General Information


PENON SERIAL Triple Dynamic Driver 2Pin 0.78mm Audiophile In-Ear Monitors


Medical grade resin cavity, light and beautiful, comfortable to wear, no strange feeling in contact with the skin.
Semi-transparent black shell, the panel is made of stabilized wood red, blue, and green 3 colors mixed
Made by hand, the earphone shell is solid and more durable.
6mm pu diaphragm for high frequency
8mm titanium-plated for middle frequency
10mm biological diaphragm for low frequency
Resin shell, stabilized wood panels
3-way crossover, 3 tubes
Stainless steel nozzle

Brand Penon
Model: Serial
Driver: 3 Dynamic Driver
Impedance: 18 ohm
Sensitivity: 103dB
Frequency response: 20-20kHz
Connector: 2Pin 0.78mm
Plug: 3.5mm audio, 2.5mm balanced, 4.4mm balanced
Cable: 8 shares OCC & silver-plated Mixed Braided
Cable length: 1.2M

Latest reviews


Headphoneus Supremus
Very Engaging and highly satisfying
Pros: Excellent texture, fantastic layered bass, some of the most melodious and smooth vocals.
Cons: It trades musicality for details, doesn't have the best treble region.

From being one of the prolific online seller in the world to a cable then IEM brand, Penon has ventured deep into the Audiophile market. They have been making good amount of IEMs for various type of consumers. They have single DD to multi BA and multi hybrid IEMs under their belt and the Penon Serial is their latest addition. It's an unique kind of IEM with 3 dynamic drivers in a 3 way crossover. The tech is not exactly new in the market but the implementation of the UM 3DT wasn't exactly excellent. Penon has a different strategy here. They have a 10mm bio DD for bass, 8mm titanium plated driver for mids and 6mm PU DD for highs, interesting combination of drivers I must admit.

Penon has been making excellent sounding IEMs and I am expecting a pleasing experience with the Serial. Priced at $299 it comes in only black color and goes head-on against the CFA Satsuma, UM3DT and many other DD based IEMs.

Get one from here:



Serial ships with the usual Penon style box and has 6 pair of tips.



Serial has a unique kind of shell. The body is mostly made out of resin for better stability and durability but the back plate has pieces of stabilized wood on it with layers of resin on it. As usual the shell the solid to the hand and feels light weight. There is a single vent on the side of the shell. The metal nozzle looks good but isn't really premium feeling. What's odd is that even with a resin body the IEM doesn't have a more ergonomically designed wing. This should have been better but thanks to light weight and deeper insertion serial is fairly comfortable.




Penon Serial ships with an 8 core OCC + SPC cable. Its Not the most premium cable in the market but it still looks good and somewhat compliments the IEM aesthetically. A silver coated cable could have made this pairing more appealing. It's an supple and soft cable without much memory problem. It barely has any microphonics to worry about. What I really like is the lack of cable guides. There are some stress relieving at the jack end but doesn't have much protection anywhere else. The cable splitter looks nice while chin slider is a bit too big. Sound wise this cable is not bad, upgrading to something like Effect Audio Grandioso or similarly priced Silver cable will make sense, or else it does the job.



Serial just like any other DD based IEM doesn't really care a lot about the source but it enjoy power without any guilt. The worst performance is with mobile devices but that too is above average while driving it from something like Fiio KA3 and Qudelix 5k brings out the best of it with better details and transparency.


It has 3 DD in a 3 way cross which delivers one of the most cohesive sound in any price range. Cohesive has been a great USP for Penon. Their ORB too was excellent in this regard. This takes it even further. It has a reasonably balanced sound with a Slightly W shaped feel. The mid range is not drowned while the lower end and lower treble region are a bit more forward.

There is little to no coloration while having one of the most uniform notes presentation. I love this. No note feels out of place or gives an odd vibe.

I am using Tri-TK2 and stock tips for this review while changing cables.



Serial is very pleasant sounding IEM with exceptional lower end abilities. I can write the conclusion here. You read it right, you can stop reading here and grab the Serial for it's lower end quality. There is no other IEM in the market which can deliver an lower end like this under $500. If you are a bass lover, want to enjoy the goodness of lower end without any guilt, this IEM will do wonders. The sub-bass extension is excellent, very deep, rumbly and has the eargasmic air moving quality. The whole lower end feels meaty and full which gives it the cohesive but this does lack the speed one might look for at times. The layering and definition of notes are exceptionally good in the lower region.

Now the question arises, Is it an IEM for bass heads? Yes and no. Yes because it's layered and defining prowess with weighted notes make it a delight to use but then it doesn't have the area or volume of a bass-head IEM like Satsuma or ISN D10. Serial's lower end has tunnel like feeling while others are flat.


Loved the lower end. But there is more to it. Bass is excellent, so are the vocals and mid range instruments. It's not the most detailed mid range by some margin but the rounded notes with thicker fuller and weighty nature gives it a calming and soothing signature. If an Audiophile who wants details and finishing definition, let me tell you, this might not be for you. It has very good edge definition with excellent texture on both vocals and instruments. Both male and female vocals have some of most pleasing tonality and timber with a throaty feel. Female vocals don't feel unnaturally thick, that's the beauty.

Another remarkable feature is it's reverb. This reverb gives the Serial an captivating quality. It's simply feels hypnotizing at times. It simply submersive.

Instruments have good details but the resolution and level of transparency is not high. Upper mids have good energy and details but the instruments before and after the vocals can be slightly mushy.


What? Are you still here? Are you not convinced? This is the IEM for you!! Go get it.

If you still are reading on, either you are just curious or like to do some critical listening at times, if you do, this IEM might not be for you. The treble region is not bad, it has good extension and reasonable relevance but doesn't have a lively feeling to it. The spark isn't good. It's doesn't have any offensive feel to it, which is a positive. Layering and separation are not class leading. Micro details are not exactly present in the treble region.. This has two conclusions. 1. It's a bass lover's delight, let's you enjoy without interruption. 2. It's not for those looking for treble details.


Serial has good stage expansion, it's not very big though. Stage height is good near the head but gets better at the upper mid lower treble region which are placed out of the head. The Z-Axis is very good for the price but the X-axis could have been better.

Nearly 80% of the lower end notes are placed inside the head. Vocals have reasonable presence out of the head while 95% treble notes are placed out of the head. Cue placing abilities of this IEM is very good too. It's dynamically adjusting stage gives it very good sonicality.



Hmm, waited for the conclusion? Aight, let me give it to you in simpler words.

Serial is for a bass lover who wants excellent texture, layered notes, excellent sub-bass with meaty mid bass. It does not unload a huge punch or volume but the experience is satisfying. The slower decay helps a lot too. Serial is suited for enjoying the music, its melodious and calm. If you want a lot of details, attack and traction, you can look at other options like Audiosense T800 and even the Shozy B2 makes more sense.

This is it guys, enjoy!!


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Excellent review! It's amazing how popular IEM's have become over the past decade. These are also really nice looking.
Made in China?
Great analyses, succinct and insightful. Listening to them now off my desktop and they sounds great.


1000+ Head-Fier
Evolution of Musicality
Pros: Significantly matured take on Penon's house sound, extremely balanced and versatile tuning
Excellent dynamics
Delicious sub-bass with excellent tactility/physicality
Rich lower mids that do not predominate over other frequencies
Ideal upper mids elevation, good energy without any fatigue
Well-balanced treble response that hews closely to neutrality
Excellent soundstage height
Superb layering
Very precise imaging
Very good timbre and coherence
Great fit and comfort
Excellent stock cable
Cons: Resolution doesn't quite match BA/EST implementations
Not the absolute largest soundstage out there
Anti-sibilance scoop mutes some instrumental harmonics
Minor channel matching issues

Introduction: The past few years have seen a renaissance in dynamic-driver based IEMs, and a few of the more adventurous manufacturers have begun to branch out into triple-dynamic earphones (a category which historically has been represented by only a few implementations, most of which shall we say left a fair bit to be desired). I really the Unique Melody 3DT last year and it remains one of my favorite IEMs, although the upper mids and lower treble are tuned a bit aggressively on that model. So I was extremely excited when I heard that Penon Audio was developing their own triple dynamic, especially since Penon is one of the few manufacturers which reliably employ a more restrained and neutral (to my ear) pinna gain than is often the case with ChiFi earphones.

Due to life circumstances I was taking a break from the hobby when the Penon Serial was finally released, but although I am late to the party I can nevertheless now affirm that the Serial does not in any way disappoint, and is one of the most compelling options out there for those who love the sound of dynamic drivers but are hungering for more technical capability than most single dynamics can provide.

I would like to thank Penon Audio for providing me with a sample of the Serial in exchange for my honest review. You can purchase a copy for yourself here at an MSRP of $299.

The specifications are as follows:
  • Driver: 3 Dynamic Drivers
  • Impedance: 18 ohm
  • Sensitivity: 103dB
  • Frequency response: 20-20kHz
  • Connector: 2Pin 0.78mm
  • Cable: 8 shares OCC & silver-plated Mixed Braided

Packaging & Accessories: The packaging comes to us in the now-familiar Penon Audio classic yellow slip-cover — a bit spartan, not exactly signifying the outstanding audio quality found within, but of course perfectly serviceable. Within the cardboard box itself is a blue faux-leather zippered carry case — similar to that which for example graced the Globe, although it seems to me that the quality has been improved (for example, the dye seems richer this time). There is also a leather pouch for storing the included Penon CS819 cable, which is a nice touch — especially for those given to cable rolling.


The CS819 cable (a mixed OCC and silver-plated braid) is itself quite good as an aftermarket cable, and the inclusion of a $49 cable with a $299 IEM is certainly to be commended. The other accessories are quite satisfactory as well — the normal blue and green sets of silicone tips (as usual, I prefer the green) often included with Penon IEMs, as well as a set of foam tips, a cleaning brush, and a cable clip.

Build & Comfort: Coming from the gargantuanly-sized and fairly heavy UM 3DT, I was amazed at the normal size of the shells of the Penon Serial and even more so at their extremely light weight. The resin is shaped in a fairly rounded manner which should work for most ear anatomies, eschewing the semi-custom shape which can be much more hit-or-miss. The faceplates of the Serial follow the now-popular trend of using a stabilized wood panel, multicolored but still fairly restrained in appearance especially being yoked to the black resin shell.


Isolation is very good despite the presence of venting, especially since the shells fill my medium-small ear cavities quite well. I experienced no driver flex or vacuum effect. The shells are quite comfortable even over longer listening sessions, although the protrusion of the shells prevent the Serial from being a good candidate for side-sleeping.


As far as the driver configuration goes, the Serial actually differs a bit from the approach taken by Unique Melody with their 3DT. Whereas the latter employed two 7mm drivers to handle the bass in tandem and a single 10mm driver for the mids and highs, Penon has opted to deploy a 10mm biological driver for the lows, an 8mm titanium driver for the mids, and a 6mm PU driver for the highs. There is a three-way physical crossover to separate the sound frequencies.

I will note that my copy had some slight channel matching issues, nothing horrible, but others have experienced some issues as well so it’s something worth mentioning. However Penon customer service is always excellent at resolving issues should they arise.


Signature: The Serial — like most Penon IEMs — has a signature which is difficult to immediately pigeonhole. What is readily apparent from the first moment, however, is that the Serial is easily the most mature tuning I have heard from Penon yet. It's definitely not neutral, it has the characteristic full-bodied musical midrange of Penon's house sound, but it is no longer so bold and perhaps even ostentatious as on some other models; rather, it is tastefully restrained and extremely well-balanced with the other tonal regions. The bass is somewhat emphasized, although once again in a very tasteful way, and certainly emphasizes quality over quantity. Treble, on the other hand, is fairly neutral aside from a mild-to-moderate anti-sibilance scoop. All in all I think the overall presentation is close to a bass-boosted neutral (although again with a tasteful addition of some of Penon Audio’s signature lower mids warmth), but is quite a bit more dynamic sounding than is typical for this signature.

One thing to note about the Serial is that it is extremely tip-sensitive; I cannot remember the last time I rolled as many tips for an IEM as I did while writing this review. On the one hand this offers probably one of the most customizable sounds out there without involving some sort of tuning mechanism; on the other hand, one can perhaps even get a bit overwhelmed by the number of choices if your tip collection is large!


Bass: The sub-bass here is extremely delicious, with beyond excellent physicality, and the bass is biased somewhat toward this subregion. The mid-bass on the other hand is no slouch by any stretch of the imagination, exhibiting stupendous control and outstanding texture. There is plenty of tightness and agility throughout the entirety low end, enabling the not-insubstantial elevation to nonetheless remain in good balance with the other tonal regions. Being powered by a DD the decay is slightly on the slow side — though only enough to impart a moderate sense of atmosphere to the sonic presentation, and it always maintains good cleanliness. Note weight is somewhat thicker than average, but the notes themselves have a very good definition to them. All in all, it’s been a long time since I was this pleased with an IEM’s bass response.

Mids: The midrange is the bread and butter of the Penon house sound, and although some might consider the Serial to be something of a departure from this house sound, I actually consider it to be an evolution of it instead. The familiar warmth and fullness are still here, yet rather than the euphonic exuberance of previous models, we instead receive an organic bridge between the bass and treble, one which hints enticingly at lushness but always remains tempered by maturity and a sense of faithfulness to the recording’s natural properties.

The lower mids are, to me, the star of the show, and have a wonderful warmth, richness and texture that nevertheless does not predominate over the rest of the tonal regions. Pianos sound absolutely outstanding, with just the right note weight for my preferences. Cellos likewise sound very full and rich, although depending on the mix sometimes they can be just a bit too thick. Male vocals are not as euphonic as on models such as the Globe, opting instead for an extremely natural and tonally correct presentation.

But of course, great lower mids on a Penon IEM are not surprising. What I was pleasantly surprised by, however, was the upper mids which to me have now found their sweet spot, being more prominent than on other Penon models but still well back from the (to my ear) exaggerated and shouty Harman target. Female vocals and strings now have their proper energy and presence, but without any shout or fatigue whatsoever; sibilance, likewise, was nowhere to be found.

Treble: The treble region displays a similar evolution to the Penon house sound: whereas some of their prior models have leaned somewhat dark, here Penon has opted for what is (to my ear) fairly dead-on neutrality. This does come with several caveats, however. The first is that proper burn-in is a necessity, as for many people initial out-of-box experience can be a bit underwhelming in the treble region. The second is that even after burn-in, there does remain an anti-sibilance scoop in the lower treble that somewhat mutes certain instrumental harmonics. It is a much less aggressive scoop than on many other IEMs (the UM 3DT comes to mind here), but it is there and buyers should be aware of it. Although this is probably my favorite Penon IEM for treble that I’ve yet heard, nevertheless it’s still not an IEM for trebleheads. But it does strike an excellent balance in that it retains a respectable amount of air and sparkle while accomplishing the task of staying thoroughly fatigue-free.


Soundstage & Technicalities: Although the Serial is a hybrid, it is still a triple-dynamic hybrid and so one expects the technicalities to improve over a single-DD while still falling somewhat short of BA-level performance. And in general, I think this holds true, especially in resolution and detail which, while respectable, are not earth-shattering. But there are some areas where the Serial manages to exceed these expectations: for example, the soundstage has good width (though certainly it is far from the widest IEM I have ever heard) and it actually has good depth as well, but what is really remarkable is how incredibly tall it is. This advantage in height in turn allows the layering to be close to the best I have yet heard in this price range, even despite the fact that the warmth of the midrange prevents there from being a lot of air between the instruments. Add to this the outstanding and nearly-holographic imaging performance, and the result is a level of technical performance with which I am extremely satisfied. Yes, the timbre and coherence of the Serial do not quite reach the levels of the best implemented single-DDs, yet especially after burn-in (the midrange DD in particular needs some break-in before it gets into good sync with the other drivers) they get fairly close and much closer than almost any traditional hybrid.

