroughly compelling high-frequency performance that is just as rewarding as class leaders around this price, just more natural.

Verdict –

The Prism is surrounded by nothing but excellence and manufacturers need to do a lot these days to really stand out. Plussound have made a noble effort breaking into the iem market, their pricing demonstrating their confidence and experience within the field. And in person, the Prism is just as unique and exclusive as one would imagine, given its 3D printed housings, proprietary dual drivers and splendid custom cable all topped off with that charming handmade vibe. However, I can’t help but feel that the Prism is missing that last acoustic element that makes a $550 earphone sound $550. Mostly, I would attribute this to their midrange performance which is just a little too laid back and flat. I’m sure many will love the tuning on the Prisms but I think just as many will prefer the tuning offered by competitors.

The Prism isn’t a bad earphone at all but I suspect the Gamut with its extra midrange driver is really Plussound’s golden child. But that earphone is more expensive yet and the Prism is already slightly pricier than even the U3, Nova and DK-3001 ($549 vs $499), that’s B-stock Jupiter pricing! But beyond their sound, Plussound’s brilliant cable and 3D printed housings are immediately sturdier than competing models. Sure, the stainless steel Dunu is more rugged, but the Prism isolates far more while being more ergonomic in every way. The Prism will captivate listeners looking for a non-fatiguing, comfortable and natural sounding earphone; because at the end of the day, comfort and individual preferences are just as important as the earphone’s technical ability.

Verdict – 7.5/10, While the midrange leaves me wanting, the Prism is ultimately a transparent and natural sounding earphone with fabulous resolution and separation. Top that off with superb comfort and isolation and the Prism makes for a nicely rounded product. The Prism is a good earphone augmented by a great cable and I look forward to seeing more earphones from Plussound in the future.

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