signal-to-noise ratio
The decibel difference between the level of a target signal (typically speech) and the level of background noise, used to quantify the listening difficulty of a given acoustic environment.
Full Definition
In audiology, signal-to-noise ratio (SNR) is the difference in decibels between the intensity of the speech signal and the intensity of competing noise. A positive SNR (signal louder than noise) is generally easier to understand, while a negative SNR is more challenging. SNR is a central metric in speech-in-noise testing, hearing aid benefit assessment, and classroom acoustics standards. Editors should note that SNR is expressed as a dB value, not a percentage, and should use a hyphen in the adjectival form ('signal-to-noise ratio' or 'SNR loss') consistently.
Usage
Usage note: Hyphenate the full term consistently as 'signal-to-noise ratio'. Express as a decibel value (e.g., +5 dB SNR), not as a percentage or ratio. 'SNR loss' is a specific test metric, not a synonym for SNR.
In Context
- "The classroom's signal-to-noise ratio was measured at –5 dB, well below the recommended +15 dB for listeners with hearing loss." — School acoustics audit report
- "At a +5 dB SNR, the child correctly repeated 72% of target sentences." — Speech-in-noise assessment