Periodic Audio C (Carbon)

General Information

Carbon is unique. Lab grown diamond meets Neil Diamond. The ultimate statement in resolution, with distortion below any other IEM we know of. Transparency starts and stops with C. Enough fun built in to make listening to any style a joy, but revealing enough to hear any detail buried in the mix.

The sleek, all-black construction just screams “I AM SERIOUS”. But the smiles it will induce will call that into question. Perfect with any source, from a tablet to a cellphone to a $10,000 rig. A big-screen experience with the clarity of a microscope. Micro and macro dynamics for an unrivaled listening experience.

The C (Carbon) IEM utilizes a lab-grown diamond layer (8 microns) on our own proprietary high-temperature polymer substrate. All components inside our IEMs was 100% designed and tooled in-house, resulting a totally unique product.

The sonic signature of the C IEM is an interesting mix of Ti and Be, with the enhanced bass response of Ti but the high-end extension of Be. It is well-suited for electronic music or anything with fast transients and extremely wide frequency response. C has the lowest THD of any IEM we have made, by a fairly wide margin.

All our IEMs feature polycarbonate bodies for high strength and zero resonance, custom front-and-rear tuned volumes, MIM logo caps, butyl rubber strain reliefs, and N48H grade magnets. Carbon sports a matte-black rear cap for the ultimate low-key, stealth look.

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Pros: Great clarity
Fantastic, deep, tight bass
5 year warranty
Cons: Build quality
The cable is the victim of a hostage situation
Sad cable :(
Questionable strain reliefs
Soundstage (depending on your preference)
This review was first posted on my website, A huge thanks to Dan Wiggins at Periodic Audio for providing these units.

  1. Introduction

Periodic Audio is a relatively new company founded in 2016, with a mission to create high-quality audio over all else. The Carbon is the latest and most expensive model in Periodic’s lineup, clocking it at $499. The other models in the lineup are Magnesium ($99), Titanium ($199) and Beryllium ($299). You can find them at

  1. Disclaimer

This set of Carbon IEMs was sent to me, very graciously, by Dan Wiggins on Periodic Audio, in exchange for an honest review, which I intend to provide. Dan also sent me the Nickel amplifier, which I’ll be reviewing soon. Both units are cosmetically blemished.

  1. Unboxing

The Carbon IEMs arrived in an unmarked cardboard box, which flipped open to reveal the pieces, as well as a small, presumably aluminum tin for storage. The packaging here isn’t anything spectacular, but it protects its contents well and presents them nicely enough. The packaging, much in the vein of everything else Periodic strives to do, is incredibly functional. I have no problem with this, as long as the audio performance can justify it.

  1. Build Quality

The build quality of the Carbon is similar to its packaging. Extremely functional and utilitarian. The shells are constructed from a sturdy-seeming polycarbonate, and the cable (while regrettably not detachable), is perfectly adequate. Fancy, braided, silver-plated cable this is not. But it gets the job done. My only qualm is the fact that the strain relief coming off of the earpiece looks a little worrying. I’m not thinking it will fail anytime soon, but it’s the only part of the product which I’m legitimately concerned about in terms of longevity.

  1. Comfort

The Carbon is very comfortable, provided you find the right tips. I know this goes without saying, but tips are crucial not only in terms of sound, but also for comfort. I eventually settled on the small, double flanged tips, but may swap them out for foams later. The light polycarbonate shells sit nicely in the outer ear and do not place unnecessary pressure on any ear feature. I have worn these for several hours at a time and never felt fatigue.

  1. Isolation

The isolation provided by the Carbon is above average. It is nowhere near Shure levels of isolation. But much of that is to do with nozzle length and a deeper insertion. Conversely, the Carbon has a much larger nozzle, but with the right tips, isolation still outperforms much of the competition. I took these on a short flight and forgot about engine noise for as long as I had them in. These are great travel earphones, and I am very happy with their isolation performance.

  1. Sound Quality
Overall, the sound of the Carbon is moderately V-shaped with slightly recessed mids and a clear, transparent-sounding tonality across the entire range.

