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Frequencies

Sound frequencies

Play and explore more than 500 frequencies – from 1 Hz infrasound to 40 kHz ultrasound.

Frequency is how many times a sound wave repeats each second, measured in hertz (Hz). We hear it as pitch: low frequencies sound deep, high frequencies sound shrill. Healthy young ears span roughly 20 Hz to 20,000 Hz – ten octaves.

Every page below has a free online tone generator plus the period, wavelength, nearest musical note, harmonics and which animals can hear that frequency.

The frequency spectrum at a glance

BandRangeWhat you hear
Infrasound0–20 HzBelow the range of human pitch perception – felt as pressure or vibration. Produced by earthquakes, volcanoes, wind turbines, large engines and elephants.
Sub-bass20–60 HzThe deep rumble felt in the chest – kick-drum weight, organ pedal notes, distant thunder.
Bass60–250 HzWhere most musical bass lines and the fundamentals of male voices live. Gives sound its warmth and body.
Low midrange250–500 HzThe fundamentals of many instruments and female voices. Too much here sounds 'muddy' or boxy.
Midrange500–2,000 HzThe core of most sounds: vowels, melody instruments, and much of what makes speech intelligible.
Upper midrange2,000–4,000 HzWhere the ear is most sensitive. Consonants, attack and presence – harsh if overdone.
Presence4,000–6,000 HzDefinition and clarity: the 'edge' of a voice or guitar, the bite of brass.
Brilliance (air)6,000–20,000 HzSparkle, sibilance, cymbal shimmer and the sense of air and space. Hearing here declines with age.
Ultrasound> 20,000 HzAbove human hearing. Used by bats and dolphins, medical imaging, cleaning baths and parking sensors.

Notable frequencies

7.83 Hz
The fundamental Schumann resonance – electromagnetic (not acoustic) resonances of the cavity between Earth's surface and the…
16.35 Hz
C0, the lowest C in standard scientific pitch notation. The longest 32-foot organ pipes sound close to this – felt more than…
19 Hz
Sometimes called the 'fear frequency': in 1998 engineer Vic Tandy linked unease in a 'haunted' lab to a fan producing a 19 Hz…
20 Hz
The conventional lower limit of human hearing. Below about 20 Hz, sound is called infrasound: it is felt as pressure or…
27.5 Hz
A0 – the lowest key on a standard 88-key piano.
40 Hz
Researchers are studying 40 Hz light-and-sound stimulation (gamma rhythm) for Alzheimer's disease. Early results in mice and…
41.2 Hz
E1 – the lowest open string of a standard four-string bass guitar.
50 Hz
The mains electricity frequency in Europe, most of Asia, Africa and Australia. Transformer 'hum' is mostly at twice this, 100…
55 Hz
A1 – the lowest A on a 4-string bass and an octave above the piano's lowest A.
60 Hz
The mains frequency in North America, parts of South America, Korea, Taiwan and western Japan. Hum from these grids sits at 60…
82 Hz
Very close to E2 (82.41 Hz), the lowest open string of a guitar in standard tuning.
100 Hz
Twice the 50 Hz mains frequency – the dominant pitch of transformer and fluorescent-ballast hum in 50 Hz countries.
110 Hz
A2 – the open fifth string (A) of a guitar.
120 Hz
Twice the 60 Hz mains frequency – the familiar electrical hum in North America.
174 Hz
Part of the so-called 'Solfeggio frequencies' used in meditation music. There is no scientific evidence that these specific…
196 Hz
G3 – the lowest open string of the violin.
256 Hz
'Scientific pitch' sets middle C to exactly 256 Hz (a power of two), which puts A4 near 430.5 Hz. It was used in physics and…
261.63 Hz
Middle C (C4) in standard A440 tuning.
285 Hz
One of the so-called 'Solfeggio frequencies'. Claims about its effects are not supported by scientific evidence.
300 Hz
The lower edge of the classic telephone voice band (300–3,400 Hz). Your voice's fundamental is often below it – your brain fills…
350 Hz
Together with 440 Hz, forms the North American telephone dial tone.
396 Hz
One of the so-called 'Solfeggio frequencies'. Claims about its effects are not supported by scientific evidence.
400 Hz
Aircraft electrical systems run at 400 Hz, allowing lighter transformers and motors – the source of the whine in many cockpits.
417 Hz
One of the so-called 'Solfeggio frequencies'. Claims about its effects are not supported by scientific evidence.
425 Hz
The dial-tone frequency used across much of Europe.
432 Hz
A popular alternative tuning (A4 = 432 Hz), sometimes called 'Verdi's A'. Claims that it is more 'natural' or healing are not…
440 Hz
A4, the international standard concert pitch (ISO 16). Orchestras tune to it – or slightly higher, 442–443 Hz, in much of Europe.
520 Hz
Smoke alarms in sleeping areas for people with hearing loss use a 520 Hz low-frequency square-wave signal, which wakes sleepers…
528 Hz
Marketed as the 'love' or 'DNA repair' frequency in the Solfeggio set. There is no scientific evidence for these claims.
639 Hz
One of the so-called 'Solfeggio frequencies'. Claims about its effects are not supported by scientific evidence.
697 Hz
The lowest 'row' tone of DTMF touch-tone dialling (keys 1, 2, 3). Each key sends a row tone and a column tone together.
741 Hz
One of the so-called 'Solfeggio frequencies'. Claims about its effects are not supported by scientific evidence.
770 Hz
DTMF row tone for keys 4, 5, 6.
852 Hz
DTMF row tone for keys 7, 8, 9 – and also one of the so-called 'Solfeggio frequencies'.
941 Hz
DTMF row tone for keys *, 0, #.
963 Hz
The highest of the so-called 'Solfeggio frequencies'. Claims about its effects are not supported by scientific evidence.
1,000 Hz
The reference frequency of acoustics: decibel scales, equal-loudness contours and many audio measurements are anchored at 1 kHz…
1,209 Hz
DTMF column tone for keys 1, 4, 7 and *.
1,336 Hz
DTMF column tone for keys 2, 5, 8 and 0.
1,477 Hz
DTMF column tone for keys 3, 6, 9 and #.
1,633 Hz
DTMF column tone for the rarely seen A, B, C, D keys used in military and amateur radio systems.
2,600 Hz
The supervisory tone of the old Bell System long-distance network. 'Phone phreaks' discovered they could seize trunk lines with…
3,000 Hz
Close to the resonance of the human ear canal (about 2.5–3.5 kHz). The ear is most sensitive between roughly 2 and 5 kHz – which…
3,400 Hz
The upper edge of the classic telephone voice band. HD voice and VoIP codecs extend this to 7 kHz or more.
4,000 Hz
Noise-induced hearing loss typically shows up first as a dip around 4 kHz on an audiogram – the so-called 'noise notch'.
4,186 Hz
C8 – the highest key on a standard 88-key piano.
8,000 Hz
The top of a standard clinical hearing test (250–8,000 Hz). Sibilant 's' sounds carry energy from about 4 to 10 kHz.
15,625 Hz
The line frequency of PAL/SECAM tube televisions – the whine many people remember hearing from old CRT TVs.
15,734 Hz
The horizontal scan frequency of NTSC colour CRT televisions (15.734 kHz) – the high-pitched whine of old TVs in North America…
17,400 Hz
Used by the 'Mosquito' anti-loitering device and by teenage 'mosquito ringtones', because most adults over about 25 can no…
20,000 Hz
The conventional upper limit of human hearing. Most adults lose sensitivity above 15–17 kHz with age; above 20 kHz is ultrasound.
22,050 Hz
Half of the CD sample rate (44.1 kHz) – the Nyquist frequency, the highest frequency a CD can represent.
24,000 Hz
Half of the 48 kHz sample rate used for video and broadcast audio – its Nyquist frequency.
25,000 Hz
Ultrasound used by some pest repellers and dog whistles. Dogs, cats and rodents can hear it; humans cannot.
32,768 Hz
The frequency of the quartz crystal in almost every watch and clock: 2¹⁵ Hz, which halves neatly down to one tick per second.
40,000 Hz
The standard frequency of ultrasonic parking sensors and hobby rangefinders – and a common frequency for ultrasonic cleaning…

Infrasound (1–19 Hz)

Bass & sub-bass (20–250 Hz)

Midrange (250–2,000 Hz)

Upper range (2–10 kHz)

High frequencies (10–20 kHz)

Ultrasound (above 20 kHz)

Frequently asked questions

What frequency range can humans hear?

Roughly 20 Hz to 20,000 Hz for young people with healthy ears. The upper limit drops with age – many adults over 40 cannot hear above 14–16 kHz.

What is the most sensitive frequency for human hearing?

Between about 2,000 and 5,000 Hz, helped by the resonance of the ear canal near 3 kHz.

What is the difference between frequency and pitch?

Frequency is a physical measurement in hertz; pitch is how we perceive it. Pitch roughly follows the logarithm of frequency, so each doubling sounds like the same step – an octave.