decibel
Học thuậtThân thiện
Definition
- Noun:
- A unit for measuring the relative intensity of sound: The decibel is a logarithmic unit used to express the ratio between two values of a physical quantity, most commonly sound pressure level or power. It indicates how loud a sound is relative to a reference level.
- A unit for measuring ratios of power or amplitude in electronics and acoustics: While most commonly associated with sound, the decibel is a general unit for expressing ratios, such as signal gain or loss.
Usage Examples
- Noun:
Advanced Usage
- "Decibel level": A common phrase referring to the measured intensity of sound.
- Used in comparative expressions: Decibels are inherently comparative, measuring one intensity against a standard reference.
Variants and Related Words
- dB: The standard abbreviation for decibel.
- Bel: The larger unit from which the decibel is derived; one decibel is one-tenth of a bel. This term is rarely used in practice.
Synonyms
- Sound level unit: A more general descriptive term.
- dB (abbreviation): The direct abbreviated form.
Notes on Meaning
- Not an absolute unit: A decibel is not a fixed amount like a meter or a kilogram. It is a logarithmic ratio. A 10-decibel increase represents a tenfold increase in sound intensity, while a 20-decibel increase represents a hundredfold increase.
- Reference intensity: For sound in air, the common reference is the quietest sound the average human ear can hear, which is defined as 0 decibels.
Noun
- a logarithmic unit of sound intensity; 10 times the logarithm of the ratio of the sound intensity to some reference intensity