Short answer: the DUNU DK4001, though neither ranks well in its class. It ranks #401 of 450 in-ear headphones by sound quality, rated 2.9/5, at $899; the Fidue A91 Sirius ranks #423, rated 2.3/5, and costs $899.99, so there is little reason to consider the other one. Both are rated below 3.0/5 among the 450 in-ear headphones, and the ThieAudio Monarch MKIII, ranked #1 at $999, is a better place to start if sound quality matters.
The DUNU DK4001 is the better-sounding pick. Its hybrid design pairs a 13mm dynamic driver with four balanced armatures, and at 112 dB sensitivity and 32 ohms it plays loud from a phone. The catch: Presence is about 8.1 dB under target and air about 7.7 dB under, with a 12 dB hole near 11.9 kHz, so vocals sound distant and cymbals lose shimmer.
The case for the Fidue A91 Sirius: A hybrid of one dynamic driver and four balanced armatures per side offers a multi-driver layout for listeners who want one. The tradeoff: A preference score of 53 in crinacle’s measurement places its tuning far from what most listeners prefer.
Buy the DUNU DK4001. It is rated higher for sound quality than the Fidue A91 Sirius and costs less, which makes it the one to get unless you need something the other one does better.
Want more options? Browse the full Headphones rankings.
Specifications Side By Side
| DUNU DK4001 | Fidue A91 Sirius | |
|---|---|---|
| Price | $899.00 | $899.99 |
| Ranked | #401 of 450 in In-Ear Headphones | #423 of 450 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 60 (measured by HypetheSonics, via AutoEQ) | 53 (measured by crinacle, via AutoEQ) |
| Deviation From Target | 3.52 dB standard deviation | 4.06 dB standard deviation |
| Tonal Tilt | +0.16 (negative is warmer, positive brighter) | +0.13 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-5.1 dB at 30 Hz) | - |
| Connection | Wired | Wired |
| Driver Type | Hybrid (1 dynamic + 4 balanced armature) | Hybrid (1 dynamic + 4 balanced armature) |
| Drivers | 1 x 13mm dynamic + 4 x balanced armature | 1 x dynamic + 4 x balanced armature |
| Impedance | 32 ohms | 20 ohms |
| Sensitivity | 112 dB | 113 dB |
| Frequency Response | 5Hz - 40kHz (Manufacturer specified) | 4Hz - 45kHz (Manufacturer specified) |
| Built-in Microphone | No | No |
Related Headphone Comparisons
How DUNU DK4001 compares with other leading options:
- FiiO FH5 vs DUNU DK4001
- InEar StageDiver SD5 vs DUNU DK4001
- Audio-Technica ATH-CK2000Ti vs DUNU DK4001
- Fidue A91 Sirius vs FiiO FA7S
- Audio-Technica ATH-IEX1 vs Fidue A91 Sirius
Prices on this page were last checked October 11, 2026 at 4:59 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.
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The Two Headphones In Full
DUNU DK4001: $899.00 HiFiGo eBay
Pros: Its hybrid design pairs a 13mm dynamic driver with four balanced armatures, and at 112 dB sensitivity and 32 ohms it plays loud from a phone. HypetheSonics’ measurement shows its best match is a warm, bass leaning taste, and its rating equals the Audio-Technica ATH-CK2000Ti. A preference score of 60 leaves plenty of room for listeners willing to apply EQ.
Cons: Presence is about 8.1 dB under target and air about 7.7 dB under, with a 12 dB hole near 11.9 kHz, so vocals sound distant and cymbals lose shimmer. A 6.1 dB peak near 7.7 kHz on top of that uneven treble, 3.52 dB of deviation overall, adds edginess to sibilants. Sub-bass sits about 5.2 dB low, and it rates below the Fatfreq Reference Pro SE and InEar StageDiver SD5.
Full DUNU DK4001 review and specifications →
| Released | 2019 (7 years ago) |
|---|---|
| Back | Closed |
| Built-in Microphone | No |
| Connection | Wired |
| Deviation From Target | 3.52 dB standard deviation |
| Driver Type | Hybrid (1 dynamic + 4 balanced armature) |
| Drivers | 1 x 13mm dynamic + 4 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 5Hz - 40kHz (Manufacturer specified) |
| Harman Preference Score | 60 (measured by HypetheSonics, via AutoEQ) |
| Impedance | 32 ohms |
| Sensitivity | 112 dB |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-5.1 dB at 30 Hz) |
| Tonal Tilt | +0.16 (negative is warmer, positive brighter) |
EQ preset to match the Harman 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 AutoEQ from its measured frequency response.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +2.4 dB | 0.70 |
| Peak | 5,069 Hz | +19.7 dB | 0.43 |
| Peak | 6,458 Hz | -20.0 dB | 1.04 |
| Peak | 1,949 Hz | -18.2 dB | 0.73 |
| Peak | 2,310 Hz | +12.4 dB | 1.07 |
| High shelf | 10,000 Hz | -4.6 dB | 0.70 |
| Peak | 176 Hz | -1.6 dB | 1.09 |
| Peak | 9,726 Hz | +3.0 dB | 3.09 |
| Peak | 705 Hz | +0.9 dB | 1.20 |
| Peak | 1,405 Hz | -1.0 dB | 3.61 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Fidue A91 Sirius: $899.99 Amazon eBay
Pros: A hybrid of one dynamic driver and four balanced armatures per side offers a multi-driver layout for listeners who want one. Its rating sits above the FiiO FA7S, which costs slightly more. No amp is needed, since the 113 dB sensitivity gives plenty of volume from a phone.
Cons: A preference score of 53 in crinacle’s measurement places its tuning far from what most listeners prefer. The Kinera Skuld and Audio-Technica ATH-CK2000Ti are both rated higher and cost noticeably less, and there is no microphone for calls.
Full Fidue A91 Sirius review and specifications →
| Released | Jun 2016 (10 years ago) |
|---|---|
| Back | Closed |
| Built-in Microphone | No |
| Connection | Wired |
| Deviation From Target | 4.06 dB standard deviation |
| Driver Type | Hybrid (1 dynamic + 4 balanced armature) |
| Drivers | 1 x dynamic + 4 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 4Hz - 45kHz (Manufacturer specified) |
| Harman Preference Score | 53 (measured by crinacle, via AutoEQ) |
| Impedance | 20 ohms |
| Sensitivity | 113 dB |
| Tonal Tilt | +0.13 (negative is warmer, positive brighter) |
EQ preset to match the Harman target
Set a preamp of -7.3 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by AutoEQ from its measured frequency response.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +5.5 dB | 0.70 |
| Peak | 9,827 Hz | +5.4 dB | 1.70 |
| Peak | 168 Hz | -4.0 dB | 0.65 |
| Peak | 4,982 Hz | +5.4 dB | 1.22 |
| Peak | 1,608 Hz | -6.0 dB | 3.14 |
| High shelf | 10,000 Hz | +4.6 dB | 0.70 |
| Peak | 859 Hz | +3.0 dB | 1.73 |
| Peak | 331 Hz | -1.0 dB | 1.86 |
| Peak | 1,257 Hz | -2.3 dB | 3.72 |
| Peak | 9,483 Hz | -2.7 dB | 4.60 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons