Astell & Kern AK Zero 1 Review

Over the years Astell & Kern has collaborated with IEM manufacturers like JH Audio and Campfire Audio, but have never fully released an A&K branded earphone. Only recently have A&K broken out of exclusively making DAPs, like the PEE51 DAC adapter that was released earlier this year. Now we have the A&K Zero 1, their first true IEM, and I’m excited to hear what it has in store.

A&K items

What You Get

  • AK ZERO1 Earphones L/R x 1
  • 3.5mm MMCX Cable x 1
  • 5 Pairs of Silicone Ear tips
  • 1 Pair of Foam Tips
  • Carrying Case x 1

A&K Size

Look and Feel

In terms of build, A&K serves up its own unique aesthetic that immediately stands out from other IEMs in various price ranges. It shares a similarly rigid design with some of their DAPs, which already gives A&K as IEM brand an identifiable look. Its angular housing is surprisingly larger than I had expected, but with a smaller spout for an easier insertion to the ear. You can still feel them for a bit, but after a while, it doesn’t become too distracting, and the support it has is one of the biggest proponents of its comfortability.

A&K Cable


The Zero 1 is a hybrid system featuring dual custom balanced armature drivers and a 5.6mm dynamic unit. However, this dynamic driver also has planar magnetic properties, which in a way is a pretty big innovation that kind of gets swept under the rug when talking about the Zero 1. Each driver parameter is sent through a crossover network positioning the units in enclosed acoustic chambers.

A&K Front


Other A&K collaborations have succeeded in the past, but now it’s time for them to really showcase their abilities with their first branded IEM. Excited to check them out, I immediately started listening to a few good tracks to get a good sense of how its soundstage operates, and the results were a bit less ideal than I would have hoped. Its width can span broadly to immerse you well enough in the sound, but the imaging is brought in a bit tighter aside from elements panned to the extreme left and right position. It’s a more spatially linear soundstage than I was expecting, and while the placement of sounds themselves was clearly displayed, they lacked spatial depth. Some of the layering separates the instruments and effects well for forward and back dimension but mostly appeared on a surface level that had music appear right in front of my face rather than around me.

Low End

When it comes to the bass, these are definitely a darker sounding IEM than I thought it would be. After listening to the Zero 1 for quite a while, I found this timbre to be picky. Tracks that aren’t so low-end focused will find a strong mid-bass that’s well-controlled but is tuned in a way to stand out the most within the sound signature. There’s a consistent smooth tone to it, but it doesn’t sound natural for some tracks. For instance, a song like “Fade Into You” by Mazzy Star performs great with its more textured instrumentals that focus more on coloration than clarity. It’s also supported by a good helping of sub-bass vibration to give the timbre a more engrossing kick. I definitely preferred more Shoegaze and Goth-Pop with the Zero 1 than I did in other genres like Metal and even some Electronic with this low-end.


In the midrange, things start to get a bit foggy. This is due to the semi-recession that’s going on with some of the frequency bands. It gives the sound signature its darker timbre but sacrifices some clarity within the fundamental and upper-midrange frequencies. Vocals have good texture but lack some detail that would really help with the definition of these frequencies. Sometimes it can make acoustic guitars appear hollow, but the response is actually still full in its appearance. Too much resonance from the low-mids hamper some of the resolution, but the mids still feel complete in their tonality with the exception of some notches.


For a darker IEM, there’s definitely a significant presence of treble. The tone of the response can have a nice shine to it, and although it can span into some bright territory, the frequencies are never piercing. Cymbals have a nice splash, but other instrumentals don’t receive the same accentuation. Details are sparse but still have some resonance to enjoy. While it isn’t always the response you need, there isn’t a lot of recession to note.


Not everything sticks the landing with the Astell & Kern Zero 1 in the sound department, but if it wasn’t for the $699 price point I might recommend this IEM. However, the price is just too competitive for me to get behind the Zero 1. It’s an admirable first attempt from Astell and Kern, but ultimately just doesn’t possess a sound I can really sink my teeth into.

Pros  Cons
  • Unique build 
  • Fine fit
  • Innovative dynamic/planar driver
  • Good cable
  • Ample sub-bass
  • Picky soundstage
  • Cloudy midrange
  • Bright treble

The Astell & Kern AK Zero 1 is available at Audio46.

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Alex S. is a sound designer and voice-over artist who has worked in film, commercials, and podcasts. He loves horror movies and emo music.