The Astell & Kern AK ZERO1 ranks #133 out of 1476 total In-Ear Headphones for sound quality. See all Headphones rankings for every top pick.
Brand: Astell & Kern
Prices on this page were last checked October 20, 2026 at 10:35 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
As an eBay Partner, we may be compensated if you make a purchase.
#133 Astell & Kern AK ZERO1: $699 Discontinued eBay
Pros: A tribrid with a 5.6 mm dynamic driver, two balanced armatures and a planar tweeter, scoring 80 as the median of four measurements. Bass and midrange stay within about 2 dB of target, and the MMCX cable is detachable.
Cons: Treble from 5 to 12 kHz sits about 2 dB low with dips of 4.4 dB near 6.3 kHz and 4.1 dB near 9.2 kHz, so cymbals sound a little soft. It is discontinued after selling for $699, and the 96 dB/mW sensitivity needs more volume than most IEMs.
Is the Astell & Kern AK ZERO1 right for you?
Buy it if
- you want the tuning most listeners prefer in blind tests out of the box (Harman score 80).
- you want sub-bass rumble that reaches down to 20 Hz.
Skip it if
- you want to buy it new: it is discontinued.
| Released | Nov 2021 (4 years ago) |
|---|---|
| Back | Closed |
| Connection | Wired |
| Deviation From Target | 1.73 dB standard deviation |
| Driver Type | Hybrid (dynamic + balanced armature + planar magnetic) |
| Drivers | 1 x 5.6mm dynamic + 2 x balanced armature + 1 x planar |
| Form Factor | In-ear |
| Frequency Response | 25Hz - 30kHz (Manufacturer specified) |
| Harman Preference Score | 80 (median of 4 squig.link measurements scored separately, calibrated to AutoEQ) |
| Impedance | 16 ohms |
| Sensitivity | 96 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-2.1 dB at 30 Hz) |
| Tonal Tilt | -0.09 (negative is warmer, positive brighter) |
EQ Presets
Harman target
Set a preamp of -3.3 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 4 independent measurements from squig.link, in the filter layout AutoEQ uses. Predicted Harman match with this EQ: 92 out of 100, up from 80.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +1.2 dB | 0.70 |
| Peak | 186 Hz | -3.3 dB | 0.77 |
| Peak | 761 Hz | +1.3 dB | 2.89 |
| Peak | 3,420 Hz | +1.8 dB | 5.02 |
| Peak | 4,795 Hz | -2.2 dB | 6.00 |
| Peak | 6,120 Hz | +3.6 dB | 6.00 |
Neutral target
Set a preamp of -3.3 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 4 independent measurements from squig.link, in the filter layout AutoEQ uses. Predicted Neutral match with this EQ: 93 out of 100, up from 50.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -7.3 dB | 0.70 |
| Peak | 186 Hz | -3.2 dB | 0.68 |
| Peak | 741 Hz | +1.3 dB | 2.42 |
| Peak | 3,418 Hz | +1.8 dB | 4.96 |
| Peak | 4,796 Hz | -2.1 dB | 6.00 |
| Peak | 6,120 Hz | +3.6 dB | 6.00 |
Studio flat target
Set a preamp of -3.3 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 4 independent measurements from squig.link, in the filter layout AutoEQ uses. Predicted Studio flat match with this EQ: 91 out of 100, up from 30.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -9.9 dB | 0.70 |
| High shelf | 10,000 Hz | +2.0 dB | 0.70 |
| Peak | 176 Hz | -5.1 dB | 0.74 |
| Peak | 2,877 Hz | +3.3 dB | 2.68 |
| Peak | 4,756 Hz | -3.7 dB | 6.00 |
| Peak | 6,706 Hz | +2.0 dB | 2.83 |
Warm target
Set a preamp of -2.5 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 4 independent measurements from squig.link, in the filter layout AutoEQ uses. Predicted Warm match with this EQ: 94 out of 100, up from 80.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +1.5 dB | 0.70 |
| High shelf | 10,000 Hz | -3.2 dB | 0.70 |
| Peak | 26 Hz | +1.0 dB | 1.61 |
| Peak | 186 Hz | -3.0 dB | 0.79 |
| Peak | 753 Hz | +1.5 dB | 2.81 |
| Peak | 2,201 Hz | -1.1 dB | 1.50 |
| Peak | 4,688 Hz | -4.2 dB | 4.84 |
| Peak | 6,021 Hz | +1.6 dB | 6.00 |
Bass target
Set a preamp of -6.2 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 4 independent measurements from squig.link, in the filter layout AutoEQ uses. Predicted Bass match with this EQ: 94 out of 100, up from 68.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +5.0 dB | 0.70 |
| Peak | 26 Hz | +1.2 dB | 1.32 |
| Peak | 186 Hz | -3.3 dB | 0.81 |
| Peak | 766 Hz | +1.3 dB | 3.07 |
| Peak | 1,466 Hz | -0.8 dB | 2.76 |
| Peak | 3,421 Hz | +1.8 dB | 5.04 |
| Peak | 4,795 Hz | -2.2 dB | 6.00 |
| Peak | 6,121 Hz | +3.6 dB | 6.00 |
| Peak | 7,456 Hz | +1.2 dB | 5.17 |
Bright target
Set a preamp of -3.4 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 4 independent measurements from squig.link, in the filter layout AutoEQ uses. Predicted Bright match with this EQ: 86 out of 100, up from 38.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -7.3 dB | 0.70 |
| High shelf | 10,000 Hz | +1.7 dB | 0.70 |
| Peak | 186 Hz | -3.3 dB | 0.66 |
| Peak | 734 Hz | +1.3 dB | 2.56 |
| Peak | 3,383 Hz | +1.9 dB | 6.00 |
| Peak | 5,673 Hz | +3.2 dB | 1.16 |
V-shaped target
Set a preamp of -5.5 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 4 independent measurements from squig.link, in the filter layout AutoEQ uses. Predicted V-shaped match with this EQ: 84 out of 100, up from 66.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +5.4 dB | 0.70 |
| High shelf | 10,000 Hz | +2.0 dB | 0.70 |
| Peak | 186 Hz | -1.9 dB | 0.90 |
| Peak | 1,391 Hz | -1.2 dB | 3.26 |
| Peak | 3,325 Hz | +1.5 dB | 6.00 |
| Peak | 5,202 Hz | +3.4 dB | 0.90 |
- Reviews, Comparisons and Sound Samples
Frequency Response
How the Astell & Kern AK ZERO1 measures across the audible range, against the Harman in-ear target that most listeners prefer in blind tests. Where the line sits above the target that range sounds louder (more bass, brighter treble), below it quieter. The curve is the median of 4 independent measurements, so one odd sample or rig cannot skew it, and both lines are shifted so their 500 Hz to 2 kHz average sits at 0 dB.
Measurement data: the median of 4 independent measurements from the squig.link databases of aftersound, ekaudio, precog and vsg. Thanks to each of them for publishing their work.