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Periodic Audio C & Be Review – Contrast

Pros –

Outstanding bass quality, Smooth yet detailed treble, Be has excellent midrange timbre, Excellent ergonomics, Highly portable, 5yr warranty

Cons –

The C has a thin and shouty midrange, Intimate soundstages, Thin fixed cable

Verdict –

The prowess of Periodic’s in-house developed dynamic drivers is showcased first and foremost by the Be and C whose straight-forward design and resolving sounds will appeal to audiophiles and consumers alike.

Introduction –

Periodic Audio is an absolute odd-ball company; self-funded by a handful of audio specialists and executed with exemplary focus. Their core ethos revolves around portable audio, minimising the bulk of their product’s form factor while maximising sound quality. What Periodic have set out to do, is not to reinvent the wheel, but optimise it for daily life. Their products are also differentiated from the majority through their implementation of high-quality dynamic drivers, designed and tooled in-house. Their product line is themed, as their name would suggest, around the periodic table of elements. Each earphone carries an identical housing designed to create an optimal acoustic environment for their custom dynamic drivers. It’s also curious that the company does zero tuning instead, letting the metal coating of choice dictate the resulting sound. At present, they offer 4 models ranging from the affordable $100 USD Mg to the $399 USD C. All are assembled in the USA and carry the exact same design with only different coloured faceplates denoting their identity. With that said, we’ll be diving into how their latest and most potent earphones, the Be and C perform. See Periodic Audio’s website for more info and store links.


Disclaimer –

I would like to thank KS Distribution very much for their quick communication and for providing me with the Periodic Audio Be and C for the purpose of review. All words are my own and there is no monetary incentive for a positive review. Despite receiving the earphones free of cost, I will attempt to be as objective as possible in my evaluation.


The Pitch – 

Beryllium foil diaphragm 

“Beryllium is among the least dense stable metals, but also has among the highest Young’s modulus values (a ratio of the stiffness) and speed of sound.  This results in high efficiency and extremely low distortion as the diaphragm does not bend on its own, moves homogeneously, and dissipates internal energy very well.”

The Be implements a 100% pure beryllium foil diaphragm with bonded PEEK aka thermoplastic surround. And this, similar to the C’s carbon driver, is an excellent material for earphone drivers on behalf of its exceptionally high Young’s ratio/hardness which permits lower distortion at high frequencies and alongside the ability to use less material for a lightweight and quick-accelerating diaphragm.

Carbon Dynamic Driver 

“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.” – Periodic Audio

Periodic implement a carbon driver into the C similar in construction to that used by many flagships. With an 8-micron thick diaphragm combined with the exceptionally high rigidity of its carbon complexion, the C promises a wide frequency response and fast transients in addition to the lowest THD of Periodic’s in-ear line-up. Theoretically, the properties of the material in addition to its lightweight permit quick acceleration of the driver which, in addition to high rigidity, permits low distortion at high frequencies.


With differing materials standardised by an almost identical housing design, Periodic’s earphones all offer sounds of differing characteristics. As such, though the C may be the most technically proficient, it may not necessarily suit the widest range of listeners based on its signature. As such, Periodic offer a tool on their website where the prospective buyer is able to input their top 3 preferred genres of music and the most suitable model is suggested for them.


Unboxing – 


Both earphones feature simplistic packaging centred around the periodic table of the elements in addition to the qualities of their dynamic drivers. Inside are the earphones within a stylish metal tin. The tin is fantastic, perfectly fitting the earphones coiled around 4-fingers without requiring them to be kinked and folded in abstract ways.


Foam inserts prevent scratches too, brilliant. Periodic audio also include a slew of accessories, 3 pairs of silicone ear tips, 3 pairs of dual flange tips and 3 pairs of foams. Additionally, aeroplane and 1/4″ adapters can be found within the box, very handy additions.


Design –

Whether paying $100 USD or $400, the buyer receives the same bullet-style design. True to Periodic’s intentions, they’re compact and traditionally shaped in-ears that will be instantly familiar to any IEM user. It should be noted that they have a polycarbonate construction that’s more resilient than normal plastics and is said to mitigate resonances. The earphones have injection moulded metal end caps, the C being outfit in a clean and stealthy black and the Be in bronze with accompanying bronze vent for a congruent aesthetic. Orientation can be difficult as it is only denoted by the colour of the grill beneath the tip, with right being red, left being silver. A bump on the strain relief would have aided this process.


Though plain, the housings are immensely functional, however, the cable is likely to be most contentious. In particular, it’s a fixed unit so any breakages will require replacement of the earphones or third party recabling which can get pricey. The cable itself is also mediocre with a basic rubber jacket and dainty construction. The butyl rubber strain reliefs on the earpieces add some durability, however, the jack has no relief. Though I understand Periodic are gunning for optimal portability, such a compromise to the potential longevity of the product will likely be a deal-breaker for some prospective buyers. Nonetheless, a 5yr warranty is reassuring and great sportsmanship on Periodic’s behalf.


Fit & Isolation –


Regardless, with such a traditional design combined with rounded edges and long nozzles promoting a deeper fit, the Periodic IEMs reward with excellent wearing comfort and seal. They also have the ability to be worn both cable up and down based on user preference and I do know many users who aren’t comfortable with over-ear IEMs. The compact housings barely contact the ear and formed no hotspots over extended listening in my testing. As the cable is fixed and the seal is strong, I did personally prefer to route the cables over my ear to avoid microphonics, yet as the cable enters near the rears of the earphones, it does push the cable away from the face when worn cable down too. Furthermore, the strong seal does result in a noticeable driver flex, however, this did not cause issues during my testing either. Isolation is very good for a vented dynamic driver earphones if not quite as attenuating as a fully-sealed BA earphone. Still, they are easily sufficient for public transport, especially when factoring in their bassier sound.


Sound –

Periodic C 

Periodic C

Tonality –

The C has an L-shaped sound with prominent sub-bass and vocals before a smoother top-end. Its most prominent feature is a large dip from the mid-bass through to the centre midrange, which creates a very clean presentation with great contrast and separation. The tone is a touch cool but not metallic while body is thin, providing the impression of transparency and clarity. The high-end meanwhile features a dip around 6-7KHz to avoid over-articulation and sharpness, before another small bump in the middle-treble that imbues pristine clarity and a pleasing sense of air. This is evidently not a balanced, linear or accurate sound, but one that works in isolation and is underpinned by very sound technical ability.


Bass –

Lows represent all the great attributes of a great dynamic driver earphone, it is a stunning performer. Sub-bass extends very well which alongside large emphasis, produces physical slam and rumble at the very bottom with that sensation of moving air that BA’s just don’t give you. Bass then slopes sharply into a recessed lower-midrange, leaving a fairly neutral mid-bass and recessed upper-bass. The result is a very clean low-end with a natural but not overtly warm tone and slightly enhanced note size. This additional fullness saves this earphone’s presentation alongside the qualities of its driver.

Control immediately stands out; from bottom to top there is precision and definition. Even with emphasis, sub-bass is tight and agile like a well-integrated subwoofer. Meanwhile, mid-bass is very defined, aided by a perfectly neutral tone and accurate, natural decay which prevents this earphone from sounding sterile or flat. The C’s low end is dynamic and extended. It may surprise some listeners expecting a warm, mid-bassy sound, especially coming from Periodic’s cheaper earphones; the low-end on this earphone is simply darn clean.


Mids –

Though the low-end is delightful, the midrange of the C will be a bit more polarising, with vocals sounding a touch off to my ears. In fairness, the midrange is very revealing, its timbre isn’t metallic nor do vocals sound plain wonky. Vocals also maintain strong presence, sitting a shade in front of the bass. That said, they can come across as dry and thin, making the C more track sensitive than most earphones. To clarify, the C balances its sub-bass emphasis with a large centre midrange peak around 2KHz that brings vocals forwards. However, as there is little warmth or body to be derived from the low-end, the C sounds quite thin which is exacerbated by its vocal forwardness.

Contrarily, separation is terrific and there is a lot of air around each element. The midrange is well-layered and the C is partially redeemed by its top-end. By attenuating the upper-midrange and 6KHz regions that enhance density and smoothness, sharpness and sibilance are both mitigated. As such, they aren’t strident and don’t come across as overly bright, but they do also lack the delicacy and extension one might expect from this type of midrange signature. Granted, I am more sensitive to the minutiae of the midrange than most. However, while the C suits those wanting hyper-separated vocals with great cleanliness, the thinness of its midrange may hamper widespread appeal. I would have preferred a slightly more laid-back midrange in exchange for a more natural timbre.


Highs –

In accordance with their L-shape signature, treble is the least present frequency range, effectively smoothing off their signature and aiding listenability during longer usage. There is indeed a small 5KHz peak as indicated by Periodic’s provided frequency response graph. It isn’t emphasized to a large degree, sitting behind the other two core frequency ranges in prominence. As the 6KHz region has been attenuated, treble lacks hard-edged attack one might get from a balanced armature earphone, rather sounding slightly smooth with enhanced note body. Accordingly, there is good amount of texture and accurate shimmer and decay to treble instrumentation.

A small bump in the middle-treble grants a touch more headroom amongst an otherwise clean and black background. The net result of this signature provides great foreground/background separation and contrast which seems to be a theme of this earphone’s sound. There isn’t much extension into the upper-treble with no sparkle and little micro-detail retrieval, but there is certainly great density of detail in the foreground. Despite this, resolution is also quite good and there is enough background detail to create a convincing sense of distance and space. The high-end is non-fatiguing yet well-detailed with pleasing dimension, a good combination.


Soundstage –

As extension is limited, so too is the soundstage which extends just beyond the periphery of the head. Depth is very intimate on behalf of its forward vocals. Meanwhile, imaging is somewhat wonky, tending to push vocals to the side. Nonetheless, directional cues are sharp and the presentation is very well-layered. They aren’t pinpoint accurate but provide an involving listen. Separation is standout, very high throughout with excellent midrange layering, and an exemplary low-end performance on behalf of the C’s sensational driver control and cleanliness.


Periodic Be

Periodic Be

Tonality –

The Be features a V-shaped signature with more prominent bass and treble than the C but also a less present midrange. Bass, in particular, stands out for its large sub and mid-bass emphasis before sloping into a recessed lower-midrange. The midrange itself is natural with an accurate timbre if laid-back on behalf of their large bass emphasis. A light warmth permeates throughout alongside accurate body and articulation. Lower-treble has slight emphasis but as sibilance region is attenuated, it has a delightful smoothness while retaining a nice amount of air.

I’m not usually a fan of mods, most of them add some sort of acoustic resistance to the port which I find to hamper resolution and extension, others just sound plain odd. However, the Be is a popular earphone to mod as it assumes such a simple design with easily adjustable variables. I will detail some of the effects of the mod below alongside comparisons to stock. As I preferred the modded Be to some degree and it is both easy and reversible for all users, most comments below will be with the mod installed. Credit where credit is due, see Crinacle’s full breakdown here.


Bass –

Driver quality is also excellent on the Be and its signature is certainly more orthodox dynamic driver. Extension is terrific with physical slam and rumble alongside large emphasis giving their sound great boldness and power. The mid-bass also sees large emphasis, deriving large, warm and full bass notes. Meanwhile, the upper-bass is less present which contributes to a cleaner midrange and tone overall.

Driver control is outstanding, effectively mitigating any smearing of fine details. Decay is natural however, due to the sheer amount of bass emphasis here, there is noticeable bloat which means though the driver is resolving, some details are overshadowed. Otherwise, mid-bass is big yet defined and this is a textured and dynamic low-end for sure. Bass heads will love the Be, yet those wanting a bit more balance will want to look into the mod below.


Bass (tape mod) –

Periodic Be Mod

Covering the rear vent with a strip of cellophane tape works wonders for overall balance while a lot of the same driver quality is maintained. Bass is considerably attenuated and becomes impressively linear. Sub and mid-bass are most attenuated, bringing them more inline with the midrange. One caveat is that sub does become quite blunted, sacrificing solidity and power at the very bottom in return for greater balance. Conversely, basically all of the Be’s bloat is cleaned up while the decay and control of the driver is retained. The result is a punchy, very well-detailed low-end with a light, natural warmth and excellent definition through the mid-bass.


Mids –

In its stock form, vocals are laid-back but with the mod, occupy balanced presence. There is good separation from the bass and minimal spill with a dip in the upper-bass and lower-midrange. Vocals have an alluring presentation, with good presence and a wonderful combination of natural tone and body. This is achieved by a natural climb to a 3KHz hump alongside a light warmth that permeates from the low-end. As there is a touch of upper-midrange attenuation, the effects of its lower-midrange dip aren’t felt due to an increase in density and smoothness. Furthermore, this signature mitigates the effects of its emphasized lower-treble, with the Be showcasing accurate articulation and a total lack of rasp. There isn’t any veil up top or chestiness down-low, this is simply a well-executed midrange, especially when the bass has been brought in line. As far as reviews go, the less said is often the better and this is exemplified here with the Be simply being a terrific performer.


Highs –

The top-end is actually very similar to the C, with a modest 5KHz emphasis alongside a small bump in the middle-treble for air and headroom. Also similar to that model, there is a 6KHz dip that takes the hard edge off instrument attack, granting treble instrumentation an organic sense of body and warmth. There’s a nice amount of texture and great detail retrieval within the foreground. The Be sounds a touch smoother within the foreground to me, it also doesn’t offer quite the same level of extension and resolution as the C. As such, the Be doesn’t have as much air, but it does uphold a similarly clean and black background while also crafting a pleasing sense of air, distance and dimension. Transients are swift and well-realised, and treble is altogether a touch crisper than neutral but well-balanced and natural overall due to that enhanced note body.


Soundstage –

The Be’s soundstage isn’t the largest either, but extends nicely just beyond the head in width. I hear a little more depth from the Be, granting it a more rounded presentation. The Be’s imaging is more accurate due to its greater linearity, especially through the midrange. It is well-organised with defined layers, strongly centred vocals and precise instrument location. Separation is strong throughout, not hyper-separated like the C, but more coherent overall.


Driveability –


The Periodic C has a standard 32ohm impedance and a low 98dB sensitivity while the Be is a touch more sensitive at 100dB with an identical 32ohm impedance. Both are a far cry from the efficiency demonstrated by most earphones in this price range that start to adopt BA or hybrid configurations. That said, though both require a bit more power to reach higher listening volumes and rein in bass control, they are also forgiving on other aspects of the source, being impervious to output impedance and resistant to background hiss. Both still sound just fine out of a smartphone or portable source, however, they do scale well with a bit more power from a dedicated source. Comparing between my Khadas Tone Board + JDS Atom reference setup and the Shanling UP2 for instance, revealed a more controlled, spacious and detailed sound from the desktop setup. That said, these are surely among the more source agnostic in-ears I’ve tested.


Comparisons –

Periodic C vs Be ($299): The Be is a more typical dynamic driver sound with warmer voicing and enhanced mid-bass. The Be has more bass emphasis throughout, especially through the mid-bass which makes it warmer and fuller but also a bit tubbier sounding than the C. It also showcases strong extension and driver control, however, isn’t as clean or defined as the more balanced C with noticeably more mid-bass bloat. Mids are actually more natural on the Be, with more linear rise to 3KHz prominence and greater low-end warmth to balance out its recessed lower-midrange. Its midrange is warmer and fuller but similarly quite clear and devoid of muddiness. Meanwhile, the C’ vocal presence has better balance with its bass but it is thinner and off-timbre. The C has better separation that said. Up top, both feature 5Khz emphasis. The top end of the Be is smoother and less extended. The C has more crunch and detail presence in addition to more air and headroom. It has a slightly larger stage and more precise imaging.

Periodic C vs Be (Mod): If you’ve spent time on SBAF, you may have seen a popular mod for the Be which involves sealing the rear vent, carefully restricting the front vent and adding some extra impedance to the nozzle. This effectively attenuates the mid-bass in addition to flattening out their 5KHz peak to some degree. As I personally found the Be’s treble pleasing, I was content with covering the rear vent. Bass is attenuated by a fair degree, producing a more balanced sound. Sub-bass extension is a touch reduced but bass is more linear than the C and the mid-bass bloat is essentially gone. Control is higher on the C so it is more defined while the Be is more natural and smoother. The same can be said for the midrange, the Be retains a natural, well-bodied presentation with an excellent timbre. Meanwhile, the C is more separated but also thinner and less natural. The modded Be has a smoother treble, it has less air but also a more composed lower-treble where the C is crisper and more aggressive. The C has a larger stage and more separation while the modded Be is more coherent with a stronger centre image. I am very fond of the modded Be, it sounds very natural and balanced while retaining excellent driver quality. The C represents a step up technically and the sculpting of its signature highlights its superior driver quality, however, it isn’t as natural or composed and, therefore, suits different listeners.


Periodic Be (Mod) vs Acoustune HS1503AL ($399): A similarly priced dynamic IEM from Japan with a more V-shaped sound. The HS1503AL has substantially more bass emphasis, especially within the sub and mid-bass, more resembling the stock Be in body and fullness. Resultantly, the Be is cleaner and more linear where the HA1503AL is warmer with bolder notes. The Be has slightly more driver control where the HS1503AL is defined but isn’t quite as tight. Both have a recessed lower-midrange, as such, however, the HS1503AL is more evidently thin in terms of vocal body and is more laid-back. That said, the HS1503AL has more warmth due to its low-end tuning. Both possess upper-midrange emphasis, the HS1503AL having a glossier presentation with better extension and more clarity, the Be being flatter, smoother and more natural. The highs are also more present on the HS1503AL, especially the lower-treble. The Acoustune has a touch more instrument body due to its more linear transition from the upper-midrange. It is a lot more aggressive in its detail presentation where the C is smoother and cleaner. The HS1503AL has a larger soundstage while the Be is more layered and separated.

Periodic C vs Campfire Audio Atlas ($899): The Atlas carries a similar style of driver with Campfire’s amorphous diamond-like diaphragm. It has substantially more bass emphasis, most notably through the mid and upper-bass, creating a much fuller, bolder sound. The C is more neutrally tone where the Atlas is warm and thunderous. Both have excellent driver control, however, the C’s signature is simply much cleaner, permitting greater definition. Both have a recessed lower-midrange and thinner vocal body. The Atlas has a lot more warmth and more body permeating from its low-end, however, so its vocals sound more natural. It has a small centre midrange bump and a more gradual emphasis into the upper-midrange, granting it a bit more clarity and a more natural timbre. The C is slightly more balanced where the Atlas is slightly laid-back. Where the C is very clean, the Atlas can sound a bit chesty due to its very bold bass, it has a more powerful sound. The Atlas has a more aggressive, forward lower-treble with more attack and a touch more instrument body. Its background is similarly quite clean, but there is more extension and sparkle on the Atlas. As such, it also has a considerably larger soundstage. Incidentally, the C’s more neutral tone and note body pays off here, with superior layering and separation where the Atlas’ huge notes can occasionally obscure small details even if they are more abundant.


Verdict –

There we have the Periodic Audio Be and C, a very sound introduction for me to the tremendous quality the company is able to achieve. First, let’s discuss these drivers; both of which are stunning in quality, showcasing what quality in-house engineering can achieve. High-quality drivers permit these earphones to rein in every bass detail with perfect precision while heightening separation with lightning-fast transients. Similarly, I was impressed by their housing quality. Polycarbonate is nothing to scoff at and surely those who remember the age of polycarbonate smartphones can attest to their durability from drops and scuffs compared to glass and metal competitors, it’s tough stuff.


Which brings me to my criticisms. The cable is thin and fixed on both, identical to that included on the $100 Mg. There are plenty of high quality lightweight removable cables on the market such as the Linum BaX that would have made more appropriate company to a higher-priced earphone. Additionally, with regards to the C, the midrange is unorthodox and honestly kind of strange. Where most similarly tuned earphones at least implement some sort of low-end emphasis. Here, there is no warmth or body to bolster their forwardness. As such, the timbre is skewed.


