Penon Serial – Serious player!

If you're looking for a reference IEM packing a well extended powerful and fast bass, an articulate midrange and an engaging treble both with accurate tone then at the asking price it's hard to find a better proposition than the Serial. 

Serial addresses the demanding audiophiles on a budget and it's quite refreshing in a bullish market in the upper tiers. On top of this Serial will scale superbly with more power and an affordable desktop amp is a great option to enjoy all it can offer.  .


  • Deep rumbling physical sub bass
  • Powerful and fast bass with snappy attack and clean decay
  • Articulate and engaging midrange with accurate tone
  • Engaging well extended treble with excellent note weight and tone
  • Stunning price to performance ratio
  • Scales with more powerful amplification


  • Shells protrude, can’t use lying on the side if that’s in your requirements

Product Page :
Price : 299$

Fit, Build & Isolation

The Penon Serial features a black medical grade resin material shell with very nice and colorful faceplate (but which is hard to render properly in picture). The Shell is smaller than I expected for a triple dynamic. The shell must be quite crowded given the resonnable footprint of the Serial. As with some other Penon IEM, the heft is contained by a deeper shell which means it protrudes a bit but keeps size very reasonable. Like the Orb and Globe, you can forget sleeping with it lying on the side. There is a color coded vent with filter for bass.

Like previous IEMs in that range (Orb, Globe) is very lightweight. This is common to the lineup, isolation is average, but the shells are so light I am not too surprised. This shouldn’t be an issue in real world condition for most with music playing except for noisier environment if you’re a low volume listener like me. 

Like its siblings Orb and Globe, Serial is very comfortable IEM to wear with an average depth insertion and very lightweight it’s quickly forgotten and disappears in the ear.

The Serial thankfully features a standard 2 pin 0.78 socket and comes with CS819 which is Penon entry 8 core hybrid cable (copper, silver) with a decent 8 cores 19 shares per core I asked for a 4.4 cable you can choose termination when ordering. The cable is supple and with good ergonomics.


Like most people I know I have enjoyed Penon as an online shop, a trusted distributor of many brands I love like Dunu, Tansio Mirai or ISN to name a few. Penon started building IEMs (the BS1 earbud in 2017) and great value for money cables (like OS849).

In 2019 they launched their first IEM the Sphere and it was a success. Lately they have been on the roll with many highly praised products : the Globe, the Orb and higher up the lineup the Volt and latest flagship Legend (which I’ll review next) as well as cables such as the OSG cable and the flagship cable Totem. Following up on two excellent releases, Serial must live up to the Orb and Globe SQ and offer some degree of complimentary tuning.

The Serial is at the start of a trend of multi dynamic designs that have recently come up on the market. Serial features no less than 3 dynamic drivers : a 10mm biocellulose for bass, 8mm titanium cotaed for mids, 6mm PU driver for treble with a three way crossover design.

So how does the Serial take advantage of triple dynamic DDs?
How does it fit in the Penon lineup?

Let’s check it out!


I expected the Serial to have somewhat of a huge bass presence and a fun upper end with smooth midrange, somewhat of a variation of sorts on the direction Orb and Globe took which is not uncommon with the price tier.

Penon chose to go in a different direction : yes, Serial does features impressive bass power but with a lot of discipline and more of a powerful reference bass with deep subs than a fun, mid bass tilted tuning. Yes, Serial does exhibit their now well established midrange tuning knowledge but it’s an interesting more balanced mids than I have growned used to. No, treble wise Penon chose to go lighter on lower treble excitement in favor of a more refined upper end with more presence so overall a more balanced presentation. You can see the trend here, Serial is fun for sure but serious on its fundamentals and tuning. The stage is elliptical with excellent width and height, with average depth and imaging is precise.

Note that I mainly ran Serial with the excellent portable iFi Audio Go Blu but as we’ll see the Serial scales very very well with power and both FiiO M17 and Shanling M9 as well as my Pro iCAN Signature amp did show that all of Serial base quality will scale up nicely with power. An interesting option for audiophile on a budget is either get a portable or affordable desktop amp like my Zen CAN and enjoy this.

Anyway, a very interesting twist in terms of tuning and positioning in the lineup, I like where this is going…

Let’s dive a bit deeper!


The Serial features strong foundations in the bass : it’s a deep bass with subs which rumble with impressive power. My usual Aphex Twin “Ageispolis” test track provided thunderous physical rumble and the Serial managed to keep the bass in check so that the rest of the track is both deeply seated and articulate with the atmospheric sounds this tracks contains.

Mid bass control is flawless and speed is quite impressive this dynamic is fast especially when fed good power. Note attack is snappy and punchy, this is a bass that kicks hard with clean and fast recovery as well. Marian Hill “Differently” the quick synth bass notes start and stop on a whim which is a good test. The Serial manages to keep up with the fast drum and clap and the Serial deals very well with everything going on at once in an articulate manner.

Given its strengths, the Serial features an impressive amount of detail in the bass conveying a lot of nuances, bass line is very articulate, percussions subtle variations are perceived an textures are rich with nuances.

Serial bass is serious! You won’t find this kind of technicalities bass wise in that price range, period. Heck not even most of next tier can’t compete. Serial comes to play with much higher priced IEMs there, I am thinking Dunu Zen for example. This is good news for audiophiles on a budget that want bass that don’t compromise in speed, power, texture and extension. Color me impressed.


The Serial mids are not as full bodied as the usual Penon but more transparent and clear as well as more articulate with better separation, following in Globe footstep but taking this further. Instruments as well as vocals sound spot on on a reference source, and take on any coloration the source will give them so a bit warmer natural with my Go Blu and the M9 and more linear and reference with the M17.

The lower mids have good presence, it’s not thin mids but it’s a balanced presentation rather than a full bodied one like the Orb. The serial is more open sounding than the Globe that already was more open than the Orb. Instrument separation is excellent and the imaging is precise making for a very articulate midrange.

The upper midrange strike a very nice balance, there is excellent bite to both brass and woods but upper mids are safe – my usual Whiplash test passed. There is clearly a bias towards accuracy if you own an accurate source that’s what you’ll get with the Serial. You don’t get the smooth and little warmer hue that most Penon IEMs provide unless the source is adding it. From that standpoint it’s more accurate than the euphonic brand of mids you get with an IEM like Orb or the Legend. This benefits both instruments separation and tone accuracy which are really excellent in the price tier. Again, Serial is punching with pricier offerings if you’re looking for a more reference IEM.

Vocals are not emphasized and push forward but clear and articulate with good presence and there is no hint of sibilance. Both male and female vocals sound spot on. The Serial provides a lot of details as well, the tessitura of Pete Alderton “Malted Milk” or Big Daddy Wilson in “Thumb a ride” displayed both gravitas and all the nuances in vocal modulations. The Serial catched all the nuances of Elise Preys frayed vocals in Hollydays “Sensible” which makes it quite an emotional experience on the edge as it should, and in a very different smooth and dreamy track Dominique Fils-Aimé “Where there is smoke” is hypnotically beautiful and Serial impressed me greatly.


The Serial continues the trend that the Globe took vs the Orb. It goes even further and the 6mm PU driver does a fantastic job. In a day and age where EST drivers that dominate the flagship plane field which now trickles down to the mid tier with dual setup (ISN EST50, TSMR Land) it’s hard for the lower tier to keep up. The Serial shows that dynamic drivers especially with a specialized treble driver can hold their own.

I am pretty impressed with the balance Penon has found on the lower treble. The energy is excellent, meaning an engaging experience AND safe which means no harshness whatsoever. This is a hard balance to strike and I think it also has something to do with note weight. Piano notes are a good example and in The Hot Sardines “Comes Love (l’amour s’en fout)” the intro treble tone is spot on with the piano strokes featuring excellent weight and impact. This is where the best DDs do a better job than BA and EST in my opinion and Penon took advantage here. This translates to a very engaging and safe treble.

The upper treble is more extended than both the Orb and Globe and with more presence than both, granting more air than the previous Penon offerings including Globe. Detail retrieval, separation and imaging are really surprisingly good and you don’t feel like you’re listening to a 300$ IEM. If you factor that in with the overall balance between bass mids and treble you get a very impressive coherence and technical performance.


It’s really hard to believe how well Penon has grown its lineup in a short period of time, there is no argument than Penon does highly coherent tunings and the price to performance ratio is impressive across their whole lineup from entry to flagship. The lower tier IEMs that have been released from Sphere to Orb to Globe and now Serial are all home runs. Serial crowns this sequence with a daring 3DD design and come in with a splash in a segment very competitive segment.

If you’re looking for a reference IEM packing a well extended powerful and fast bass, an articulate midrange and an engaging treble both with accurate tone then at the asking price it’s hard to find a better proposition than the Serial.

Serial addresses the demanding audiophiles on a budget and it’s quite refreshing in a bullish market in the upper tiers. On top of this Serial will scale superbly with more power and an affordable desktop amp like iFi Audio Zen Can is a great option to enjoy all it can offer.

Listening notes
I spent approximately 60hours with the Serial, listening mainly on iFi Audio Go Blu but also FiiO M17 and Shanling M9 to check how Serial would scale.

Special Thanks
Thanks to Penon for providing a review unit of the SerialAs usual, this review is my honest opinion. No incentive was given for a favorable review. 


  • Hard leather carry case
  • Tips
  • Stock 8 wire SPC cable


  • 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

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