Select Comparisons:
vs. Unique Melody 3DT: This is the fairest comparison I can think of, since they are both triple-dynamic earphones selling around the $300 price point. The Serial has noticeably smaller, lighter, and more comfortable shells, and there is no driver flex or vacuum effect unlike the 3DT — although the tradeoff is that the 3DT isolates better. The 3DT has a somewhat colder midrange in general, and it has more aggressive and more peaky upper mids and lower treble — although these do give the 3DT a greater sense of openness, clarity, and perceived resolution. Technicalities in general are close, and so other than fit issues (which are far from insignificant!) the decision comes down ultimately to tuning preferences, with the Serial being more musical and relaxed and the 3DT more energetic and open.

Conclusion: The goal of the triple-dynamic driver setup is clear: to attain to at least a significant measure of the technical capabilities of hybrids, without their inherent compromises in timbre and coherence. I think it is beyond clear that Penon has achieved this goal, and done so at quite an attractive price point. The tuning is, in my opinion, a significant step forward for Penon: it is now much more balanced and extremely versatile, while still retaining the fundamental musical appeal of the Penon house sound. The Serial has my complete recommendation.

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Had these and loved them. Sold them for quick cash and regretted it ever since. Gonna buy them again some day. Great review.
Scuba Devils
Scuba Devils
Great review and I also sold and regret! I will definitely buy again.
Thanks for your time to write this review! really considering buying a set:)!:ksc75smile:


Headphoneus Supremus
Penon Serial. A unique 3 dynamic earphone.
Pros: Utilizing 3 different sizes and types of dynamics with each driver specializing in the sound region it is taxed with. 3 way crossover design in a semi custom all resin shell with vent out back. .78mm 2 pin design. A diffused wide stage with excellent detail, more neutral in tuning with sub bass emphasis. Very good clarity and well balanced. Non fatiguing treble, clean well imaged mids with a proper bass emphasis. Incorporating one of the best value Penon cables the CS819.
Cons: neutral lower mids, male vocals are not the best on the serial.
Penon Serial

Triple dynamics earphones are rare in the industry and even more rare if you think about how many hybrids, dynamics, tribrids and all BA earphones are available vs the triple dynamic. The idea behind using 3 dynamics is to focus each dynamic driver on one aspect of the sound tuning. Penon has taken that idea one step further and incorporated 3 different types and sizes of dynamics with each driver specializing what it does for the sound bands it is taxed with.

The treble dynamic is a smaller more agile 6mm Pu diaphragm dedicated for the highs, 8mm titanium plated dynamic known for its detail and imaging properties for the mids, 10mm bio dynamic specialized for its bass properties. It is encased in an all resin poured housing with a vent out back utilizing a 3 way crossover system finished off in a 2pin .78mm connector design. The size of the housing is a compact medium in physical size for an all resin design, which should fit a majority of ear shapes with comfort giving decent passive isolation.

It has been a while since Penon has done a pure dynamic offering and a first for a triple dynamic design. For fans of dynamic earphones these should catch your interest for several reasons. Firstly this particular design is even more rare as it is using 3 different sizes and 3 types of different dynamics. Could be the first in the industry actually. Then the other aspect is that it is designed and tuned by Penon which if you go off of their history of in ears, you're getting a highly refined high quality product. All their designs and tunings are done in house. Penon does not produce numerous models of inears under the Penon brand, again the only other dynamic earphone offering under the Penon brand was their limited edition Penon Fan earphones.

Standardly disclaimers: I would like to thank Penon audio for the review sample. An early production sample was provided for my take on them. I have no affiliation with Penon and will relay how I hear the Serial to you, the enthusiast. If you must own the serial you can buy you a set here. They have been burned in for a week straight and are now ready for evaluation. Sources used are as follows. IBasso DX300Max, Fiio M15, Shanling M6 pro, M5s, M3s, Fiio K2 2021, KA3, IBasso PB3, IFI Black Label for amping.

What you get.

Serial comes with Penon’s Blue rectangular zip up case. Hearty and roomy this case has been the mainstay of all Penon products. Why change something that works? It has enough room in the case for the Serial, the cable and your tips. 2 sets of silicones, a medium pair of foams, and a very nicely matched Penon CS819 cable in any termination you want when ordering. Highly recommended, balanced termination using a balanced source as the Serial loves a bit of power.

