Test audio frequencies online from 20 Hz to 20 kHz with real browser-generated tones. Explore the audible range of your speakers, headphones and earbuds.
Continuously sweep through a frequency range to detect chassis resonances, cabinet rattles, or crossover irregularities.
Click any frequency in the interactive audible spectrum to immediately hear its tone.
Use a low volume. Listen for bass response, buzzing, rattling or driver distortion.
Listen for clarity, evenness, and vocal timbre consistency across stereo drivers.
Start quietly. High-frequency tones can sound sharp, piercing or uncomfortable.
Learn how audio frequencies work, how to generate test tones, how to test low, mid and high frequencies, how to run a frequency sweep, and how to use frequency tests safely with speakers, headphones and earbuds.
An audio frequency is the periodic vibration of air pressure that the human ear translates into sound. Frequencies are perceived as pitch: rapid vibrations sound high (like a whistle or cymbal), while slow vibrations sound low (like a bass drum or thunder).
Hertz (Hz) is the international unit of frequency representing one complete oscillation cycle per second. Named after physicist Heinrich Hertz, 1 Hz is one cycle per second. 1 kilohertz (1 kHz) represents 1,000 complete oscillation cycles every second.
The human ear is generally capable of detecting acoustic vibrations spanning from 20 Hz to 20,000 Hz (20 kHz). Frequencies below 20 Hz are termed infrasound, while frequencies above 20 kHz are termed ultrasound.
Low frequencies (20 Hz–250 Hz) test subwoofer excursion and woofer enclosures. Play tones starting at 100 Hz and step downwards toward 30 Hz at moderate volume. Listen for physical cabinet rattling, voice coil scraping, or sympathetic room buzzing.
Mid frequencies (250 Hz–4 kHz) encompass human speech and core musical fundamentals. Evaluate whether tones in this band sound smooth, balanced between left and right channels, and free of harsh distortion.
High frequencies (5 kHz–20 kHz) assess tweeter fidelity and acoustic brilliance. Keep digital volume at 20%–30% to prevent ear fatigue. Listen for crisp, transparent highs without excessive graininess or hiss.
Position yourself in the center of your listening triangle. Generate tones at 60 Hz, 1 kHz, and 10 kHz to ensure both speakers produce equal volume and consistent tonality without cabinet vibration.
Put on your over-ear or on-ear headphones. Because headphone drivers sit directly outside your ear canal, begin at a low gain setting. Check whether low bass remains centered and whether high frequencies sound equal in both ears.
In-ear monitors and earbuds depend entirely on an airtight ear tip seal. If deep bass (below 80 Hz) sounds thin or absent, try different tip sizes before evaluating frequency reproduction.
Use the Channel Selector to isolate the LEFT channel, then switch to RIGHT. Ensure that when Left is selected, zero sound bleeds into the right channel, verifying clean stereo channel separation.
Switch to BOTH or MONO. When identical frequency signals play through both channels in phase, the auditory image should appear solidly phantom-centered directly midway between your ears.
A frequency sweep is a continuous audio tone whose frequency steadily climbs or descends across the audible spectrum. Sweeps immediately reveal crossover dips and acoustic resonances that single static tones miss.
Select the 20 Hz → 20 kHz range with a 10-second or 20-second duration. Click 'START SWEEP'. Listen for a smooth, uninterrupted transition from deep rumble to high pitch without sudden loudness drops.
A tone generator synthesizes mathematically defined periodic waveforms. Select your frequency via the logarithmic slider or numeric input, choose Sine wave, and click Play. Always adjust gain smoothly.
A sine wave is the purest acoustic waveform in physics. It contains no harmonics or overtones beyond its single fundamental frequency, making it the essential standard for testing driver distortion.
A triangle wave contains the fundamental frequency plus odd harmonics (3rd, 5th, 7th) with amplitudes diminishing as the square of the harmonic number ($1/n^2$), producing a warm, flute-like tone.
A square wave contains prominent odd harmonic overtones ($1/n$), generating a rich, hollow, buzzy acoustic texture often used in digital synthesizer synthesis and circuit clipping analysis.
A sawtooth wave contains both even and odd harmonics across the spectrum, producing an extremely bright, sharp, and rich tone with maximum high-frequency harmonic content.
Human ears are not equally sensitive across all frequencies (described by the Fletcher-Munson equal-loudness contours). Furthermore, physical speaker drivers have sharp low-end roll-offs, and age reduces high-frequency reception.
Low frequencies demand substantial physical cone displacement. If you hear a buzz, it is almost always caused by loose screws, speaker grille vibration, desk resonance, or a loose dust cap.
The human ear canal naturally resonates between 2 kHz and 4 kHz to amplify human speech. Pure high-frequency sine tones in this range can feel intense or piercing even at moderate volume settings.