  1. Bass
Definitely prominent in every mix. Although the bass is incredibly prominent, I’m not feeling too many issues with it becoming bloomy. Perhaps that has something to do with the material of the diaphragm? Overall, the bass response feels tight and accurate, with enough punch to satisfy most people. Very realistic sounding bass, with easily identifiable instruments. Listening to Kendrick Lamar’s King Kunta, the bass, while emphasized, does not overshadow Lamar’s vocals, and I find him to still be easily intelligible. This song is carried by its bass, and the C presents it with lots of energy and enthusiasm.

  1. Mids

Recessed. They’re not horribly back in the mix, but they definitely play second fiddle to the low- and high-end. Despite this, there is a high level of detail and articulation present here. Guitar slides sound great, as well as just straight-up guitars anywhere. Oodles upon oodles of detail here. Despite the elevated bass, miss stay crisp, clear, and very resolving. I would prefer them to be a little more forward, but they’re quite good as they are.

  1. Treble

The treble on the C is not peaky AT ALL. I can comfortably say that my treble tests did not make me wince, cry, or curl up in pain. Ever-so-slightly rolled off, they sit right where they should in the mix when fun is prioritized. Mainly because I would not consider getting stabbed in the ear to be a fun experience. These portray really satisfying cymbals and do a good job of representing even more difficult-at-times high-frequency sounds.

  1. Soundstage and Imaging

Yes, of course there has to be somewhere that the Carbon falls short. The soundstage, while providing a decent sense of space and accurately placing and imaging instruments and vocals, is very small. The closed-in nature of these makes much of a lot of songs quite intimate. For some people, this may be a dealbreaker, but the imaging and separation present in the C are very good. Soundstage is small.

  1. Conclusion
Fun. Fun. Fun. These little IEMs are fun. They’re light and comfortable, they’re bassy and unapologetic, they’re incredibly in-your-face, and I happen to like them quite a lot. Many reviewers are making the build quality seem worse than it is. Even if it is as bad as they make it out to be (which it really is not), Periodic has a 5 year warranty policy, which, in my mind, negates that altogether. The C is an incredibly fun earphone that I can find myself coming back to again and again for its big, boomy bass and clarity throughout its range. If you’re looking for fun, the C has you covered.

I'm a little curious to see how these sound compared to Periodic's other offerings...

Lance Rothchild
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Nice, although the cable is really a huge downside. On the other hand, I've seen someone with BTO mmcx pins PA Be, so let your imagination run wild :D.
Pros: Sound quality is excellent. Lots of great bass. Relatively smooth presentation. Extremely comfortable for long listening sessions.
Cons: Fixed cable. No choice on cables since its fixed and the included cable is quite microphonic.
Dan Wiggins from Periodic Audio contacted me about doing a demo of both the carbon and the nickel. I was provided the carbon in exchange for an honest and unbiased review, and I intend to provide just that.

About Me:
I have been in the audio hobby now on and off for a number of years now, and find myself drawn almost exclusively to IEMs. I really like the portability and quality you can get from a good pair of IEMs. I have gravitated mostly towards smaller single dynamic driver IEMs. Part of that is the bass quantity and quality that a good dynamic driver seems to provide over BAs, but also the coherency a good single dynamic driver can provide. I do not consider myself specifically a basshead, but I also really tend to like a good bassy sound as it is just more rich and full, so long as the bass does not overpower or take over the rest of the signature. I do not consider myself at the top of the audiophile world and often find a lot of the terms thrown about hard to follow. I have a general idea what I like, but at the end of the day, what is most important to me is does it sound good, and is it fun to listen to.

The carbon first came to my attention because of another IEM that I own and love, the Campfire Atlas. I originally had the Vega, and then moved on to the Atlas. And as much as I love the Atlas, they are big and heavy and obviously quite expensive so they are not always a pair I want to take everywhere with me. It is my understanding that with dynamic drivers, the driver material is a large component of what makes the sound signature what it is. Having heard great things about periodic audio, when I found they were also making a Diamond (or diamond like carbon) driver IEM similar to the Atlas, I was immediately interested.

About the Carbon:
In case any of you were wondering or have not seen the product page directly, I will include a bit of info about the IEM itself. The carbon is the newest flagship from periodic audio. It follows a similar design pattern to all the IEMs in their lineup. It is a barrel type IEM with a fixed cable. What differentiates it from their other IEMs is the driver material, being diamond (or carbon) in this case.

  • Price: $399 USD ($299 for a blemished version)
  • Frequency Response: 12 Hz to 38 KHz
  • Impedance: 32 Ohms Nominal
  • Sensitivity: 98 dB at 1mW in ear
  • THD: Less than 0.2% THD at 1mW
Packaging for these is pretty sparse. A relatively plain white box with information printed on it.


There is a flap that opens from the front to show some technical graphs about the IEM as well as more information (that can also be found on the product page on periodics website)


Inside the box is again a fairly sparse affair. A small tin that contains all the accessories, and some plastic to hold and "showcase" the IEMs in the box.


Inside the tin are a couple plug adapters, a 3.5 to 1/4" plug and a dual 3.5 airplane adapter. Eartips, 3 pairs of foam, 3 single flange silicon, and 3 double flange silicon. It is a nice selection of tips, and what you would expect, but it certainly doesn't go above and beyond. The tin is fine for storage, but I would not rely on it personally as it does not stay closed very easily. Perhaps that is due to being part of the blemished kit, but my recommendation would likely be to use a different carrying case.


My initial thoughts were that this is a relatively sparse kit. Its not very showy especially compared to some others I have owned. So first impressions were maybe not the best. But as I came to discover later, a flashy box and presentation here is just not a priority on these. And I actually think thats a very good thing. More on that later.

Build and Fit:
The IEM shells are polycarbonate. After coming from some other IEMs this actually felt a bit cheap at first, after all its just a plastic shell. However, the more I have used these I think its rather a positive. It keeps the carbon very lightweight. One of my major gripes with many other IEMs is that they are just not comfortable, especially for longer listening sessions. I find my ears are very sensitive to pressure points and some IEMs I have used can even cause pain after a short time. So having something lightweight is definitely a plus for me. And after a number of full work day long sessions, I can confirm that for me, these are one of the most comfortable pairs of IEMs I have used. And as Dan from Periodic has explained, polycarbonate is a good material to use as well since the sound does not resonate unnecessarily inside the shells, which should help deliver the sound cleanly.

The cable itself is fixed to the IEM. This seems to be a mixed bag, but one that I would likely file as a negative. At this price point, having the flexibility to change cables is almost a given these days. So it is a bit disappointing. There is the worry that if the cable fails, the whole IEM fails. The reasoning given by Dan at periodic is that current solutions are not great. And while I have never personally had an issue with MMCX or 2 pin connectors, I also do not often switch cables anyways. Plus, I believe there is a 5 year warranty on these, so periodic stands by their products.

The cable has a rubber texture and I have found that it is slightly prone to tangling, though I have never had any trouble with the small tangles I have seen. They have been minor. It does not retain shape at all which is nice, though it may not be ideal for wearing over ear. I personally prefer wearing down. However, this is also the source of my biggest issue with the non removable cable. It is quite microphonic. So I would likely not recommend these for working out. However when sitting still with music playing, its not that noticeable. I also use my IEMs for listening to tv shows and movies as well which often have a lot of quiet parts during dialog, and the microphonics can become very noticeable then even with relatively small head movements. Earhooks, or maybe a shirt clip would have been nice additions to help there for those that feel it necessary.

Overall, for the fixed cable, and build quality, the price seemed maybe a bit high. However, after I started listening, I think I have a better idea what periodic is all about. Sound and comfort.

As with any other IEM, fit and seal is important, both for sound and comfort. For these, I landed on using ML Spiral Dot tips. I found they give a great fit for me and the wide open nature of these tips really does not choke off the sound at all, and I found it gave the most air and sparkle in the treble (by small amounts).

