Headphone Frequency Response Test
Play a smooth 20 Hz–20 kHz log sweep or pick stepped test tones through your headphones, run a left / right / both driver-matching check, and use the bass/mid/treble guide to listen for where your headphones feel strong, weak or harsh. The big readout always shows the frequency that is playing.
ℹ This is an uncalibrated, by-ear test, not a measurement. What you hear is the combination of your headphone’s tuning + your ears (HRTF, age-related high-frequency loss) + your device’s output — the tool cannot separate them and cannot show a real response curve in dB. Headphones are intentionally not flat: good ones are voiced toward a target curve (such as the Harman target), so a strong bass shelf or a gentle treble dip is by design, not a fault. A true headphone frequency response needs a measurement rig (artificial-ear coupler) and software like REW. ⚠ Safety: headphones sit right against your ears — start at a low volume, never chase very low or very high tones by turning up, and stop if anything is uncomfortable. Very loud tones can damage hearing and small drivers.
How It Works
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. In sweep mode the oscillator’s frequency is ramped exponentially from 20 Hz to 20 kHz, 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 check: 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.
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), 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.