Sound Wavelength
Wavelength λ = c/f where c is speed of sound and f is frequency. In air at 20°C, c ≈ 343 m/s. Audible range 20 Hz–20 kHz corresponds to 17 m–17 mm.
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20 Hz wavelength in air is 17 m; 20 kHz is 17 mm. Room modes cause peaks and nulls; dimensions determine modal frequencies. Musical note A4 = 440 Hz; wavelength in air ≈ 78 cm. Underwater sound travels ~4.5× faster than in air.
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Why: Wavelength determines room modes, diffraction, and absorption. Quarter-wavelength rule: absorbers effective when thickness ~λ/4. Musical intervals relate to frequency ratios.
How: λ = c/f. Speed of sound: air c ≈ 331 + 0.6T°C m/s; water ~1500 m/s; steel ~5000 m/s. Room modes: f = (c/2)(nx/Lx + ny/Ly + nz/Lz).
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🔧 Calculation Mode
📊 Parameters
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For educational and informational purposes only. Verify with a qualified professional.
🔬 Physics Facts
λ = c/f applies to all waves; sound, light, water waves.
— Wave Mechanics
Equal temperament: each semitone is 2^(1/12) frequency ratio.
— Musical Acoustics
Room modes create standing waves; first mode at half-wavelength = room dimension.
— Room Acoustics
k = 2π/λ is wave number; ω = 2πf is angular frequency.
— Wave Theory
What is Sound Wavelength?
Sound wavelength (λ) is the physical distance between consecutive compressions or rarefactions in a sound wave. It's inversely related to frequency: higher frequencies have shorter wavelengths. In air at 20°C, audible sounds range from about 17 meters (20 Hz) to 17 millimeters (20 kHz).
Wave Equation
λ = c / f links wavelength to speed and frequency.
Speed Varies
Sound travels ~343 m/s in air, ~1500 m/s in water, ~6000 m/s in steel.
Room Acoustics
Room modes occur at frequencies where wavelength relates to room dimensions.
Speed of Sound in Common Materials
| Material | Speed (m/s) | Category |
|---|---|---|
| Air (20°C) | 343 | Gas |
| Air (0°C) | 331 | Gas |
| Air (25°C) | 346 | Gas |
| Air (40°C) | 355 | Gas |
| Helium | 1014 | Gas |
| Hydrogen | 1284 | Gas |
| Carbon Dioxide | 267 | Gas |
| Oxygen | 326 | Gas |
| Water (fresh, 20°C) | 1481 | Liquid |
| Water (fresh, 25°C) | 1497 | Liquid |
❓ Frequently Asked Questions
What is the relationship between wavelength and frequency?
Wavelength and frequency are inversely proportional: λ = c / f, where λ is wavelength, c is speed of sound, and f is frequency. Higher frequencies have shorter wavelengths, and vice versa.
How does the speed of sound vary in different media?
Sound travels fastest in solids (~6000 m/s in steel), slower in liquids (~1500 m/s in water), and slowest in gases (~343 m/s in air). Speed depends on material density and elastic properties.
What frequency range can humans hear?
The human hearing range is typically 20 Hz to 20,000 Hz (20 kHz). Frequencies below 20 Hz are infrasonic, and above 20 kHz are ultrasonic.
How do room dimensions affect sound waves?
Room modes occur when sound wavelengths match room dimensions. Axial modes occur at frequencies f = nc / 2L, where n is the mode number, c is speed of sound, and L is room dimension.
Why does sound travel faster in water than air?
Water is denser and has higher bulk modulus (stiffness) than air. The speed of sound is proportional to √(bulk modulus / density), so denser, stiffer materials transmit sound faster.
What is the difference between wavelength and period?
Wavelength (λ) is the spatial distance between wave peaks, measured in meters. Period (T) is the temporal time between peaks, measured in seconds. They're related by λ = c × T.
How does temperature affect the speed of sound?
In air, speed increases with temperature: c ≈ 331.3 + 0.606T (T in °C). Warmer air molecules move faster, increasing sound propagation speed by approximately 0.6 m/s per °C.
What are wave number and angular frequency?
Wave number (k = 2π/λ) represents spatial frequency in radians per meter. Angular frequency (ω = 2πf) represents temporal frequency in radians per second. Both describe wave properties mathematically.
📚 Official Data Sources
⚠️ Disclaimer
This calculator is for educational and design purposes. Speed of sound values are approximations and vary with temperature, pressure, humidity, and material composition. For critical applications in acoustics, audio engineering, or medical ultrasound, consult professional acousticians or engineers. Actual measurements may differ from calculated values.
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