Frequency Response Test
A listening check, not a lab curve. Play a sine sweep from 20 Hz to 20 kHz and listen for where the tone disappears. Play a single tone, or step through low bass notes. Free, and it runs in your browser.
Start quiet. Set your system volume low, then raise this slider slowly. Very low tones at high volume can damage small speakers and earbuds, and high tones above 10 kHz can be painful even when they seem faint. Take headphones off if anything hurts.
1. Frequency sweep, 20 Hz to 20 kHz
The filled bar is the sine while it plays. It is not a measured response curve.
Press "I can hear it" when the low rumble first appears, and "It stopped" when the high whistle fades out. Your reaction time adds a small offset, so run it in both directions and compare.
2. Play a single frequency
3. Bass extension test
Play each tone and tick the ones you can hear as a clean, steady note. A buzz or rattle is distortion, not bass, so leave it unticked. Low notes sound much quieter than mid tones at the same level: resist the urge to turn it way up.
How to read your frequency response test
How the test works
The sweep plays a pure sine tone that glides from 20 Hz to 20 kHz, log-spaced so each octave gets the same time. The number on screen is that oscillator frequency. You listen for where the tone appears and where it disappears. Use the single-tone player to check an edge again, and the bass steps to find the lowest note you can still hear as a steady tone.
Why boxes say 20 Hz to 20 kHz
Almost every box says "20 Hz to 20 kHz". The catch is the tolerance. A spec quoted at ±3 dB means something; one quoted at ±10 dB, or with no tolerance at all, can mean the 20 Hz tone is barely a whisper. On a listening check, laptop and phone speakers often go quiet below 150 to 200 Hz, small Bluetooth speakers around 60 to 80 Hz, and good headphones often stay audible down to 20 to 30 Hz. This page cannot turn that into a decibel curve.
Your ears, the seal and the room
The high limit you find is usually set by your ears, not the driver. Most adults stop hearing somewhere between 14 and 17 kHz, and it drops with age. Run the hearing test on a pair you trust to tell the two apart.
Cheap earbuds lose bass mostly through a poor seal. If the tip does not close off your ear canal, low notes leak out, so try a bigger tip before blaming the driver. With speakers, the room matters: walls and corners boost some bass notes and cancel others, so move around while a low tone plays.
The honest limits
This is a listening test, not a calibrated measurement. It cannot draw a response curve or tell you how many decibels quieter 30 Hz is than 1 kHz. Your sound card, browser, Bluetooth codec and any EQ or "bass boost" setting all sit in the chain. Use it to compare gear side by side at the same volume, not to prove a spec sheet wrong to the decibel.
Related tools
Check your own hearing range with the hearing test, confirm left and right channels with the headphone test, play custom tones and waveforms with the tone generator, and find out whether you can really hear hi-res audio with the audio blind test.
Frequently asked questions
Is a 20 Hz to 20 kHz result a frequency-response curve?
No. This is a listening check. The page plays a sine that glides from 20 Hz to 20 kHz, or from 20 kHz down to 20 Hz. You mark where the tone appears and where it disappears. The microphone is never used, and nothing on the page is a measured response graph.
What should I listen for?
On a low-to-high sweep, press "I can hear it" when the rumble first appears and "It stopped" when the high tone fades out. On a high-to-low sweep, mark when the high tone appears and when the bass disappears. A slow press shifts the mark, so run both directions. The single-tone control and the bass steps play the same sine so you can check an edge again.
How do I stop the sound?
Use Stop all sound, Stop sweep while a sweep is running, or Stop tone while a single frequency is playing. Press a bass note button again to stop that note. Leaving the page stops the tone and closes the audio context.
Why does the sweep not start on its own?
High tones can hurt, and strong low tones can stress small drivers. No sweep starts on load. A sweep, single tone, or bass note starts only after a play click. That click creates or resumes the audio context. The volume slider starts at 15%. A saved level comes back no higher than 40%. Gain is the square of volume/100, so those levels stay under full scale until you raise the slider.
What limit does the browser set?
The test needs the Web Audio API. If the browser has no AudioContext, the page says it cannot play tones. The sine only runs from 20 Hz to 20 kHz. A browser can generate 20 kHz, but your ears, headphones, speakers, or Bluetooth link may drop it earlier. The page cannot tell those apart.
What frequency is the number on screen?
During a sweep the large number matches the sine oscillator: a log glide over the 10, 20, or 30 seconds you chose, taken from the audio clock. The single-tone number is the frequency Play uses, and while it is playing the oscillator is set to that same value. Bass buttons play 20, 25, 31.5, 40, 50, 63, and 80 Hz. Ticks are notes you say you hear, not a lab reading.