Review: Zero Audio Carbo i – Something of a marvel

Disclaimer: I purchased the Zero Audio Carbo i for the purposes of this review. I purchased it from e-Earphone in Tokyo. Carbo i goes for around 45$ USD. You can find out all about it here: Zero Audio Carbo i.

I met an opera singer, composer, and multi-instrumentalist on the airplane back from Canada. Yep, Canada for Christmas and New Years. Freezing! One morning was minus twenty seven. The day we arrived it was minus seven. Minus seven is child’s play- but I was pretty much a child when I left Canada for Tokyo, where a cold day is plus four. In Toronto, the opera guy had wrapped himself in a duffle bag. He’s from Argentina.

In Argentina, like in Canada, finding a good selection of earphones is tough stuff. And there are like no vendors. Tokyo was like geek heaven for him. It’s become that for me. Naturally, we headed to e-Earphone, browsed a bunch of earphones, mostly from local companies. He picked up Carbo Basso. I picked up Carbo i, Zero Audio’s most recent ‘slant in’ fit phones.

Not sound

They don’t fit exactly like Etymotic’s ER4 series, but their foolproof one-handed go-in, easy, evince what best I liked about Etymotic earphones. They’re something of a departure from some of the economical, traditional-fit earphones Zero have produced in the last decade.

One, they’re driven by a tiny dynamic micro driver (more on this in the sound section). Two, they go in like nails. The first really can work well- when everything lines up. The latter makes inserting and removing them easy as pie. They keep enough body out of the ear that you’ll never accidentally grab the cable when taking them out. They‘re also super light, and even when pressed hard between destructive fingers, won’t flex. The carbon fibre muffler is decorative. What gives them strength is their precision extruded aluminium body.

Speaking of, Carbo i is a 45$ earphone. And it’s machined way, way above its asking price. Here are some quick points:

Point 1: the rubber sheath out of which the cable juts is tough, really firm fitting, and almost perfectly flush with the body. Point 2: both the flange and preceding metallic edges are finely chamfered and comfy even when roughly handled. Point 3: the cable is luxury. Point 4: its plug is solid, slim, and well branded. Finally, the grill’s fine nylon mesh shows no signs of glue, and is well centred. Every point embarrasses a number of earphones whose market values extend well above 1000$.

The cable is something of a marvel. It pliable, strong, and nearly free of microphonic noise. It’s a bit shiny, but not in that cheapo Air Canada International Flight pack-in sort of way. Carbo i’s neck cinch stays tight, and adjusting it sends only the slightest touch noise to the ears. At its butt is a really low-profile L-shape plug that fits deep smartphone cases perfectly. Engraved into its outer face is the Zero Audio logo. Ditto the blocky y-split. And the cinch labels the cables to its right and left with a raised L and R, both in the Zero Audio font type. Sick.

Carbo i’s carbon fibre housing calls back to Zero Audio’s earliest, most obvious branding points. Behind it are rings, red for right, silver for left. The sound tube is fat, fiercely flanged, and grippy. Even cramming the earphones into your ears won’t send its tips off-cant. You can yank Carbo i out and all parts stay put.

Carbo i is scant on accessories. It comes with a total of three ear tips, slim, medium, and fat. There’s also a hard-fibre cotton carrying pouch, notable because it won’t shed like RHA’s MA650 / MA750’s pouch will. The tips are great for sensitive ears. How’s that? Well, they eschew an equatorial seam for a smooth taper from mouth to hem, so there’s nothing to rub oddly against the ear canal.

From stem to stern, Carbo i is superlatively designed.

Sound and more after the jump:

3.9/5 - (34 votes)

Back before he became the main photographer for bunches of audio magazines and stuff, Nathan was fiddling with pretty cool audio gear all day long at TouchMyApps. He loves Depeche Mode, trance, colonial hip-hop, and raisins. Sometimes, he gets to listening. Sometimes, he gets to shooting. Usually he's got a smile on his face. Always, he's got a whisky in his prehensile grip.


  • Reply February 7, 2018

    dale thorn

    Wow! I bought Sennheiser’s Ambeo recently and was thinking how much better it sounds than most of what I’ve listened to for the past several months, and now this – something probably close to that sound, and only $45.

    Now, where to get the Carbo i?

    • Reply February 8, 2018

      ohm image

      Well, good luck getting it, you know?

  • Reply February 7, 2018


    Hey, great review.

    I was wondering how carbo I compared to etymotic, what are their differences? Are they more similar rather than different in terms of sound signature and resolution ?

    • Reply February 7, 2018


      I’m afraid I have the Ety’s and Nathan has the Carbo. Not sure Nathan knows the Ety’s to reply

    • Reply February 8, 2018

      ohm image

      Next to Ety ER4 (long-time fan here), this one hasn’t the same peaks up top, and its bottom end has far more sound pressure. Not as good instrument separation, though.

      • Reply February 28, 2018


        How about in comparison to hifiman re0 or re-ZERO? especially about bass tightness, mids neutrality, and treble extension?

  • Reply February 12, 2018

    Rizqy Halim

    How was it compared to carbo mezzo? Soundwise

    • Reply February 12, 2018

      ohm image

      Alas I don’t have that earphone.

    • Reply October 18, 2018

      Vladimir WOZNY

      It’s definitely more on the neutral side compared to the mezzo thanks to the less boomy bass.

      It’s closer to the clasical tenore.

  • Reply June 20, 2018


    How does it sound in comparison to Zero audio carbo doppio? Would it be safe to assume carbo doppio is similar but upgraded version (detailed/bassy/etc) of carbo i?

    • Reply June 21, 2018

      ohm image

      I’m sorry but I don’t own the Doppio.

  • Reply April 24, 2019


    Without equalization, this new, shiny, more expensive ZH-DX240-CI is simply unbearable. It has a very recessed middle of the spectrum; every voice, music, and anything is painfully thin, peeping. The balance, that the Carbo Tenore was good in, has completely gone.

    But. If you take the take to carefully and over-aggressively set the equalizer in your each and every sound sources for this earphone – at last the sliders’ positions will resemble a boa constrictor with significant up and down waves -, you will be rewarded by a suprisingly big-headphone-like sound with more details, surely beyond the Carbo Tenore’s capabilites. I don’t know yet, how good it is, I simply have not enough time to compare them.

  • Reply April 24, 2019


    By the way, the flat cable is a double-edged sword as well. It is really easier to handle (the color coding is nice), but also has a higher mechanical force to loose the cans in your ears.

    You can’t caper too much with this earphone, even a simple walking may twist and loose it in your ears, and outer world breaks in – or at least this happens to my ears.

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