Short answer: the Koss KPH30i. It ranks #104 of 216 over-ear headphones by sound quality, rated 3.7/5, at $29.99; the Superlux HD 681 ranks #165, rated 3.1/5, and costs $33.29, so there is little reason to consider the other one.
The Koss KPH30i is the better-sounding pick. A very low price makes it an easy disposable or backup pair, and the 60 ohm, 101 dB sensitivity runs from any phone. The tradeoff: Sub-bass is nearly 12 dB under target below 60 Hz, so there is no rumble and deep bass is essentially missing.
The case for the Superlux HD 681: A very low price and a 32 ohm, 98 dB/mW load make it an easy pick for use straight from a phone or laptop. Watch for: Sub-bass sits 9.7 dB below target in oratory1990’s measurement and falls 6 dB short by 42 Hz, so bass sounds thin and lacks impact.
Buy the Koss KPH30i. It is rated higher for sound quality than the Superlux HD 681 and costs less, so it is the default pick unless a specific strength of the other one matters more to you.
Want more options? Browse the full Headphones rankings.
Specifications Side By Side
| Koss KPH30i | Superlux HD 681 | |
|---|---|---|
| Price | $29.99 | $33.29 |
| Ranked | #104 of 216 in Over-Ear Headphones | #165 of 216 in Over-Ear Headphones |
| Form Factor | Over-ear | Over-ear |
| Harman Preference Score | 76 (measured by oratory1990, via AutoEQ) | 61 (measured by oratory1990, via AutoEQ) |
| Deviation From Target | 2.62 dB standard deviation | 2.58 dB standard deviation |
| Tonal Tilt | -0.38 (negative is warmer, positive brighter) | +1.34 (negative is warmer, positive brighter) |
| Sub-bass Extension | Falls 6 dB below target at 50 Hz (-13.9 dB at 30 Hz) | Falls 6 dB below target at 42 Hz (-9.8 dB at 30 Hz) |
| Connection | Wired | Wired |
| Back | Open | Semi-open |
| Driver Type | Dynamic | Dynamic |
| Drivers | 1 x 35mm dynamic | 1 x 50mm dynamic |
| Impedance | 60 ohms | 32 ohms |
| Sensitivity | 101 dB SPL/1mW | 98 dB/mW |
| Frequency Response | 15Hz - 25kHz (Manufacturer specified) | 10Hz - 30kHz (Manufacturer specified) |
| Built-in Microphone | Yes | No |
| Weight | - | 0.5 lbs (230 g) |
Related Headphone Comparisons
How Koss KPH30i compares with other leading options:
- Superlux HD 660 Pro 150 Ohm vs Koss KPH30i
- FiiO EH11 vs Koss KPH30i
- Koss KPH30i vs Koss KPH40
- Koss KPH30i vs Koss KSC75
- FiiO EH11 vs Superlux HD 681
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
Koss KPH30i: $29.99 Amazon eBay
Pros: A very low price makes it an easy disposable or backup pair, and the 60 ohm, 101 dB sensitivity runs from any phone. It has an inline microphone for calls and the open on-ear design is light and airy. Bass from 60 Hz to the upper mids stays within about 0.6 dB of the Harman target, which gives a fairly balanced core.
Cons: Sub-bass is nearly 12 dB under target below 60 Hz, so there is no rumble and deep bass is essentially missing. An 11.8 dB dip near 4.2 kHz makes vocals and detail recede, and treble from 3 to 10 kHz is about 2.8 dB low. The open back leaks sound and offers no isolation, so it suits quiet rooms only.
Full Koss KPH30i review and specifications →
| Back | Open |
|---|---|
| Built-in Microphone | Yes |
| Connection | Wired |
| Deviation From Target | 2.62 dB standard deviation |
| Driver Type | Dynamic |
| Drivers | 1 x 35mm dynamic |
| Form Factor | Over-ear |
| Frequency Response | 15Hz - 25kHz (Manufacturer specified) |
| Harman Preference Score | 76 (measured by oratory1990, via AutoEQ) |
| Impedance | 60 ohms |
| Sensitivity | 101 dB SPL/1mW |
| Sub-bass Extension | Falls 6 dB below target at 50 Hz (-13.9 dB at 30 Hz) |
| Tonal Tilt | -0.38 (negative is warmer, positive brighter) |
EQ preset to match the Harman target
Set a preamp of -6.3 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 | +6.8 dB | 0.70 |
| Peak | 109 Hz | -4.7 dB | 0.47 |
| Peak | 2,979 Hz | +1.7 dB | 0.18 |
| Peak | 1,956 Hz | -4.1 dB | 2.01 |
| Peak | 49 Hz | +2.5 dB | 2.08 |
| High shelf | 10,000 Hz | +0.1 dB | 0.70 |
| Peak | 5,070 Hz | -5.0 dB | 5.22 |
| Peak | 3,844 Hz | +2.9 dB | 5.95 |
| Peak | 6,348 Hz | +2.6 dB | 5.99 |
| Peak | 502 Hz | +0.3 dB | 1.44 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Superlux HD 681: $33.29 B&H Photo Video eBay
Pros: A very low price and a 32 ohm, 98 dB/mW load make it an easy pick for use straight from a phone or laptop. From the upper midrange through the air band its response stays within 2 dB of target on average, which suits listeners who like a bright or studio-flat balance. It rates higher than the Koss KPH40 at a similar price.
Cons: Sub-bass sits 9.7 dB below target in oratory1990’s measurement and falls 6 dB short by 42 Hz, so bass sounds thin and lacks impact. A 5.7 dB peak at 4.8 kHz right next to a 5.1 dB dip at 4.1 kHz can make vocals and guitars edgy, and the semi-open back lets some sound escape. The AKG K240 Studio and HyperX Cloud Alpha rate higher for a little more money.
Full Superlux HD 681 review and specifications →
| Back | Semi-open |
|---|---|
| Built-in Microphone | No |
| Connection | Wired |
| Deviation From Target | 2.58 dB standard deviation |
| Driver Type | Dynamic |
| Drivers | 1 x 50mm dynamic |
| Form Factor | Over-ear |
| Frequency Response | 10Hz - 30kHz (Manufacturer specified) |
| Harman Preference Score | 61 (measured by oratory1990, via AutoEQ) |
| Impedance | 32 ohms |
| Sensitivity | 98 dB/mW |
| Sub-bass Extension | Falls 6 dB below target at 42 Hz (-9.8 dB at 30 Hz) |
| Tonal Tilt | +1.34 (negative is warmer, positive brighter) |
| Weight | 0.5 lbs (230 g) |
EQ preset to match the Harman target
Set a preamp of -5.8 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 | +5.8 dB | 0.70 |
| Peak | 496 Hz | +2.4 dB | 1.05 |
| Peak | 1,105 Hz | -1.8 dB | 0.57 |
| Peak | 5,194 Hz | -6.1 dB | 4.12 |
| Peak | 174 Hz | +1.0 dB | 1.11 |
| High shelf | 10,000 Hz | -3.2 dB | 0.70 |
| Peak | 7,758 Hz | -2.3 dB | 3.68 |
| Peak | 3,826 Hz | +3.2 dB | 5.94 |
| Peak | 2,458 Hz | -1.4 dB | 3.46 |
| Peak | 65 Hz | -0.5 dB | 2.20 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons