Start with your device volume low. Very low tones may be inaudible on phone or laptop speakers; very high tones can be uncomfortable on headphones.
What does 9 Hz sound like?
9 Hz is a infrasound frequency. It is infrasound – below the roughly 20 Hz lower limit of human pitch perception. At high levels it is felt as pressure, fluttering or vibration rather than heard as a tone, and phone or laptop speakers cannot reproduce it at all.
A 9 Hz sound wave completes 9 cycles every second, so one cycle lasts 111 ms. In air at 20 °C, where sound travels at about 343 m/s, each wave is 38.11 m (125.04 ft) long; in water it stretches to 164.56 m because sound moves about 4.3 times faster there.
Natural infrasound comes from earthquakes, volcanoes, ocean waves, wind and thunder; whales and elephants use it to communicate across long distances.
Wavelength of 9 Hz in different materials
| Medium | Speed of sound | Wavelength |
|---|---|---|
| Air (20 °C) | 343 m/s | 38.11 m |
| Fresh water | 1,481 m/s | 164.56 m |
| Seawater | 1,500 m/s | 166.67 m |
| Helium | 1,007 m/s | 111.89 m |
| Steel | 5,960 m/s | 662.22 m |
| Glass | 5,640 m/s | 626.67 m |
Harmonics and octaves
Real instruments playing 9 Hz also produce harmonics at whole-number multiples of the fundamental. Their relative strength gives each instrument its timbre.
Which animals can hear 9 Hz?
Can hear it
None of the animals in our list.
Cannot hear it
Humans, Dogs, Cats, Horses, Cows, Sheep, Pigs, Goats, Rabbits, Rats, Mice, Gerbils, Guinea pigs, Hedgehogs, Raccoons, Ferrets, Opossums, Chinchillas, Bats, Elephants, Beluga whales, Bottlenose dolphins, Chickens, Canaries, Budgerigars (parakeets), Cockatiels, Owls, Bullfrogs, Tree frogs, Goldfish, Catfish, Tuna, Greater wax moths
Frequently asked questions
What does 9 Hz sound like?
It is infrasound – below the roughly 20 Hz lower limit of human pitch perception. At high levels it is felt as pressure, fluttering or vibration rather than heard as a tone, and phone or laptop speakers cannot reproduce it at all.
Can humans hear 9 Hz?
No. 9 Hz is below the ~20 Hz limit of human pitch perception; very loud infrasound can be felt as vibration.
What musical note is 9 Hz?
9 Hz is 34 cents below D-1, which is 9.18 Hz in standard A440 tuning.
What is the wavelength of 9 Hz?
About 38.11 m in air at 20 °C and 164.56 m in water.
Can dogs hear 9 Hz?
No – dogs hear roughly 67 Hz to 45,000 Hz.