Periodic Audio is a company focused on producing IEMs (in-ear monitors) that perform at a high level for their price point. The company offers four models, all virtually identical save for the material used to create the full-range dynamic drivers. Until recently, the Periodic Audio Beryllium ($299) held the top slot in the Periodic hierarchy, but now there is the flagship Periodic Audio  Carbon ($399) . And in this case the carbon takes the form of... diamond. Other models in the company lineup are the Magnesium ($99) and Titanium ($199) .

In addition to the earphones, Periodic Audio sent me it's ultra-simple, ultraportable amplifier, the Nickel ($299) . There's practically nothing to it, and the idea is it provides 6.5 dB of transparent gain to give your phone a helping hand. It's an old-school, analog solution for listeners who like some extra oomph in their portable playback.

Features and Specifications

Periodic Audio Carbon IEM

Carbon is an IEM with lab-grown diamond drivers. The company claims to know of no other IEM with lower distortion... and fundamentally, the key to audio transparency is the absence of distortion.

The driver's diamond layer measures a mere 8 µm (microns) and are proprietary to Periodic Audio. The driver is housed in a black polycarbonate body that is all business and will draw attention to you as you walk down the street.

Rated frequency responses 12 Hz to 38 kHz and nominal impedance is 32 ohms. Sensitivity is rated as 98 dB with 1 mW of input, measured in-ear and maximum power handling is 200 mW continuous, allowing for a peak SPL of 121 dB. With 1 mW of input power, it keeps total harmonic distortion to below 0.2%, according to Periodic Audio.

The permanently attached, tangle resistant cable measures 1.5 m. A small tin is provided with replacement eartips in silicone as well as foam, and in various sizes. Also included is a quarter-inch adapter as well as an airplane adapter. These IEM's are assembled in the USA and warrantied for 5 years.

One feature of Periodic Audio is the company insistently only spends money where it matters for the sake of performance. Therefore, the packaging for its products is as minimalist as it gets. The company maintains a FAQ where it is totally transparent about its philosophy and decision-making process, including the packaging: "Simply put: YOU DON'T LISTEN TO THE BOX." I'm all for this performance-first attitude but I think it's important to alert prospective buyers that you will not have the "unboxing experience" that some other products offer.

Periodic Audio skips the fancy packaging, spends the money on engineering and materials.

Nickel Amp

50mm long, 30mm wide, 18mm thick. 20 grams. Yep, it's tiny and super light. Nickel is a polycarbonate-body "pocket amp" that charges in 30 minutes or less and provides 8 hours of amplification (6.5 dB fixed gain) with 8 Hz to 80 kHz response and