Presbycusis (natural age-related hearing change) gradually reduces hair cell sensitivity in the cochlea responsible for high frequencies. Adults over 30 commonly top out around 15–16 kHz, while children may hear up to 19–20 kHz.
Always begin testing at 25%–30% volume. Never turn up your volume to 'hunt' for high-frequency tones you cannot hear, as high digital energy can blow delicate tweeters and cause ear fatigue.
Measuring true acoustic frequency response requires a calibrated measurement microphone placed in an acoustically treated room, alongside specialized measurement software. A web browser can only synthesize accurate output signals.
Audio frequency represents the rate of acoustic vibration per second produced by a sound source, measured in Hertz (Hz). Higher frequencies correspond to higher perceived pitch, while lower frequencies correspond to deep bass.
Hertz (Hz) is the standard International Unit of frequency, denoting one complete wave cycle per second. 1 kilohertz (kHz) equals 1,000 complete cycles per second.
The standard theoretical range for human hearing spans from approximately 20 Hz (deep sub-bass) to 20,000 Hz (20 kHz, ultra-high treble), though high-frequency perception naturally decreases with age.
An audio frequency test is a diagnostic procedure where controlled tones or frequency sweeps are generated to inspect how cleanly playback hardware reproduces specific portions of the audible acoustic spectrum.
Select your desired waveform (typically Sine for clean diagnostic tones), set a safe moderate volume (30%), select your output channel, and click 'START FREQUENCY TEST'. Adjust the frequency slider to explore 20 Hz through 20 kHz.
Use the Low Frequency test presets between 20 Hz and 120 Hz. Listen for deep bass clarity, and check whether your speaker cabinet, desk, or headphone enclosure buzzes or rattles.
Start quietly with tones between 5 kHz and 18 kHz. High frequencies carry significant energy and can sound piercing; verify they play cleanly without hiss or excessive harshness.
Position yourself equidistant between your left and right speakers in speaker mode, set volume low, and run a frequency sweep to identify resonant cabinet buzzes or crossover dropouts.
Put on your headphones, set volume at 25%–30%, and use channel routing (Left, Right, Both) and stepped presets to test driver balance and driver extension across low and high octaves.
Ensure your earbud tips create an airtight seal in your ear canal (essential for sub-bass audibility below 100 Hz), then test low and high tones sequentially.
A frequency sweep is an audio tone that smoothly transitions pitch across a range of frequencies (e.g. 20 Hz to 20 kHz) to detect acoustic resonances, enclosure rattles, and driver distortion.
A sine wave is a pure, fundamental acoustic tone consisting of exactly one frequency without any additional harmonic overtones. It is the gold standard for audio diagnostic testing.
A square wave alternates instantaneously between two peak amplitudes. It contains rich, odd harmonic frequencies and is commonly used to test digital audio linearity and synthesizer textures.
A triangle wave contains odd harmonics like a square wave, but their energy drops off exponentially ($1/n^2$), producing a softer, flute-like tone.
A sawtooth wave ramps linearly upward and drops sharply, generating both even and odd harmonics for an intense, bright, brass-like acoustic profile.
20 Hz is at the absolute physical threshold of human hearing and requires high acoustic pressure to perceive. Most desktop speakers and budget headphones cannot reproduce 20 Hz at audible amplitudes.
Human hearing naturally loses sensitivity to frequencies above 15–17 kHz with normal age-related hearing change (presbycusis) and ambient environmental noise exposure.
Sub-bass vibrations frequently cause loose speaker grilles, internal cabinet joints, or nearby tabletop items to vibrate sympathetic to the sound wave.
Human hearing is exceptionally sensitive in the 2 kHz to 5 kHz region due to the natural resonance of the human ear canal, making high-amplitude high tones feel piercing.
No. Measuring physical speaker frequency response requires a calibrated measurement microphone placed in an anechoic chamber or reflection-free acoustic space running impulse response software.
No. Objective headphone response measurement requires an IEC 60318-4 ear simulator coupler, artificial pinna fixture, and calibrated hardware analyzer.
No. Sound Pressure Level (SPL) requires a physical microphone calibrated to decibels relative to $20\,\mu\text{Pa}$. This tool measures browser digital signal level in dBFS.
No. Total Harmonic Distortion (THD) requires capturing analog output with calibrated audio analyzers to measure physical harmonic distortion products.
No. All test tones are generated purely inside your browser using the Web Audio API. No microphone access is requested or used.
Yes, when used responsibly. Always begin at a low volume (the tool defaults to 30%), increase gradually, and never use loud volume settings with high-frequency tones.
Generate precise test tones from 20 Hz to 20 kHz and explore low, mid and high frequencies directly in your browser.