The CS819 is Penons basic 8 core hybrid cable. Half the cores are silver plated OCC and the other half OCC, 8 cores 19 shares per core. The cable pairs very nicely with the serial sound presentation as it is mostly higher end copper in sound properties which adds a bit more body enhancing a natural tonality with a solid bass impact to the Serial sound presentation. The retail value on the CS819 itself is $49 and is worth every bit of that money. These cables are without a doubt one of Penon’s best value cables. Not to mention how good it matches with the Serial. The cables can be purchased here.

While a lot of folks might overlook the included cable with their earphones. I will tell you Penon has improved their included cable pairings. You didn’t get this level of cable with their previous earphone offerings especially at the retail price of the Serial. Let me put it this way. The Globe being sold for the same price has an ok included SPC cable. But the ok cable is not the CS819. The CS819 was included as a sound design aspect for the Serial. The copper element of the cable is a good clue in the types of cables you should try to match up with the Serial if you are the type that never lets good enough alone. Of course using higher end cables on the Serial yields even better sound. Silver based for more detail, more treble and stage expansion. Copper based for more fullness, greater note weight and the best bass performance. Or how about a bit of both. Shown with upgraded Penon Mix

The sound
Serial leans a bit more toward a reference type neutral diffused harmonish tuning. It is a mildly V shaped in signature but very tastefully done to add enough emphasis leaning toward sub bass and the mid trebles. This is the type of tuning what you would hear more commonly for higher end headphones. Given the technology and drivers involved. Why not go for a wide expansive neutralish mild v tuning. Its tonal qualities are more neutral in its mids presentation with a sub bass boost is how I would describe the sound profile. While the Serial is not a ruler flat by the numbers neutral tuning. I doubt Penon will ever do a tuning like that, however the Serial is as close to a neutral tuning as you're going to hear from the group. This is a slight departure from their BA offerings as their BA/hybrid offerings all have some type of mids coloration that is the hallmark of the Penon sound. Rated at 18 ohms with a 103db of sensitivity. The Serial sounds great out of anything, easy to drive but due to the dynamic nature of the design, amping the serial has its advantages for increased dynamic range, expansion and detail. Serial likes a bit of current and power to achieve optimal sound.

Is handled via 6mm pu diaphragm. Micro dynamics have their inherent strengths on the high notes. Just based on my own experience with micro dynamics. Companies like JVC, NuForce, Final and Sony has utilized the micro dynamics to full effect in the past so it was good to see Penon using such a driver. The idea of utilizing a dedicated dynamic treble driver is that it works like a tweeter driver for all the notes past a certain high frequency. What you get is a clean, clear detailed separation of the high notes. Just my opinion but I wish more manufacturers would use dynamics for highs. The advantages of using a dynamic is that you get a more natural tonal and better blended treble character when using a dynamic.

Its emphasis has a good balance of presence and detail. Imaging and transient qualities of the Serial for the treble is very good. As a side note I do recommend a burn in for the Serial as the trebles on open listen was a touch subdued, the treble dynamic seems to wake up and expand with better qualities with burn in. Also as a side effect, expanding the scope of the stage presentation. What's very inherent with the Serial treble is that it blends with the rest of the sound like it was coming from a single driver. Using a 3 crossover technique to achieve that coherency the treble blends a natural smooth non fatiguing take on treble within the sound presentation. True to the Penon house sound, the treble presentation here does not stand on its own, but plays more of a supporting role for the mids and bass. As such you will not have to worry about treble grain or undue treble spikes for a Penon tuned IEM. Treble design has the most emphasis for the mid trebles with a dedicated deemphasis for upper trebles. I wouldn’t say the treble is overly rolled off, it is more deemphasized for the upper trebles to not cause a tonal shift or fatigue, letting the natural mids sound qualities be the star of the show for the Serial sound presentation.

Depending on the tips and cables you use. Trebles become airy and better extended but for the most part its detail level is done very well for the given price level. I own the IER-Z1R which also uses a dynamic for trebles and those are my bar for using dynamics for trebles. And while the Serials treble presentation is not as refined sounding, it's got a satisfactory quality and more importantly blends well with the overall sound presentation. Treble tonal qualities, its emphasis is leaning toward a smoother presentation, agile, crisp with good extension and detail are its strengths. Excellent treble dynamic chosen by Penon.

Mids of the Serial is utilized by a titanium coated 8mm dynamic. Titanium plated dynamics are known for its clarity and detail qualities for the mids. Here we get that with the Serial. The strengths of this particular driver comes through in this design and I would put the mids detail as above average for dynamic earphones. The tuning is a bit of a departure for Penons BA design. This is the area I feel has the most neutrality in emphasis and tonal qualities. Folks looking for a more meatier sounding earphone might be a bit disappointed with what Penon has done for the Serial. The mids are detailed, clean and have about 8 dbs of pinna gain for upper mids presence.

It does female vocals better than male vocals since the lower mids is where there is less emphasis. Its mids are more accurately presented vs being overly exaggerated or having too much of anything. It is more closer to a monitor type neutrality vs being too dimensional or thick in note weight. Its timbre while accurate comes off a touch dry with a quicker sustain. The tightness of the sound is clearly evident from the upper mids to the lower mids. I can tell the titanium dynamic here is a bit stiff and perhaps does not move air as well as the bio dynamic used for the bass. Serials clean imaging, its wide sound presentation along with that detail is the strength of the Serial mids dynamic. As mentioned above female vocal renditions hit them high notes and these are so proper for female vocals.

Instrument separation and imaging is also a stand out for the mids design. The sound presentation is uniquely wide in earphone presentation. Wider than tall or deep. Sound has more depth than height but the width of the stage on the Serail adds to that neutrality reference headphone like presentation. Due to how wide the serial sounds you actually get a better separation in the presentation for instruments that play on that field. Its black space with that wider diffused stage provides a nice broad canvas for you to pick out details. Folks that like to listen to big bands or live performances will love how the serial sounds for such recordings.

A 10mm bio dynamic here is a bass specialist dynamic that was used on previous earphones like Yanyin, Vsonic, and Sony products. The strength of the Bio dynamic is its ability to have a roundness in bass tonality with an ability to dig deep without much struggle. It is the bass dynamic which is the biggest driver being used for the Serail and I have yet to hear a bio dynamic fail at bass. The emphasis for the bass presentation is more sub bass than mid bass. It has a goldilocks of bass emphasis at roughly 8dbs of sub bass shelf. It has the right impact and anything that hits them sub bass notes the Serial will come out to play.

The transition from the mids to the bass end is seamless, smooth in transition and is once again very coherent with the rest of the sound design. Mid bass speed is about average but is fast enough to keep up with busy metal tracks. Beefy enough to sound proper with EDM and bass genres. Its deeply textured sub bass rumble is excellent. These are not basshead in levels but satisfactory for bass to sound complete with a proper sub bass extension and rumble. As a design choice you can have a neutral lower mid emphasis but a neutral bass emphasis? I don’t think so. Never heard a Penon made Iem with neutral bass. I doubt they will ever tune an earphone with neutral bass. Bass is very gifted emitting a high quality bass definition to impact ratio. I have to give credit to Penon in trying out various types of dynamics to achieve better results for its bass presentation and the Bio dynamic has proven to be one of the best for earphone designs. Serial has a proper bass and being true to the Penon sound. You get a satisfactory bass end to enhance your music. The quality bass here is not only a strong suit but the emphasis is perfectly suited for just about all types of music you listen to.

In the end
The Serial is yet another fine example of Penons tuning prowess and their ability to present one outstanding earphone after another. They went for a slightly different tuning using a different unique driver design this time. The Penon fan was a precursor to what the Serial is. These are unique in many ways using 3 different sizes with 3 different types of dynamics all 3 with excellent ability to portray an accurate sound taxed for their sound output. The coverage from the lowest of bass notes to the highest airy treble notes are easily portrayed with the 3 dynamics throwing out their absolute ability. I have posted on previous Penon earphone reviews that I have yet to see Penon do a neutral tuning.

The Serial my friends is the closest it will get to a neutrally tuned Penon earphone it will get from the group but one with some outstanding addictive technical qualities. Their wide earphone stage presentation mimics a headphone reference stage and in doing so the Serial portrays a different type of musicality. True to the Penon house sound, the Serail is all about the mids and its rich bass presentation with a clean smooth detailed treble. Its dynamic sound tuning is every bit as engaging as anything they have made in the past. It is good to see Penon trying out a different variation of their house tuning philosophy and it seems everything they make reaches a certain level of sophistication and ability. The Serial is the most unique out of their line up and is a great addition to the Penon collection. As always, thanks for taking the time to read.

Because you asked. Some comparisons.

Penon has a hybrid that is priced the same as the Serial. Yes we are talking about the Globe.
Vs the Globe. Globe uses a full range Sonion BA for mids and a Knowles BA for trebles + a 10mm dynamic for bass. If there is a classic hybrid that is a fine example of the Penon sound. It is the Globes. You can read some reviews of the Globe here. Against the Serial. These two have similarities in treble and upper mids emphasis but from lower mids to bass is where they are different. The Globes have more lower mids emphasis therefore it has a greater note weight and fullness to its tuning. It is more efficient vs the Serial but volume matched the differences are evident. Dynamic timbre vs BA timbre there is a difference there. Though BA timbre some may look as a negative but if you haven’t heard a Sonion BA do mids proper then you need to get yourself an Orb or Globe and hear a Sonion BA do mids proper. Serial has more of a natural sound signature but has more of a neutral lower mids emphasis so music sounds more accurate and not as forward sounding. Presentations are different. While the Globes have a bit more in the way of bass emphasis and a touch more warmth to its tonality, I have to give the bio dynamic bass of the Serail the edge when it comes to bass. Both are very good bass ends but the Serial bass has a slight edge in detail and quality over the Globes bass. Both have similar treble emphasis with the serial again emitting a touch more naturalness and smoothness for its treble end. I would also give a slight edge in stage expansion to the Serial. Globe however is very close in stage here as well. Both are wide with the Globes having a bit more in the way of height of stage.

Against the ISN SCB2.

You want to talk about stark differences in presentations. The SCB2 is as close to a western tuned IEM made by a Chinese manufacturer as it gets. Its tonality is warm with a bit of darkness to its tone due to the big bold lower mids and mid bass it has in comparison to both the Globe and the Serial. The SCB2 is a much more colored earphone vs the Serial. More in the way of mid bass so for folks that love them some bold forward bass the SCB2 is what that is. It's got a unique tall and deep sound to its presentation and due to the emphasized lower mids and bass end the SCB2 is uniquely suited for bass genres and more weighty music in general and one of the better dynamics for male vocals. Its treble has slightly less emphasis vs its bold bass end but has a proper extension and treble presence for its overall tuning. These are the opposites of the Serial presentation with more of a neutral level of lower mids so you couldn’t get two more completely different presentations than these two. Serial definitely wins the stage here width wise but again that unique tall full sound signature of the SCB2 has its own musical sound that some will like more over the Serials more neutralish presentation. You like your sound bold forward with a rich tone that is what the SCB2 is all about. The Serial does not sound as compact with a wider more diffused sound presentation. Its bio dynamic here is more focused in the sub bass region the SCB2 more mid bass but has enough sub bass grunt to make it sound complete.

So going from the least colored sound tuning to the most
Serial > Globe > SCB2
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@listener26 all 3 you mentioned would be an upgrade to the H40. Try out the Aladdin see how you like that one since it is the cheaper of the 3 earphones.
@Dsnuts thanks bro, my h40 was one of the best I've ever bought and has prevented me from buying anything else for 2 years. I hope i get another good buy from this 3.
Love the review! Could you make a comparison between these and the ISN H50? Not sure which one I should pick. I'm a basshead, but clarity in the mids and highs are also quite important for me since I game quite a lot



100+ Head-Fier
I wonder how the Serial compares to the UM 3DT. I own the 3DT and I really like it. Especially after adding the Tanchjim filters.