Short answer: the FiiO FD5. It ranks #335 of 450 in-ear headphones by sound quality, rated 3.7/5, at $505.28. The iBasso IT04 ranks #344, rated 3.6/5, at $499, $6.28 cheaper, which does not close the gap in sound quality.
Why pick the FiiO FD5: Crinacle’s measurement gives it a preference score of 70, and across seven hobbyist measurements on squig.link bass rises about 4 dB above target with flat sub-bass extension to 20 Hz, giving bass guitar and kick drums a full, punchy body. Watch for: The bass boost spills into the low mids by about 2 dB, which can thicken male vocals and make dense mixes sound slightly congested.
The case for the iBasso IT04: A preference score of 69 in crinacle’s measurement puts the IT04 in solid, listenable territory for an in-ear. Watch for: A score of 69 trails the best in-ears, so the tuning is noticeably off the Harman target in places.
Buy the FiiO FD5. It is rated higher for sound quality, and the $6.28 saving on the iBasso IT04 is not enough to make up the difference.
Still deciding? The full Headphones rankings cover every ranked option.
Specifications Side By Side
| FiiO FD5 | iBasso IT04 | |
|---|---|---|
| Price | $505.28 | $499.00 |
| Ranked | #335 of 450 in In-Ear Headphones | #344 of 450 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Harman Preference Score | 70 (measured by crinacle, via AutoEQ) | 69 (measured by crinacle, via AutoEQ) |
| Deviation From Target | 2.40 dB standard deviation | 2.79 dB standard deviation |
| Tonal Tilt | -0.45 (negative is warmer, positive brighter) | +0.02 (negative is warmer, positive brighter) |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Hybrid (1 dynamic + 3 balanced armature) |
| Drivers | 1 x 12mm dynamic | 1 x 10mm dynamic + 3 x balanced armature |
| Impedance | 32 ohms | - |
| Sensitivity | 109 dB/mW | 110 dB |
| Weight | 0 lbs (11 g) per earbud | 0 lbs (13 g) |
| Frequency Response | 10Hz - 40kHz (Manufacturer specified) | 5Hz - 40kHz (Manufacturer specified) |
| Back | Closed | Closed |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-0.4 dB at 30 Hz) | - |
Related Headphone Comparisons
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- Fatfreq Sakura vs FiiO FD5
- FiiO FD5 vs Kinera Norn
- FiiO FD5 vs Fearless Audio S8F
- iBasso IT04 vs Kinera Norn
- iBasso IT04 vs Fearless Audio S8F
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
FiiO FD5: $505.28 Amazon eBay
Pros: Crinacle’s measurement gives it a preference score of 70, and across seven hobbyist measurements on squig.link bass rises about 4 dB above target with flat sub-bass extension to 20 Hz, giving bass guitar and kick drums a full, punchy body. Its 109 dB/mW sensitivity and 32 ohm impedance mean a phone drives it easily. It rates higher than the similarly priced iBasso IT04, and the warm balance suits bass-leaning listeners.
Cons: The bass boost spills into the low mids by about 2 dB, which can thicken male vocals and make dense mixes sound slightly congested. Hobbyist measurements also show a 3.5 dB dip near 3.6 kHz and a 4.9 dB peak near 8.4 kHz, so vocals can sit a little back while cymbals and sibilants gain an edge.
Full FiiO FD5 review and specifications →
| Back | Closed |
|---|---|
| Connection | Wired |
| Deviation From Target | 2.40 dB standard deviation |
| Driver Type | Dynamic |
| Drivers | 1 x 12mm dynamic |
| Form Factor | In-ear |
| Frequency Response | 10Hz - 40kHz (Manufacturer specified) |
| Harman Preference Score | 70 (measured by crinacle, via AutoEQ) |
| Impedance | 32 ohms |
| Sensitivity | 109 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-0.4 dB at 30 Hz) |
| Tonal Tilt | -0.45 (negative is warmer, positive brighter) |
| Weight | 0 lbs (11 g) per earbud |
EQ preset to match the Harman target
Set a preamp of -3.8 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 | +1.2 dB | 0.70 |
| Peak | 155 Hz | -3.6 dB | 0.58 |
| Peak | 815 Hz | +2.7 dB | 1.04 |
| Peak | 3,920 Hz | +3.3 dB | 2.56 |
| Peak | 5,234 Hz | -3.2 dB | 5.78 |
| High shelf | 10,000 Hz | +0.4 dB | 0.70 |
| Peak | 10,000 Hz | +3.6 dB | 1.21 |
| Peak | 2,540 Hz | -1.4 dB | 4.19 |
| Peak | 40 Hz | -0.4 dB | 2.74 |
| Peak | 5,496 Hz | -1.7 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
iBasso IT04: $499.00 Amazon eBay
Pros: A preference score of 69 in crinacle’s measurement puts the IT04 in solid, listenable territory for an in-ear. The 110 dB sensitivity means it is easy to drive from a phone or dongle without a dedicated amp. At 13 g with a hybrid of one 10mm dynamic driver and three balanced armatures, it is light and uses a driver mix aimed at bass weight plus detail.
Cons: A score of 69 trails the best in-ears, so the tuning is noticeably off the Harman target in places. The FiiO FD5 has a higher rating at a similar price, which makes it the safer pick if the Harman fit matters most. It is wired only, with no wireless option.
Full iBasso IT04 review and specifications →
| Back | Closed |
|---|---|
| Connection | Wired |
| Deviation From Target | 2.79 dB standard deviation |
| Driver Type | Hybrid (1 dynamic + 3 balanced armature) |
| Drivers | 1 x 10mm dynamic + 3 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 5Hz - 40kHz (Manufacturer specified) |
| Harman Preference Score | 69 (measured by crinacle, via AutoEQ) |
| Sensitivity | 110 dB |
| Tonal Tilt | +0.02 (negative is warmer, positive brighter) |
| Weight | 0 lbs (13 g) |
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 | +2.9 dB | 0.70 |
| Peak | 230 Hz | -5.1 dB | 0.53 |
| Peak | 4,860 Hz | +5.6 dB | 2.87 |
| Peak | 770 Hz | +3.6 dB | 0.27 |
| Peak | 1,536 Hz | -4.0 dB | 1.44 |
| High shelf | 10,000 Hz | +3.7 dB | 0.70 |
| Peak | 8,235 Hz | -2.5 dB | 1.65 |
| Peak | 5,832 Hz | +1.4 dB | 4.39 |
| Peak | 2,978 Hz | +1.5 dB | 5.39 |
| Peak | 3,642 Hz | -0.9 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons