Short answer: the KLH Ultimate One, though neither ranks well in its class. It ranks #197 of 216 over-ear headphones by sound quality, rated 2.5/5, at $325.11; the iBasso SR1 ranks #211, rated 1.5/5, and costs $399, so there is little reason to consider the other one. Both are rated below 3.0/5 among the 216 over-ear headphones, so if sound quality matters, consider the HIFIMAN Ananda Nano instead, ranked #4 at $319.
The KLH Ultimate One is the better-sounding option. Bass from 60 to 200 Hz runs about 8.5 dB above target with sub-bass 5 dB up, so bass lovers get heavy, rumbling lows from an open headphone. Watch for: In oratory1990’s measurement the treble also sits about 5 dB above target from 3 to 16 kHz with a 9.6 dB peak near 6 kHz, which can make vocals and cymbals sound sharp and tiring at volume.
Why pick the iBasso SR1: A low 22 ohm impedance means the 50 mm dynamic driver runs from a phone or laptop without a separate amp. The catch: Crinacle’s measurement gives it a preference score of only 25, with a steep warm tilt and large deviations of about 4.5 dB on average from the Harman target, so most listeners will hear a muffled, uneven balance.
Buy the KLH Ultimate One. It is rated higher for sound quality than the iBasso SR1 and costs less, so only choose the other one for a particular feature it does better.
Still deciding? The full Headphones rankings cover every ranked option.
Specifications Side By Side
| KLH Ultimate One | iBasso SR1 | |
|---|---|---|
| Price | $325.11 | $399.00 |
| Ranked | #197 of 216 in Over-Ear Headphones | #211 of 216 in Over-Ear Headphones |
| Form Factor | Over-ear | Over-ear |
| Harman Preference Score | 49 (measured by oratory1990, via AutoEQ) | 25 (measured by crinacle, via AutoEQ) |
| Deviation From Target | 3.96 dB standard deviation | 4.48 dB standard deviation |
| Tonal Tilt | -1.03 (negative is warmer, positive brighter) | -2.12 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+2.6 dB at 30 Hz) | - |
| Connection | Wired | Wired |
| Back | Open | Semi-open |
| Driver Type | Dynamic | Dynamic |
| Drivers | 1 x 50mm dynamic | 1 x 50mm dynamic |
| Impedance | 32 ohms | 22 ohms |
| Sensitivity | 97 dB/mW | 108 dB |
| Weight | 0.7 lbs (340 g) | 0.9 lbs (420 g) |
| Frequency Response | 18Hz - 22kHz (Manufacturer specified) | 3Hz - 40kHz (Manufacturer specified) |
| Built-in Microphone | No | No |
Related Headphone Comparisons
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- KLH Ultimate One vs Sennheiser Momentum 4 Wireless
- Audio-Technica ATH-A990Z vs iBasso SR1
- Beyerdynamic DT 770 M vs iBasso SR1
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
KLH Ultimate One: $325.11 Amazon eBay
Pros: Bass from 60 to 200 Hz runs about 8.5 dB above target with sub-bass 5 dB up, so bass lovers get heavy, rumbling lows from an open headphone. At 32 ohms and 97 dB/mW it plays at moderate volume from a phone or laptop without an amp, and it rates level with the Audio-Technica ATH-AD900X and AKG K271 MKII.
Cons: In oratory1990’s measurement the treble also sits about 5 dB above target from 3 to 16 kHz with a 9.6 dB peak near 6 kHz, which can make vocals and cymbals sound sharp and tiring at volume. A deviation of nearly 4 dB and a preference score of 49 mean most listeners will hear a heavily colored sound, and the open back leaks noise both ways. The Neumann NDH20 rates slightly higher.
Full KLH Ultimate One review and specifications →
| Released | 2020 (6 years ago) |
|---|---|
| Back | Open |
| Built-in Microphone | No |
| Connection | Wired |
| Deviation From Target | 3.96 dB standard deviation |
| Driver Type | Dynamic |
| Drivers | 1 x 50mm dynamic |
| Form Factor | Over-ear |
| Frequency Response | 18Hz - 22kHz (Manufacturer specified) |
| Harman Preference Score | 49 (measured by oratory1990, via AutoEQ) |
| Impedance | 32 ohms |
| Sensitivity | 97 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+2.6 dB at 30 Hz) |
| Tonal Tilt | -1.03 (negative is warmer, positive brighter) |
| Weight | 0.7 lbs (340 g) |
EQ preset to match the Harman target
Set a preamp of -6.1 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 | +0.6 dB | 0.70 |
| Peak | 1,122 Hz | +6.6 dB | 0.74 |
| Peak | 206 Hz | -7.1 dB | 0.57 |
| Peak | 478 Hz | +3.3 dB | 1.24 |
| Peak | 2,632 Hz | -5.8 dB | 2.57 |
| High shelf | 10,000 Hz | -3.4 dB | 0.70 |
| Peak | 6,143 Hz | -4.3 dB | 6.00 |
| Peak | 4,905 Hz | +2.7 dB | 2.64 |
| Peak | 43 Hz | -0.6 dB | 2.14 |
| Peak | 5,841 Hz | -1.7 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
iBasso SR1: $399.00 Amazon eBay
Pros: A low 22 ohm impedance means the 50 mm dynamic driver runs from a phone or laptop without a separate amp. Its very warm tilt can appeal to listeners who want a dark, bass-heavy sound and dislike any brightness.
Cons: Crinacle’s measurement gives it a preference score of only 25, with a steep warm tilt and large deviations of about 4.5 dB on average from the Harman target, so most listeners will hear a muffled, uneven balance. The semi-open back leaks sound and lets outside noise in, and the cheaper Sony WH-1000XM5 rates noticeably higher.
Full iBasso SR1 review and specifications →
| Released | 2018 (8 years ago) |
|---|---|
| Back | Semi-open |
| Built-in Microphone | No |
| Connection | Wired |
| Deviation From Target | 4.48 dB standard deviation |
| Driver Type | Dynamic |
| Drivers | 1 x 50mm dynamic |
| Form Factor | Over-ear |
| Frequency Response | 3Hz - 40kHz (Manufacturer specified) |
| Harman Preference Score | 25 (measured by crinacle, via AutoEQ) |
| Impedance | 22 ohms |
| Sensitivity | 108 dB |
| Tonal Tilt | -2.12 (negative is warmer, positive brighter) |
| Weight | 0.9 lbs (420 g) |
EQ preset to match the Harman target
Set a preamp of -6.8 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 | +1.7 dB | 0.70 |
| Peak | 196 Hz | -5.9 dB | 0.52 |
| Peak | 5,980 Hz | +10.5 dB | 0.63 |
| Peak | 103 Hz | -0.7 dB | 3.84 |
| Peak | 5,700 Hz | -13.9 dB | 2.77 |
| High shelf | 10,000 Hz | +4.5 dB | 0.70 |
| Peak | 1,100 Hz | -1.1 dB | 2.13 |
| Peak | 3,462 Hz | +2.2 dB | 4.43 |
| Peak | 8,402 Hz | -2.5 dB | 4.80 |
| Peak | 3,096 Hz | -1.9 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons