Periodic Audio Carbon Review: The End-All-Be-All

Aug 18, 2019 · 8 min read

Periodic Audio is a small audio company from the US. They take a measured, scientific approach to building audio products, blending their artistic senses with a wealth of design and engineering expertise. They’ve released a number of IEMs, most recently releasing their new flagship, the Carbon. This IEM is special in many ways, not the least of which is its diamond-based diaphragm. Naturally, this comes with a price-bump. Is the exotic diaphragm material and touted increases in performance enough to justify the new price tag? Lets find out!

About My Preferences: Heads up, I’m a person! As such, these words are my opinion, and they are tinged by my personal preferences. While I try to mitigate this as much as possible during my review process, I’d be lying if I said my biases are completely erased. So for you, my readers, keep this in mind:

  • My ideal sound signature would be one with competent sub-bass, a textured mid-bass, a slightly warm midrange, and an extended treble.
  • I have mild treble sensitivity.

Source: The Carbon was tested in the following configurations:

  • LG V40-> earphones
  • Hidizs AP100 3.5mm out -> FiiO A5 3.5mm out -> earphones
  • HiFiMAN SuperMini -> earphones

All music was served as MP3 @320Kbps or as FLAC.

Tech Specs

  • Frequency Response: 12 Hz to 38 kHz
  • Impedance: 32 Ohms nominal
  • Sensitivity: 98 dB SPL at 1mW in earPower
  • Handling: 200 mW continuous
  • Peak SPL: 121 dB
  • THD: Less than 0.2% THD at 1mW
  • Cable Length: 1.5 m
  • Mass: 2.8 / 9.3 g (IEM/Set)

Sound Signature

Sonic Overview:

The Carbon has a V-shaped sound signature with a powerful-yet-controlled lower register. It maintains a warm midrange, extended treble, and clear timbre.

Treble: Songs used: In One Ear, Midnight City, Outlands, Satisfy, Little One, Show Me How To Live (Live at the Quart Festival)

According to Periodic Audio, the Carbon owes much to its cheaper siblings, as it took inspiration from the Ti for its treble tones. The Carbon extends very, very far into the upper treble, resolving an enormous amount of fine-grain detail without sacrificing smoothness or introducing sibilance/sharpness. The Carbon’s most impressive treble-bound feature is its uncanny ability to stage high-hats. Across literally my entire test suite, I was able to make out every single slam. I mean that in the literal sense, I triple tested this claim. It’s a feat that only one other IEM (the Da Vinci X, a $2499 10-BA IEM) has ever come close to accomplishing. This is a testament to The Carbon’s very keen detail pickup and incredibly low distortion levels.

Midrange: Songs used: Flagpole Sitta, Jacked Up, I Am The Highway, Dreams, Too Close, Little Black Submarines

The Carbon’s midrange is recessed with a warm lower component. It presents a very wide tonal range, enabling it to preserve the fit-and-finish of the songs played through it. I found that the Carbon’s quick drivers allow it to resolve complex tones and busy scenes with a startling level of precision, something I was not prepared for during my initial listening session. I actually had to get used to the deep layering that the Carbon presents as songs I had listened to years took on a new level of depth. The multi-faceted choruses of presented a wide breadth of tones for the Carbon to resolve, and it followed through masterfully. The same can be said for The quick transition from a lonesome intro into a massively-staged chorus was handled cleanly and with precision.

Bass: Songs used: Moth, Gold Dust, In For The Kill (Skream Remix), War Pigs (Celldweller Remix)

Full and weighty, the Carbon’s bass is one that I have been seeking out ever since I got my hands on the Rose Cappuccino Mk II’s a couple years back. It slams you with impact during explosive bass drops in songs such as and , washes over you with sub-bass during extended bass lines in songs like , articulates the plucking of bass guitars clearly in , and accentuates the presentation of otherwise shallow songs generally. The Carbon gives me the ability to point and say “yes, of course you can have an audiophile IEM that’s bass heavy!”, a claim that would be otherwise difficult to substantiate. While it doesn’t move quite as much air as the aforementioned quad-driver IEM, the Cappuccino Mk. II, it comes really close while avoiding the somewhat sluggish and, at times, uncontrolled nature, of other bass-heavy IEMs in this price bracket. I played everything from Country to Classical through the Carbon to try and detect any hint of the bass overwhelming the details in the midrange and could not hear even one instance of such an event occurring.

Packaging / Unboxing

As is customary with Periodic Audio’s Products, the Carbon arrives in a plain, information-dense box that gives you a nice run-down of its physical and sonic properties.


Construction Quality

The Carbon’s shells are made out of a polycarbonate specially designed to minimize resonance (and with it, distortion). Its bass ports are located on the top of the shells, while the non-detachable cables are fixed to the bottom, as is Periodic Audio tradition. The back of the shells display the Carbon’s black shell caps, muting the two-tone style that was delivered on the previous three IEMs delivered by PA. On my unit, the right bass port appears to have some plastic debris (or maybe misplaced glue) showing along the very edge in small quantities. The shell cap’s gap is very marginally uneven when comparing between the left and right, and there’s very small blemishes on the rear of the shell where they were cut from the injection tray. None of these minor aesthetic flaws affect the structural or functional integrity of the Carbon, but as Periodic Audio moves further and further up the price ladder for its new products, they need to make sure to decrease manufacturing tolerances for them.

The Carbon’s nozzles are quite good. They are average in length and have a well-defined lip that keeps its eartips securely fixed in place. Just beneath the edge of the lip is the debris filter. They’re conveniently colored to help you distinguish left from right and have a spiral-patterned perforation. Its a unique style that doesn’t show up in many other products.

I have very little room to actually levy criticism against what I consider to be some of the greatest audio products on the market, but PA, please, at least give us thicker cables or something. The ones currently being used across the lineup are certainly not going to just break prematurely, but there’s something to be said about the peace of mind that accompanies the extra durability afforded by higher-quality cables. If we can’t swap the cables out, I’d at least like to see some further fortification of the one I am stuck with.

The actual design of the Carbon’s shells is actually pretty good, all nit-picking and griping aside. Since it weighs practically nothing, the Carbon can survive reasonable drops and falls with little to no damage. It is also not prone to being crushed, though like all plastic-shelled IEMs, I heavily caution from exposing it to crushing forces such as those in a filled backpack or purse as over time you will inevitably break your audio device, regardless of how sturdy it may be.


I find the Carbon, like its predecessors, to be comfortable. I have the added bonus of already knowing what size eartips to use with them, as I’ve had three years or so to figure it out with their other IEMs, but you should have very little difficulty figuring it out given the good selection of sizes included in the box. I was able to routinely use the Carbon for 3–4 hours at a time at work with little-to-no discomfort. Further, the Carbon does an outstanding job nullifying external noise with its dense foam eartips. Walking down the busy and crowded streets of downtown Chicago every morning and rush hour has demonstrated that ability quite well.


Inside the box you’ll find the following accessories:

  • 1x Tin carrying case
  • 1x Airline adapter
  • 1x 1/4in adater
  • 3x Foam eartips sets
  • 3x Double-flanged eartip sets
  • 3x Silicone eartip sets

The accessory kits of each PA IEM are identical. I don’t mind this one bit as PA delivers high-quality and functional accessories without giving a bunch of useless junk that will end up taking space in your drawer before inevitably being thrown away. I had no problem finding a pair of eartips to use comfortably with the Carbon and have found the carrying case to be a great and portable solution to safely storing the Carbon.


It may seem that reviews these days use hyperbolic language to describe products that are merely “enjoyable” — I assure you that this is not one of those situations. I truly and firmly believe that the Carbon is the end of the line for my personal tastes and unequivocally recommend it as my #1 choice for dynamic driver IEMs for the bass-loving Audiophile. I’ve been using it as my daily driver for the past two months and I don’t see that changing any time soon. While more iteration on the manufacturing process could be used to increase the quality of the Carbon’s fit and finish, such a small hiccup falls completely to the wayside of the Carbon’s immense sound quality. So if you
are someone looking to take their first big steps away from consumer audio, or an audiophile who is seeking a new top-tier dynamic-driver IEM, I highly recommend you check out the Carbon.

As always, happy listening!

Resonance Reviews

Resonance Reviews is a publication dedicated to bringing…


Written by


Tech enthusiast. Audiophile. PC builder. Reviewer. Writer.

Resonance Reviews

Resonance Reviews is a publication dedicated to bringing fair and rich reviews to the table while skipping the fluff that reviews usually have. We are dedicated to providing you the best in audio hardware reviews. Want to get in contact? Email us:


Written by


Tech enthusiast. Audiophile. PC builder. Reviewer. Writer.

Resonance Reviews

Resonance Reviews is a publication dedicated to bringing fair and rich reviews to the table while skipping the fluff that reviews usually have. We are dedicated to providing you the best in audio hardware reviews. Want to get in contact? Email us:

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