Periodic Audio Carbon
James Tan 2020

Periodic Audio Carbon Review

The Periodic Audio Carbon is the company’s flagship  IEM featuring a carbon (Diamond) membrane single dynamic driver. It is priced at $399.

Disclaimer: The Periodic Audio Carbon sent to us is a sample in exchange for our honest opinion. We thank the team at Periodic Audio for giving us this opportunity.

To read more about Periodic Audio products we have previously reviewed on Headfonics, click here.

Note, this review follows our new scoring guidelines for 2020 which you can read up on here. 

If you have been to CanJam and spotted some people in lab coats, they are the team from Periodic Audio. This is a U.S. based company that features a cool lab theme for all their exotic materials-based products.

The team claims to have over 140 years of combined audio-centric development experience for dozens of high-end brands before the Periodic brand was established. All IEMs from Periodic Audio carries a certain elemental theme and consistent down-hanging design for easy, comfortable wearing.

The latest version of this theme is their new flagship universal monitor, the Carbon. This is an IEM priced at a mid-fi level of $399 and has some very unique materials mix consistent with how Dan and the team like to pitch their drivers.

Periodic Audio Carbon

Tech inside

”Made From Diamond, Because Music Is Forever!”

The Carbon IEM utilizes a lab-grown diamond layer (8 microns) on a proprietary high-temperature polymer substrate that forms the driver membrane. I would suspect they are probably using CVD (Chemical Vapor Deposition) or similar technologies to create a thin layer of the element plated on a host membrane.

From Periodic’s information, the sonic signature of the Carbon IEM combines the traits of the other models, Ti and Be, putting together the enhanced bass response of Ti and the treble extension of Be.

Periodic explains that the Carbon is well-suited for electronic music or anything with fast transients/ extremely wide frequency response, and we will check this in the sound test below. The Carbon also has the lowest THD amongst all Periodic IEMs by a fairly wide margin with a pitch of being their lowest distortion IEM made to date.

Periodic Audio Carbon


The Carbon uses polycarbonate for its very simple and plain body to achieve high strength and the claimed zero resonance. The design consists of custom front-and-rear tuned volumes, metal injection molded logo caps, butyl rubber strain reliefs, and N48H grade magnets.

You will need to hark back to your high school chemistry class memories to read their descriptions but it is a lot of fun learning about what exactly they put into making this IEM.


A matte-black rear cap fuses on the satin-finished body for an ultimate low-key, stealthy look. As Periodic Audio explains, there is still some good contrast when some parts are matte and some are more glossy.

The L and R side of the IEM looks identical but hidden in plain sight there is a cool design, looking inside the tips the mesh is colored red on the R side of the IEM for you to identify which side is which. Without this,  the L and R side would be completely identical.

There are no swappable cables so we don’t have the chance for cable rolling and balanced connection, but hardwiring always promises better conductivity.

The Carbon looks scarily simple and plastic for its price but it is incredibly light and easy for anyone to wear, The design also allows easier after service, with an impressive 5-year local warranty in the US and 2 years warranty for other countries.

Comfort & Isolation

The Carbon is incredibly light with its full plastic housing in a satin finish, which feels a bit like hard rubber with a good grip when you touch it.

There is some slight driver flex when you insert the earphone but not too noticeable. The form factor promises sweatless easy wearing and fits everyone like what Periodic Audio has claimed, zero stress with moderate isolation and you could wear the Carbon over-ear too.

You may experience some microphonics but you could always wear it over your ears.

Periodic Audio Carbon

Package and Accessories

The Carbon comes in a fairly plain cardboard box with an explosion chart on top, beneath the front cover you will see the frequency chart and explanations on the materials used for the design.

Opening the cardboard outer packaging you will find a metallic tin inside and unscrewing it you will find 3 sets of foams. The break down is as follows for the tips:

  • 3 sets of normal tips
  • 3 sets of double flange in S/M/L sizes

A plane adaptor and a 6.35mm converter jack are also included for flights or to connect to amps/ other outputs. The same packaging style applies for the Nickel amplifier and everything is simple and minimalistic.

Periodic Audio Carbon

Sound Impressions


As this is a dynamic driver based IEM I am giving it some good run in time for the drivers to break in and the Carbon is tested on various outputs with different level of power including cellphones/tablets with and without the Nickel amplifier, MacBook and various DAPs including the FiiO M11Pro/M5, the Hiby R6 Pro, and the Oriolus DP100.

The Carbon has a V-shaped tuning that pushes forward the bass rumble and upper treble for clarity.

The sound aligns with the FR curve printed in the inside of the front cover and you can hear the bass elevated and the mid-range being recessed. The treble is lifted around 3kHz and 7kH followed by a sharp roll-off in the treble that takes away all harshness, quite obvious when you play music loud.

Overall, the Carbon sounds clean and peaks slightly in the higher register with a fast, full-bodied bass response.


On tablets and cellphones, the Carbon requires below 50% volume to sound loud listening indoor, there is a hint of warmth but not exceedingly bassy and you can feel the drum kicks fully with good clarity and power.

The lower bass presence is strong, yet Carbon manages to preserve good details with fast attack, which makes it comfortable and not boomy for all genres of music. Overall, a good balance is achieved between ample bass punch and dynamics resolution, especially when you feed the Carbon good power.

Putting the Carbon on the DP100 the bass gets tighter and more controlled with better extension revealed. Amping definitely helps opening up the Carbon treble as well as ensuring the mids articulation is smoother.

The slightly warm, full-in-bass tuning gets along well with pop songs and blues, gives 70s pops a good lift in clarity and dynamics, and sounds juicy with acoustic guitars and drums.


The FiiO M11 Pro strengthens the texture in the treble, tightening the bass punch whereas the R6Pro gives it more dynamics and air. These are the areas that would greatly improve when there is more power. However, you will still hear the treble rolling off when amped. The Carbon never gets peaky but it does take away some sparkle that helps render larger staging without a good source.

As mentioned, paired with better amps the bass articulates more swiftly into the lower mids. It does not bleed into the slightly recessed vocal which is boosted around 2kHz for clarity.


Good depth is rendered but with a slightly recessed vocal. Darker voices may sound a bit boxy and nasal tones can be heard clearly that may give better weight to some lighter voices.

While there is a strong 5-6kHz presence hi-hats, cymbals, and other details in percussion instruments are brightened up and cleanly presented. These higher pitched instruments and vocals sound smooth and rounded. In most cases they never sound hot due to the sharp roll-off followed by a lifted treble peak which eliminates resonances and harshness.


Carbon renders an oval-shaped, small classroom-sized stage which has the vocal projected slightly distanced to create more depth. This contrasts with the intimate, close impacting bass kicks which sound quite forward.

Instrumental separation is good with a fast bass decay. However, the roll-off that kills off sibilance takes away some air and limit the openness. While isolation is not its strength due to the fit, the tuning actually compensates ambient noises well and sounds quite balanced outdoor on phones and tablets.

When listening indoor the bass impact is on the strong side and draws near bass intensive instruments, making the perceived sound-stage narrower. You can pair it with a stronger source for a more open sounding presentation.

Periodic Audio Carbon



32ohm and 98dB sensitivity marks the Carbon as a fairly easy to drive IEM. The higher impedance gives it an excellent background noise control and easier to work with sources that have a higher gain. Stronger sources will be able to deliver better punch and resolution with some additional voltage.

Small DAPs like the FiiO M5 and cell phones will still be able to drive the Carbon with a fair amount of dynamics. However, amping it will definitely give it better performance especially the bass control and texture.

Hooking up with amplifiers

You can easily hook up the Carbon to the Periodic Nickel or another portable amplifier which adds more dynamics and air. This could touch up the whole experience and I recommend tube amps to be paired that can make vocals sound smoother and the bass punchier.

The Carbon responds well to higher gain/power to sound more extended and detailed. The vocal gets more rounded and the bass is more controlled than on smaller outputs, unveiling more details in the sub-bass and higher treble region. Overall, it helps the Carbon to sound more balanced and dynamic and I enjoy the Carbon much more when it is sufficiently powered.

Periodic Audio Carbon

Selected Comparisons

Fiio FA7

The FiiO FA7 is a 3D printed IEM with a futuristic faceplate design priced slightly cheaper than the Carbon. Both IEMs offers good bass punch with upper vocal clarity when powered sufficiently.

The resolution highlights the sound of the FA7 while its tuning is quite bass intensive and lifted in the upper treble alike the Carbon. The FA7 focuses on resolving power and clarity, being more easily driven to full performance than the Carbon which  sounds more rounded in treble and fuller in the bass.

The upper vocal range is also more forward on the Carbon than the FA7 but the FA7 has a better extension, yet it doesn’t scale as nicely as the Carbon with amplification and larger gain. I believe it is the driver nature (dynamic in Carbon) that gives it more potential to scale up with amplification.

Final Audio B3

The Final Audio B3 has an exquisite mid-treble focus that penetrates well into the upper frequencies, with upper mids and the 5-6 kHz range lifted. This is what I find very alike the Carbon but B3 has a lighter punch in the lower register.

The B3 works very well with fast-paced electronic music and songs with light voices yet it lacks the impact and energy in the bass that the Carbon carries. Such gives me the feeling Carbon does better for electronic music/ trance/ EDMs with its fuller low end, but it couldn’t beat B3’s crystal clear and clean vocal that extends much more effortlessly.

Periodic Audio Carbon

Our Verdict

The Periodic Audio Carbon is a stealthy, ultra-light IEM which comes with an extra-long warranty and a rugged build.

Overall, the sound is fun and dynamic has good synergy with a common source and different genres of music. The rather fast bass decay also clean and pronounced upper mid-range aligns with my imagination how a “carbon” driver will sound, and luckily it is not harsh or thin in the bass.

It works surprisingly well with streaming contents and old folk songs/ EDMs for daily commutes and the form factor allows you to pull it off in no time. If you think over-ear IEMs troubles you and have good juice in your setup, there would be some good chemistry!

Carbon Technical Specifications

  • Frequency Response 12 Hz to 38 kHz
  • Impedance 32 Ohms nominal
  • Sensitivity 98 dB SPL at 1mW in ear
  • Power Handling 200 mW continuous
  • Peak SPL 121 dB
  • THD Less than 0.2% THD at 1mW
Periodic Audio Carbon
Overall, the sound is fun and dynamic has good synergy with a common source and different genres of music. The rather fast bass decay also clean and pronounced upper mid-range aligns with my imagination how a “carbon” driver will sound, and luckily it is not harsh or thin in the bass.
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