Sound wavelength calculator
How long is a 60 Hz wave? Enter a frequency (or a length) and get the wavelength, half and quarter.
Wavelength
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Half wavelength
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Quarter wavelength
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Speed of sound
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How it works
wavelength = speed of sound ÷ frequency
At 68 °F (20 °C) sound travels about 1,126 ft/s (343 m/s). A 60 Hz wave is about 18.8 ft (5.7 m) long, and a 10 kHz wave is about 1.4 in (3.4 cm). That range, a factor of a thousand, is why low and high frequencies behave so differently in a room.
Common frequencies at 68 °F
| Frequency | Wavelength | Quarter wave |
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Field notes
- Quarter wavelengths explain bass trap depth. Porous absorbers work best where air moves fastest, a quarter wavelength from a wall. That's why thin panels do little for bass.
- Subwoofer spacing. Subs closer together than about a quarter wavelength at their crossover add together like one bigger source. Spread them further and they start to interfere, with lobes and nulls across the room.
- Boundary effects. A speaker near a wall gets a dip at the frequency where the round trip to the wall is half a wavelength. Moving the speaker shifts the dip.
- Mic placement. Moving a mic a few inches changes nothing in the bass but a lot in the treble, because a few inches is a big fraction of a high-frequency wavelength.