Sound Converter

By KAMP Inc. / UnitOwl · Last reviewed: April 3, 2026

Sound level measurement uses the decibel scale — a logarithmic unit that compresses the enormous range of human hearing into a manageable scale. From the threshold of hearing at 0 dB to a rocket launch at 180+ dB, each increase of 10 dB represents a tenfold increase in acoustic intensity. This logarithmic nature means that understanding decibels requires moving beyond simple arithmetic, but it also makes describing the full range of human-perceptible sounds practical.

Amount

From

Result

10 dB

1 B = 10 dB

Popular Sound Conversions

Decibels to Nepers Nepers to Decibels Decibels to Bels Bels to Decibels Nepers to Bels Decibels to Millibels

The Decibel Scale: Logarithmic, Not Linear

The decibel (dB) expresses a ratio, not an absolute quantity. For sound pressure level (SPL), dB = 20 × log₁₀(P / P₀), where P₀ is the reference pressure of 20 μPa — the approximate threshold of human hearing. Because it is logarithmic: +3 dB represents roughly double the acoustic power; +6 dB doubles the sound pressure; +10 dB is perceived as approximately twice as loud by the human ear. Conversely, -10 dB sounds about half as loud. Normal conversation occurs around 60 dB; a lawnmower at 1 meter is about 90 dB; a jet engine at 30 meters produces about 140 dB. Prolonged exposure above 85 dB causes hearing damage; sounds above 120 dB cause immediate pain.

Source	Sound Level
Threshold of hearing	0 dB SPL
Quiet whisper	30 dB
Normal conversation	60 dB
Heavy traffic	85 dB
Live concert (front row)	110–120 dB
Jet engine (30 m)	~140 dB

Decibels in Audio Engineering and Electronics

In audio electronics, dB is used as a relative measure of gain or attenuation. Voltage gain in dB = 20 × log₁₀(Vout / Vin); power gain in dB = 10 × log₁₀(Pout / Pin). An amplifier with a gain of 20 dB amplifies voltage by 10× (power by 100×). Standard reference levels include dBu (reference 0.7746 V RMS, used in professional audio), dBV (reference 1 V RMS), and dBm (reference 1 mW into 600 Ω, used in telecommunications). Noise floors in high-quality microphone preamps are typically −130 to −120 dBu; headphone amplifiers aim for < −100 dBu THD+N. Understanding which reference a spec sheet uses prevents misinterpreting equipment comparisons.

Sound Speed and Frequency

The speed of sound in air at 20°C (68°F) is approximately 343 m/s (1,125 ft/s or 767 mph). It varies with temperature: roughly +0.6 m/s per °C. At 0°C, the speed is about 331 m/s; at 35°C, about 352 m/s. Speed of sound in water is approximately 1,480 m/s — over 4× faster than in air, which is why sonar is effective underwater. The relationship between speed, frequency, and wavelength: wavelength = speed / frequency. A 100 Hz bass note in air has a wavelength of 343 / 100 = 3.43 meters; a 10 kHz treble note has a wavelength of 3.43 cm. This is why bass frequencies require large speakers and room dimensions for proper reproduction.

Sources & References

NIST — Units and Conversion Factors — Official unit conversion factors from the National Institute of Standards and Technology.
BIPM — The International System of Units (SI) — International SI unit definitions from the International Bureau of Weights and Measures.