I have been listening to these for about 3 weeks now on and off. There was no mention of burn in from the manufacturer, and I personally do not truly believe in burn in. What I do believe in is brain burn in, and being able to have some time to adjust to the sound. So I wanted to make sure I gave myself enough listening time, both for those who do care about burn in, but also just to make sure I felt really comfortable with the sound.

These are bassy IEMs. Definitely. They might even push to basshead levels. However after some time listening to them, I do not feel like the bass is too much. This is obviously in part personal preference. But the bass feels very controlled and balanced with the overall signature. These extend deep into the sub bass and have a good amount of rumble and enough oomph to really deliver that rich full sound that I personally crave. However for someone averse to bass, these are likely not the best option. The bass is also nice and tight, not at all sloppy or loose.

Mids are presented nicely, if maybe slightly recessed in the mix. I did not find them lacking though and vocals, both male and female were present in the mix and never got lost, and depending on the song could even really take center stage so to speak. Instruments were presented clearly and sounded as they should

Simply from reading the graph, it appears as though there is a big spike at around 5Khz. This may potentially be bothersome to some people, but I guess I am not too sensitive to it. Trebles have a nice sense of air, and come through clear enough. I do not hear any sibilance or anything that causes discomfort, and I would likely characterize the trebles as a bit on the smoother side of things instead of sharp or harsh. Which I believe helps in longer listening sessions to keep these from getting too fatiguing.

Soundstage and Other:
Soundstage is a weird one to me in that I was never really the most attuned to it and could never quite hear what some others described. It also seems like certain BA IEMs can have the edge here. I find it adequate, maybe not the most spacious or open. Not too much front to back depth, but a decent enough left-right separation.

Timbre. An elusive quality thats hard to define... From my understanding its just about how "right" or "wrong" it sounds. And these definitely sound right to me. Instruments have a natural feeling. Nothing sounds too over or under emphasized. They are really a nice sounding pair of IEMs.

This is another area I personally think maybe too much emphasis is placed on especially with IEMs that are usually quite sensitive already. Most devices out there (phones included) can provide enough power to these. Regardless, I was provided with a nickel amp as well and have spent most of my time listening through it. I did some a/b ing with it and my phone directly and the sound out of the nickel definitely sounded more full with a bit more sparkle and clarity up top. So it would seem these do respond decently well to some additional amping. But the changes were subtle, and I do not think anyone would feel the carbons are lacking when played directly from a phone.



Campfire Atlas: The carbon and atlas are obviously in much much different price brackets, with the atlas costing over 3 times as much as the carbon. Regardless, they share the same (or at least similar) driver material and considering it was my driving interest in the carbons it would be wrong not to compare them. The atlas has a stainless steel shell and is quite heavy. The carbon is much more comfortable to me. They seem to share a similar overall sound signature. Bass on the Atlas seems to be a bit more enhanced giving the atlas a slightly fuller sound. Treble on the atlas also seems to extend a bit further giving the atlas a bit more of a feeling of clarity. Atlas still feels like the superior IEM in terms of sound, but overall its relatively close. The atlas does have a more premium feel and premium feeling cable, and obviously the option to swap them out, but again it is over 3 times the price when bought new. And I would say the carbon actually does a decent job holding its own here.

Final Audio E5000: The E5000 is in a slightly different price bracket as well, coming in at about $270. The only real similarity here is that I would classify them as another mid range single DD. But the E5000 does not share the same driver material, and has a significantly smaller DD than the carbon. Before the carbon, the E5000 has been my more affordable DD in my kit. Sound wise, the E5000 is more mid focused than either the atlas or carbon. Bass is still present on the E5000 but it does not seem to extend quite as deep, yet still provides a rich full sound. Trebles seem like they extend well, but there is not as much sparkle or clarity as the carbon. Its a smoother sound. The semi-open design also gives them a slight edge in soundstage and air, but that also means sound leakage and worse isolation. Their small driver and small size also make them lightweight and super comfortable just like the carbon. Unlike the carbon, the cable is removable, and as nice as the stock cable is, it is also quite microphonic like the carbon. But the E5000 does include earhooks which help, and earhooks might have been a nice addition to the carbon package. The E5000 is less sensitive than the carbon and requires quite a bit more power to drive, and may almost require a separate amp or dac/dap to really get the most out of them, making them potentially less portable.

Conclusions and Final Thoughts:
I want to talk about the "blemished" version I received. There are a few small gaps between some of the connectors that might not necessarily be there in the finished version. And a couple small nicks (such as on the backplate) that otherwise might not be there either. But overall, they look quite nice and I do not think anything is really taken away from the quality. They certainly sound wonderful. For those who the price might be a bit high for what is included, the blemished version is $299, which I think represents a great value for these if you can live with the minor aesthetic imperfections.

The right and left shells for all intents and purposes are identical. This can make figuring out which is right and left difficult. The only identifying marks are the grills. Black on the left, and a red grill on the right. I have seen others post that they have added something to the cable to identify them, but this is an area that could certainly be improved. Being able to identify right from left easier without having to look inside the tips would be nice, or even a raised bump on one to differentiate by touch would be nice.


They are also very nice and portable. And fit perfectly in this small case I found way back from amazon, along with the nickel and the audio and charging cables. This has become a very nice and very portable kit for high quality playback out of my phone.

As I mentioned above, first impressions (just on looks and feel) were not the greatest. These are lightweight and feel a bit cheap in the hand. But are supremely comfortable. But sound quality is also really great. And thats the rub, these are unassuming, but focus on the most important things. Comfort and Sound. Periodic seems to have their priorities straight. Who cares about the box or the looks when they are in your ear. Sound quality and comfort are much more important.

So, I land at 4.5 stars here. I think they sound great and are super comfortable. And they likely punch above their price point strictly in terms of sound. But for the price there are a few things that would otherwise be expected, mainly the fixed cable. Its flexible and nice, but quite microphonic, and since its fixed, there are no other options there. The issues mentioned are not necessarily trivial, and at this price point a more premium build with detachable cable might be expected. But I think for the sound, comfort, and portability these provide, they are excellent and I would not hesitate to recommend them to anyone who might be interested in this type of sound signature.
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@josesol07 Thanks! As for which, I would personally probably take the carbon. Its more V shaped and thats more exciting of a sound to me, and works well for rock. The E5000 is super smooth, so not quite as much energy. But thats where preference comes in. Some days the smoother sound is preferred. The bass on the carbon is really tight and well controlled, and on the E5000 its more balanced, so I dont notice any real bleed on either.
@mashuto, appreciate your feedback. Forgot to ask, is there any sound leakage out of the Carbons?
@josesol07 They are vented so I imagine there is a tiny amount, but not something I would worry about.
Pros: Syrupy Mids, Ultra-Coherent, Full-bodied sound, Imaging is precise
Cons: Weak cable + strain reliefs, Soundstage feels a tad closed in.
Dan from Periodic Audio has graciously sent me a review unit of the C and the Nickel amplifier for honest reviews. This review is in no way sponsored and I will be honest about my feelings surrounding this product. . This is my humble opinion. YMMV!

We've definitely been down this road before, but if you're interested in learning more about Periodic Audio, check out my review for the entry-level, Periodic Audio Mg.

All you need to know is that the Carbon uses a unique, lab-grown, diamond-like carbon transducer. Because it is impossibly hard to manufacture your own, in-house "dlc" drivers, the C is the most expensive iem that Periodic Audio currently carries, at $499 USD. This is certainly a statement piece.


Driver Type: Diamond-like carbon dynamic transducers
Connector: Non-detachable
Nominal Impedance: 32 Ohms
Frequency Response: 12Hz- 38kHz



1 X Periodic Audio C
1 X Periodic Audio Tin Case
3 X Double Flange Silicon Eartips (S, M, L)
3 X Foam Eartips (S, M, L)
3 X Single Flange Eartips (S, M, L)

Like the other iems in their current-lineup, they feature the same exact accessories set. Nothing new, but as per usual, there is more than enough out of the box. Again, the tin's interior is way too small for the typical "three finger curl" technique (BOO).

