Headphone Frequency Response Test

The tool drives a single oscillator through a stereo panner and a gain stage into your browser’s audio output — the same signal path used by any web tone generator for headphones. In sweep mode the oscillator’s frequency is ramped exponentially from 20 Hz to 20 kHz as a smooth frequency sweep, so equal time is spent in each octave and the pitch climbs at a steady musical rate. In stepped mode it visits a fixed set of one-third-octave frequencies (the ISO-style 20, 25, 31.5, 40… series) so you can dwell on each one. Hold mode parks the oscillator on the single frequency set by the slider. The large readout reports the current frequency moment by moment (in Hold and Stepped modes it equals the tone being played; during a sweep it is a close real-time estimate from a timer, not a value read back from the audio hardware), and the colour band underneath tells you which part of the spectrum — sub-bass, bass, mid, presence or treble — you are currently hearing.

The channel selector pans the tone hard left, hard right, or centre. Playing the same tone on each side in turn is a quick driver-matching and left/right channel test: the two sides should sound about equally loud and have the same character. If one ear is clearly quieter, dull, buzzy or distorted while the other is clean, that points to a channel-balance issue, a loose connection, a dirty plug, or a damaged driver — though it can equally be your own hearing asymmetry, so swap the earcups left-for-right to tell them apart. The same channel-routing approach works equally well as an earphone test for in-ear monitors: run through the bass range in particular, since a headphone bass test at low frequencies is one of the most reliable ways to surface a blown or weakened driver.

Why your headphones are not — and should not be — flat. A headphone played into your ear canal does not aim for a ruler-flat response. Because of how the outer ear and ear canal naturally boost some frequencies, a headphone that measured flat on a coupler would sound thin and bright. Instead, good headphones are voiced toward a target curve — most famously the Harman target, which has an elevated bass shelf and a gentle presence rise — so the result sounds neutral to most listeners. That is why a hump in the bass or a dip around 8–10 kHz is usually intentional tuning, not a defect. Treat this test as a way to get familiar with your headphones’ voicing and to catch gross problems (a dead band, an obvious rattle, a channel imbalance), not as a substitute for a measured frequency-response graph.

What this test cannot do. It cannot produce a calibrated response curve, an absolute level in dB SPL, a distortion (THD) figure, or an impedance reading — those require lab equipment. It also can’t separate the headphone’s sound from your ears or your phone/laptop/DAC output. Two honest limits worth remembering: most adults cannot hear much above roughly 15–17 kHz (high-frequency hearing declines with age — a widely-published typical trend, not a personal measurement — you can explore your own personal ceiling with the hearing age test), and small/cheap drivers and laptop outputs often roll off the deep bass, so a missing 20–30 Hz rumble may be your hardware, not the test signal. Headphones with high impedance (above roughly 100 Ω) may sound thin from laptop headphone jacks because the output can’t fully drive them — a dedicated DAC/amp often reveals bass and treble extension that laptop outputs mask entirely.

Identifying audible distortion vs tonal character. While listening to the sweep, pay attention to whether you hear a clear, smooth tone or something extra — a buzzing, crackling, or rattling that tracks the sweep. A buzz that appears only at a specific frequency (especially in the bass) and is loudest on one driver often signals a loose component, damaged driver cone, or debris resting against the diaphragm. This is different from a headphone simply having a bass-heavy tuning: distortion sounds rough and mechanical, whereas a bass shelf sounds clean but just louder. If you hear clicks, crackling or a scraping texture anywhere in the sweep, especially under load in the low frequencies, that is worth investigating further with specialised distortion-measurement software and a measurement microphone before writing the headphone off entirely.