Short answer: the ISN Audio Neo 5. Both are rated 3.4/5 for sound quality (#855 and #857 of 1291 in-ear headphones), and the ISN Audio Neo 5 costs $289 against $299 for the Penon Serial, with sound quality a draw, the lower price decides it.
What the ISN Audio Neo 5 does well: A broadly balanced tuning with a preference score of 67 against the Harman target. The catch: Treble about 4 dB below target from 3 to 10 kHz, which can sound dull or veiled next to brighter headphones.
The case for the Penon Serial: A broadly balanced tuning with a preference score of 67 against the Harman target. Watch for: Treble about 4 dB below target from 3 to 10 kHz, which can sound dull or veiled next to brighter headphones.
Buy the ISN Audio Neo 5. Both are rated the same for sound quality, and it costs $10 less than the Penon Serial.
Still deciding? The full Headphones rankings cover every ranked option.
A broadly balanced tuning with a preference score of 67 against the Harman target.
Penon Audio $289.00 eBay
A broadly balanced tuning with a preference score of 67 against the Harman target.
Penon Audio $299.00 eBayPrices on this page were last checked October 16, 2026 at 5:46 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.
As an eBay Partner, we may be compensated if you make a purchase.
Specifications Side By Side
| ISN Audio Neo 5 | Penon Serial | |
|---|---|---|
| Price | $289.00 | $299.00 |
| Ranked | #855 of 1291 in In-Ear Headphones | #857 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 67 (median of 5 squig.link measurements, calibrated to AutoEQ) | 67 (median of 7 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.28 dB standard deviation | 2.44 dB standard deviation |
| Tonal Tilt | -0.92 (negative is warmer, positive brighter) | -0.68 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+0.1 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-1.5 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Hybrid | Dynamic |
| Drivers | 1 DD + 4 BA (1 x 10mm dynamic driver + 4 Knowles balanced armature) | 3 x dynamic drivers (10mm bio-diaphragm + 8mm titanium-plated + 6mm PU) |
| Impedance | 26 ohms | 18 ohms |
| Sensitivity | 110 dB | 103 dB |
| Frequency Response | 10Hz - 20kHz | 20Hz - 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 ISN Audio Neo 5 from dl, iemocean, isaiahse, soundignity and tonedeafmonk; the Penon Serial from dl, harpo, hbb, jaytiss, mmagtech, nymz and tgx78, all via squig.link.
Related Headphone Comparisons
How ISN Audio Neo 5 compares with other leading options: