Short answer: the HiBy Crystal 6. It ranks #390 of 450 in-ear headphones by sound quality, rated 3.0/5, at $459; the FiiO FA9 ranks #403, rated 2.8/5, and costs $499.99, so there is little reason to consider the other one.
What the HiBy Crystal 6 does well: A lively V-shaped tuning with about 3.7 dB of extra bass and a treble lift of 5 to 6 dB above 6 kHz, which gives drums punch and cymbals plenty of sparkle. The catch: Squig.link measurements show a 9.9 dB peak near 7.9 kHz, so sibilance and hi-hats can turn sharp and fatiguing at higher volumes.
Why pick the FiiO FA9: Six balanced armatures per side and sensitivity of 110 to 113 dB/mW make it easy to drive from a phone, with an impedance switch between 16 and 32 ohms to tune the match with a source. The tradeoff: oratory1990’s measurement shows presence averaging 6.8 dB below target with a 9.6 dB dip near 3.4 kHz, so vocals and lead instruments sound pushed back and lack clarity.
Buy the HiBy Crystal 6. It is rated higher for sound quality than the FiiO FA9 and costs less, so it is the default pick unless a specific strength of the other one matters more to you.
Looking for alternatives? See the complete Headphones rankings.
Specifications Side By Side
| HiBy Crystal 6 | FiiO FA9 | |
|---|---|---|
| Price | $459.00 | $499.99 |
| Ranked | #390 of 450 in In-Ear Headphones | #403 of 450 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 62 (measured by crinacle, via AutoEQ) | 59 (measured by oratory1990, via AutoEQ) |
| Deviation From Target | 3.17 dB standard deviation | 3.22 dB standard deviation |
| Tonal Tilt | +0.21 (negative is warmer, positive brighter) | -0.61 (negative is warmer, positive brighter) |
| Connection | Wired | Wired |
| Driver Type | Balanced armature | Balanced armature |
| Drivers | 6 x balanced armature | 6 x balanced armature |
| Impedance | 14 ohms | 16 ohms (switchable to 32 ohms) |
| Sensitivity | 107 dB/mW | 110/113 dB/mW |
| Frequency Response | 5Hz - 60kHz (Manufacturer specified) | 15Hz - 40kHz (Manufacturer specified) |
| Built-in Microphone | No | - |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-5.0 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-4.8 dB at 30 Hz) |
| Weight | - | 0 lbs (6.2 g) per earpiece |
Related Headphone Comparisons
More top alternatives to HiBy Crystal 6:
- HiBy Crystal 6 vs Yanyin Mahina
- HiBy Crystal 6 vs Shanling ME700
- Cayin Fantasy vs HiBy Crystal 6
- FiiO FA9 vs Shure SE535
- FiiO FA9 vs Jabra Evolve 75e
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
HiBy Crystal 6: $459.00 HiFiGo eBay
Pros: A lively V-shaped tuning with about 3.7 dB of extra bass and a treble lift of 5 to 6 dB above 6 kHz, which gives drums punch and cymbals plenty of sparkle. Sub-bass stays within 6 dB of target down to 20 Hz. Six balanced armatures at 14 ohms and 107 dB/mW run fine from a phone. It matches the rating of the Shanling ME700 for less money.
Cons: Squig.link measurements show a 9.9 dB peak near 7.9 kHz, so sibilance and hi-hats can turn sharp and fatiguing at higher volumes. A 3.7 dB lift from 200 Hz to 1 kHz thickens male vocals and lower instruments. The Etymotic ER4XR earns the same rating for considerably less.
Full HiBy Crystal 6 review and specifications →
| Released | Mar 2021 (5 years ago) |
|---|---|
| Back | Closed |
| Built-in Microphone | No |
| Connection | Wired |
| Deviation From Target | 3.17 dB standard deviation |
| Driver Type | Balanced armature |
| Drivers | 6 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 5Hz - 60kHz (Manufacturer specified) |
| Harman Preference Score | 62 (measured by crinacle, via AutoEQ) |
| Impedance | 14 ohms |
| Sensitivity | 107 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-5.0 dB at 30 Hz) |
| Tonal Tilt | +0.21 (negative is warmer, positive brighter) |
EQ preset to match the Harman target
Set a preamp of -4.5 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 | +5.0 dB | 0.70 |
| Peak | 173 Hz | -3.8 dB | 0.30 |
| Peak | 1,805 Hz | +2.9 dB | 2.77 |
| Peak | 6,231 Hz | -6.6 dB | 5.99 |
| Peak | 945 Hz | +4.5 dB | 0.93 |
| High shelf | 10,000 Hz | +0.4 dB | 0.70 |
| Peak | 4,649 Hz | +2.8 dB | 5.98 |
| Peak | 2,604 Hz | -1.7 dB | 6.00 |
| Peak | 5,438 Hz | -1.5 dB | 6.00 |
| Peak | 36 Hz | -0.2 dB | 1.94 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
FiiO FA9: $499.99 Amazon eBay
Pros: Six balanced armatures per side and sensitivity of 110 to 113 dB/mW make it easy to drive from a phone, with an impedance switch between 16 and 32 ohms to tune the match with a source. Each earpiece weighs just 6.2 g. Bass and low mids sit at or slightly above target, which suits listeners who like a warm, smooth balance, and it is rated above the pricier Kinera Skuld.
Cons: oratory1990’s measurement shows presence averaging 6.8 dB below target with a 9.6 dB dip near 3.4 kHz, so vocals and lead instruments sound pushed back and lack clarity. Sub-bass runs about 3.7 dB under target, so electronic music has less low rumble than the specs suggest.
Full FiiO FA9 review and specifications →
| Released | 2020 (6 years ago) |
|---|---|
| Back | Closed |
| Connection | Wired |
| Deviation From Target | 3.22 dB standard deviation |
| Driver Type | Balanced armature |
| Drivers | 6 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 15Hz - 40kHz (Manufacturer specified) |
| Harman Preference Score | 59 (measured by oratory1990, via AutoEQ) |
| Impedance | 16 ohms (switchable to 32 ohms) |
| Sensitivity | 110/113 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-4.8 dB at 30 Hz) |
| Tonal Tilt | -0.61 (negative is warmer, positive brighter) |
| Weight | 0 lbs (6.2 g) per earpiece |
EQ preset to match the Harman target
Set a preamp of -5.6 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 | +2.1 dB | 0.70 |
| Peak | 182 Hz | -3.9 dB | 0.55 |
| Peak | 2,946 Hz | +5.3 dB | 1.88 |
| Peak | 1,302 Hz | -2.0 dB | 1.48 |
| Peak | 7,001 Hz | +2.9 dB | 0.83 |
| High shelf | 10,000 Hz | -2.7 dB | 0.70 |
| Peak | 8,655 Hz | +1.3 dB | 2.14 |
| Peak | 4,276 Hz | -2.3 dB | 6.00 |
| Peak | 5,231 Hz | +3.0 dB | 5.93 |
| Peak | 6,241 Hz | -1.8 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons