Superlux HD 681

Budget$30–45

A budget stand-in for far pricier open-back references — good enough to hear channel balance and distortion differences in blind tests.

Price links coming soon

Pros and cons

Pros

  • 32 Ω impedance is easy to drive from a phone, laptop, or low-cost headphone output.
  • Semi-open earcups make left/right channel differences easier to hear than a closed-back pair.
  • At $30 to $45, it is the least expensive over-ear pick in this catalog.
  • A fixed cable removes one connection point to troubleshoot during a test.

Cons

  • The fixed cable cannot be replaced if it is damaged or worn through.
  • Semi-open earcups leak sound into the room and let background noise in.
  • Build and earpads are basic compared with the reference picks.
  • It is not a substitute for a closed-back pair when isolation is the point of the test.

Key specs

TypeSemi-open, over-ear
Impedance32 Ω
CableFixed

What these headphones are for

The Superlux HD-681 is the budget over-ear pick in this catalog. It is semi-open, 32 Ω, and listed at $30 to $45. That combination makes it a low-cost way to run channel checks, stereo perception tests, and blind frequency tests without dedicating a reference pair to the job. The open presentation also makes it easier to hear when one channel is louder or cleaner than the other.

It is not a closed-back monitoring tool. Semi-open earcups leak sound into the room and let room noise reach your ears, so a fan, a street, or a nearby conversation can mask quiet test signals. Use it in a quiet room, and do not expect it to replace a closed-back pair for microphone monitoring or noisy environments.

How to use them in a test

Before a test, check that both earcups sit around your ears at a similar angle and that the headband is not pressing harder on one side. Human hearing sensitivity changes with level, so set a comfortable listening volume with pink noise and keep it the same for both channels. Do not raise the level to make a quiet sweep audible.

Disable all operating system audio enhancements, spatial virtualization filters, and equalizer presets before loading a test page. Software processing alters phase relationships and frequency balance, invalidating test scores. Run a quick left-right channel verification tone to confirm correct stereo orientation. If you have access to a second pair of headphones, running the same blind test on both models helps distinguish personal auditory thresholds from equipment limitations.

  • Adjust the headband so the earcups seal symmetrically around both ears without creating uneven clamp pressure.
  • Set listening volume to a comfortable moderate level using pink noise before starting tone sweeps.
  • Deactivate all digital sound processing, EQ curves, and surround simulation tools in your audio playback settings.
  • Run the stereo perception test and blind frequency test to establish baseline auditory performance.

Compared with the other picks

The Superlux HD-681 is the budget pick here, next to the value-tier Sony MDR-7506 and the reference Sennheiser HD 600. At $30 to $45 and 32 Ω, the HD-681 is the easiest of the three to drive from a consumer jack. The $90 to $120 Sony MDR-7506 is closed-back, 63 Ω, and built for isolation and noise checks. The $300 to $350 Sennheiser HD 600 is the open-back reference, with 300 Ω impedance and a detachable cable.

ModelTypeImpedanceCablePriceBest for
Superlux HD-681Semi-open, over-ear32 ΩFixed$30–45Budget listening tests and channel balance checks
Sennheiser HD 600Open-back, over-ear300 ΩDetachable$300–350Reference open-back listening and long ABX drills
Sony MDR-7506Closed-back, over-ear63 ΩCoiled, fixed$90–120Closed-back isolation, noise checks, and mic tracking

Tests this suits