The formula
Wavelength λ = c / f, where c is the speed of sound in the medium and f the frequency. In air at 20 °C, c ≈ 343 m/s, so a 1 kHz tone is 34.3 cm long and a 100 Hz bass note 3.43 m.
Wavelength matters in acoustics because objects only block or reflect sound well when they are larger than its wavelength – which is why bass passes through walls and around corners while treble is easily absorbed.
Frequently asked questions
What is the wavelength of 20 Hz?
About 17 m in air – the reason deep bass is so hard to control in rooms.
What is the wavelength of 20 kHz?
About 1.7 cm in air.