Design, Build and Comfort:


I sound like a broken record but comfort wise, there is little to whinge about. Like all their other iems, the C features a barrel-style housing that fits snugly in the ear with the right pair of tips. Its mass is negligible and I had no qualms wearing it for hours on end. All Periodic audio iems are incredibly comfortable thanks to their light, poly carbonate shells and straight down cable. I'd suggest users to be gentle with the C and handle them cautiously; their cables don't exactly inspire confidence.

Nothing has changed, including the painfully thin cable. The strain reliefs are exactly the same; they don't feel substantial enough for the daily commute. However, Dan from Periodic Audio has stated that the company is working on a detachable cable solution that is superior to the industry standard MMCX and 2-pin CIEM connectors. Fingers crossed, hopefully they integrate this new system in the near future.

This time, the C features a black-end cap for a sleek and understated look. I dig it.

However, I still think compared to the likes of Campfire Audio, at this $399 USD price point, I expect a build quality reflective of its premium price tag. The plastic shell is fine but the cable needs alot more tweaking.


Star Track: Dry the River: New Ceremony (Acoustic)

If the spirit has left you baby
Don't lie to yourself
Put them old records on
And admit that it's gone somewhere else
Coming to this review, I was using the Mg's as my daily accompaniment for long-listening seshes till the wee hours of the morning. The C replaced them for the past week and the sonic improvements are easily picked up on (as expected of an earphone 4 times more expensive).

First of all, there are some similarities between both earphones. The Mg and the C share a voluptuous, bass response that is bloated in the mid-region. However, the C practices more restraint, with the mids mostly unclouded by that assertive bass-hump.

There were definitely certain acoustic presumptions after demoing the Campfire Audio Atlas and Vega's awhile back. Three of these iems share similar driver-tech and I expected them to share similar sonic qualities.

I am convinced that out of all the three DLC iems, the Carbon is both the cheapest and the most polished.

The Carbon is dark, smooth and velvety. It is inviting and pairs well with many genres of music.

The highs are slightly muted but it carries enough detail for it to sound "coherent".

The mid-range is the star performer. It is organic, smooth and the transient shift from upper to lower-mids is just buttery smooth. Everything is perfectly balanced and nothing sounds offensive. It is refreshing to have an iem with only a single driver at its core. It is incredibly cohesive and nothing seems out of place in the mix.

Bass notes are definitely accentuated and some might consider it overpowering. But that bloom elevates acoustic tracks with a "chamber" or stage-effect that adds body and definition to string instruments with a slow-decay.

Treble is free of sibilance, masking odd-harmonics that can easily cause listener fatigue.

Sound-stage is unfortunately, rather intimate and noticeably narrower in size compared to the Periodic Audio Be. It is definitely a step down.

However, imaging is sublime. Everything is well placed in each track and it is easy to notice a minutiae of new-elements never heard before in cheaper iems. Because of its ultra-clean background, it is easy to distinguish audible cues and the positioning of each instrument. With Dry the River's New Ceremony, each vocalist is presented with studio-like precision. Using your ears as a 3-D reference ball, each vocalist gently envelops you with their sonorous falsettos from all sides, slowly coalescing into a harmonious mix of voices.

At 32 Ohms, it is easily driven out of any source. However, I have been using it with the Periodic Audio Nickel and it is match made in heaven. This thing packs power and I will be reviewing this in the near future. The C was also used with my Shanling m0. Nothing much can be said except it is certainly a more "audiophile" source compared to my Pixel 2 XL.


To quote my previous review of the Mg, the "Cable" needs to GO. I expect a premium build quality if I am paying $499 USD. I understand that Dan doesn't like to use any sort of metal chassis because they have a tendency to ring and amplify unwanted resonances. From an engineer's perspective, it is perfectly understandable. As long as the cable is replaced with something more durable, I'll be a satisfied customer.

Apart from those minor details, the Carbon is a flagship IEM. Syrupy and ultra-coherent, the C is a a smooth operator with the sonic capabilities expected of an earphone in this price bracket.

Spare me the balanced armature arms race. Sometimes, less is more. And the carbon reaffirms that sentiment.

For people interested in purchasing the iem, you can purchase the earphones directly from them.

Periodic Audio:

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