The Be turns this on its head with fairly prevalent mid-bass bloat miring an otherwise natural signature. Fortunately, the simple design of these earphones makes them very easy to modify giving the user the ability to take the tuning process into their own hands. Here, the Be represents sensational value. As these mods can only attenuate either bass or treble with little effect on the midrange, you’d have to be sure that the C’s signature is for you. If you’re looking for a highly separated earphone with excellent layering and truly outstanding bass, the C brings excellent performance at a modest price. However, I feel the Be will find wider appeal with its more orthodox signature and driver quality that is similarly quite outstanding, especially at its lower asking price. I’ll be placing the Be on my wall of fame for its combination of excellent dynamic driver quality and, when modded, terrific balance from bottom to top.

The Periodic Audio Be and C can be purchased from Hifiheadphones for £299 and £399 respectively at the time of review. I am not affiliated with Hifiheadphones or Periodic Audio and receive no earnings from purchases through this link.


Track List –

Beck – Mellow Gold

Blur – The Magic Whip

Crush – Digital Lover

Fleetwood Mac – Greatest Hits

HEIZE, Dean, DJ Friz – And July

Jeff Bernat – She Loves Me Not

Jimmy Hendrix – Axis: Bold As Love

Joji – Sanctuary

Modest House – Good News For People Who Love Bad News

NIKI – Zephyr

Punch – Yesterday

Radiohead – Pablo Honey

Rex Orange County – Sunflower

Rich Brian – The Sailor

TALA – boy

The Cranberries – No Need To Argue

The Rolling Stones – Sticky Fingers

4 thoughts on “Periodic Audio C & Be Review – Contrast Leave a comment

  1. Awesome review – thank you! A few things to flesh out what’s going on…

    We don’t actually tune anything! We designed the best, theoretically “perfect” (well, what WE consider perfect) IEM body and housing designed for a 10mm transducer.

    Then we designed the best 10mm transducer we could, focusing on eliminating the sources of distortion and coloration: BL, Cms, and Le nonlinearities and nonlinear acoustic damping of the front and rear of the diaphragm. And this included making the impedance as flat as possible in the IEM body, so we’re about as source-agnostic as possible (as you noticed).

    Then we started playing…

    Rather than “tune” a transducer/body, we simply chose to replace the metal on the diaphragm. That’s it. No changes, no tweaking, nothing. Just the metal only. And that allows you also to hear the impact of what different metals do to the sound – when everything else is completely the same.

    It becomes more of an exploration of material properties, and allows a person to REALLY get a feel for what happens when you roll materials. There’s really no tuning going on – just a well-designed IEM body (designed and tooled in-house), a well-designed 10mm dynamic (also designed and tooled in-house), and then different materials for the diaphragm. We build everything ourselves right in Ventura, CA – and there is zero change in process, and 98% of the parts – between one IEM and another.

    Anyway, thanks for the great feedback and honest opinion! Believe it or not, we take it ALL to heart and consideration as we continue to learn more about the impressions a given design has on various people.

    One last thing, about sensitivity. Note that in the EU, there is a thing called EN50332. it states that you cannot have a passive headphone (over, on, or in-ear) that generates more than 100 dB SPL @ 1mW delivered. For a 32 Ohm speaker, that’s 179 mV RMS. So we design to that. Most vendors aren’t even aware of this legal restriction, let alone follow it. But as hard-core, long-time engineers in the audio (and headphone) world, we’re aware of compliance requirements and adhere to them.


    • Hi Dan,

      I hope you’re doing well and staying safe!

      I’d like to extend a warm thank you for your detailed feedback on my review and I’m glad you found the article informative. I appreciate the insight into what goes on at Periodic Audio and think this comment will also be a valuable resource for our readers.

      The facts in the article have been updated to reflect what you’ve said here; as this review will be posted on multiple websites, I’d like to propagate honest information. Of course, the sound evaluation will remain unchanged.

      Thank you,


      • Totally get it! We like honest, unvarnished feedback and really appreciate your comments. And we wanted to let folks know about our approach – we’re not “tuning” for a curve, we have a theoretical target for a “perfect” unit, but let the different diaphragm materials speak for themselves…:)

        Liked by 1 person

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