Short answer: the NF Acous NM25 on measured sound quality, the ISN Audio Neo 3 on price. The NF Acous NM25 ranks #985 of 1369 in-ear headphones, rated 3.2/5, at $199. The ISN Audio Neo 3 ranks #1054, rated 3.1/5, at $99, $100 cheaper.
Why pick the NF Acous NM25: A single dynamic driver earphone with a bright, detailed character that suits V-shaped and neutral listeners, with a low end that stays within 6 dB of target down to 20 Hz. The catch: Treble runs about 6 dB above target from 6 to 16 kHz, peaking 12.3 dB near 11.2 kHz in the median of 7 hobbyist measurements on squig.link, so cymbals, hi-hats and sibilance can sound hot and fatiguing at higher volume.
Why pick the ISN Audio Neo 3: A published AutoEQ preset corrects its response toward the Harman target, so a few minutes of EQ setup closes most of the gap. The catch: Treble about 2 dB below target from 3 to 10 kHz, which can sound dull or veiled next to brighter headphones.
Buy the NF Acous NM25 when sound quality outweighs the price for you, and the ISN Audio Neo 3 when the price outweighs sound quality instead.
Looking for alternatives? See the complete Headphones rankings.
A single dynamic driver earphone with a bright, detailed character that suits V-shaped and neutral listeners, with a low end that stays within 6 dB of target down to 20 Hz.
Amazon $199.00 eBay
A published AutoEQ preset corrects its response toward the Harman target, so a few minutes of EQ setup closes most of the gap.
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Specifications Side By Side
| NF Acous NM25 | ISN Audio Neo 3 | |
|---|---|---|
| Price | $199.00 | 99.00 |
| Ranked | #985 of 1369 in In-Ear Headphones | #1054 of 1369 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 64 (median of 7 squig.link measurements, calibrated to AutoEQ) | 63 (median of 6 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.42 dB standard deviation | 2.70 dB standard deviation |
| Tonal Tilt | +0.93 (negative is warmer, positive brighter) | -0.70 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-1.5 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-0.9 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Hybrid (2 Dynamic + 1 Planar) |
| Drivers | 1 x dynamic | 2 x 6mm dynamic drivers (1 low, 1 mid) + 1 x 5.8mm micro-planar driver (high) |
| Impedance | 32 ohms | 15 ohms |
| Sensitivity | 108 dB/mW | 105 dB |
| Frequency Response | - | 10Hz - 20kHz |
Frequency Response Compared
Both headphones’ measurements overlaid on the Harman target. Above the target sounds louder in that range, below it quieter. Each curve is the median of several independent measurements, shifted so its 500 Hz to 2 kHz average sits at 0 dB, so only the tuning is compared.
Measurement data: the NF Acous NM25 from cqtek, digaoreviews, faxepremium, musicafe, practiphile, pw, tonedeafmonk and treblewellxtended; the ISN Audio Neo 3 from avishai, flare, pw, soundcheck39, theaudiostore and treblewellxtended, all via squig.link.
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