Short answer: the Fidue A91 Sirius, though neither ranks well in its class. It ranks #423 of 450 in-ear headphones by sound quality, rated 2.3/5, at $899.99; the FiiO FA7S ranks #433, rated 1.9/5, and costs $947.19, which makes this an easy call rather than a real tradeoff. 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 Fidue A91 Sirius is the better-sounding pick. 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.
What the FiiO FA7S does well: Six balanced armature drivers per side at 18 ohms and 111 dB/mW make it very easy to drive from a phone or a small dongle. The tradeoff: Crinacle’s measurement yields a preference score of just 48 with a 3.7 dB spread around the target, a poor tonal result at a flagship price.
Buy the Fidue A91 Sirius. It is rated higher for sound quality than the FiiO FA7S and costs less, which makes it the one to get unless you need something the other one does better.
Still deciding? The full Headphones rankings cover every ranked option.
Specifications Side By Side
| Fidue A91 Sirius | FiiO FA7S | |
|---|---|---|
| Price | $899.99 | $947.19 |
| Ranked | #423 of 450 in In-Ear Headphones | #433 of 450 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 53 (measured by crinacle, via AutoEQ) | 48 (measured by crinacle, via AutoEQ) |
| Deviation From Target | 4.06 dB standard deviation | 3.72 dB standard deviation |
| Tonal Tilt | +0.13 (negative is warmer, positive brighter) | -0.89 (negative is warmer, positive brighter) |
| Connection | Wired | Wired |
| Driver Type | Hybrid (1 dynamic + 4 balanced armature) | Balanced armature |
| Drivers | 1 x dynamic + 4 x balanced armature | 6 x balanced armature |
| Sensitivity | 113 dB | 111 dB/mW |
| Frequency Response | 4Hz - 45kHz (Manufacturer specified) | 10Hz - 40kHz (Manufacturer specified) |
| Built-in Microphone | No | No |
| Impedance | 20 ohms | 18 ohms |
| Weight | - | 0 lbs (8.4 g) per earbud |
Related Headphone Comparisons
More top alternatives to Fidue A91 Sirius:
- DUNU DK4001 vs Fidue A91 Sirius
- Audio-Technica ATH-IEX1 vs Fidue A91 Sirius
- FiiO FA7S vs Campfire Audio Dorado 2020
- Audio-Technica ATH-IEX1 vs FiiO FA7S
- Shure SE425 vs Audio-Technica ATH-E70
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
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
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FiiO FA7S: $947.19 Amazon eBay
Pros: Six balanced armature drivers per side at 18 ohms and 111 dB/mW make it very easy to drive from a phone or a small dongle. At 8.4 g per earbud it is light for a multi-driver in-ear.
Cons: Crinacle’s measurement yields a preference score of just 48 with a 3.7 dB spread around the target, a poor tonal result at a flagship price. The Fidue A91 Sirius rates higher at a similar cost, and there is no inline microphone for calls.
Full FiiO FA7S review and specifications →
| Released | Oct 2021 (5 years ago) |
|---|---|
| Back | Closed |
| Built-in Microphone | No |
| Connection | Wired |
| Deviation From Target | 3.72 dB standard deviation |
| Driver Type | Balanced armature |
| Drivers | 6 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 10Hz - 40kHz (Manufacturer specified) |
| Harman Preference Score | 48 (measured by crinacle, via AutoEQ) |
| Impedance | 18 ohms |
| Sensitivity | 111 dB/mW |
| Tonal Tilt | -0.89 (negative is warmer, positive brighter) |
| Weight | 0 lbs (8.4 g) per earbud |
EQ preset to match the Harman target
Set a preamp of -6.5 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 | +1.6 dB | 0.70 |
| Peak | 192 Hz | -4.8 dB | 0.57 |
| Peak | 2,618 Hz | +6.2 dB | 1.61 |
| Peak | 9,159 Hz | +5.6 dB | 1.14 |
| Peak | 388 Hz | -1.1 dB | 1.47 |
| High shelf | 10,000 Hz | -0.5 dB | 0.70 |
| Peak | 4,349 Hz | -2.4 dB | 4.22 |
| Peak | 5,384 Hz | +2.5 dB | 6.00 |
| Peak | 940 Hz | +0.8 dB | 3.02 |
| Peak | 3,246 Hz | +1.3 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons