Simple Explanation

The difference between the level of the desired signal and the level of background noise. A higher SNR indicates a clearer, better-quality signal.

Concise Technical Definition

SNR (Signal to Noise Ratio) is a measurement of the difference between the signal level (or power) and the noise level (or power) in an audio system. It is typically expressed in decibels (dB), with a higher SNR indicating less noise and a clearer signal. This ratio is important for evaluating the quality of an audio system, as a higher SNR means the signal is stronger relative to the background noise. The reference level (e.g., +4 dBu for professional audio) and the noise measurement conditions (such as bandwidth and weighting filters) must be specified for an SNR value to be meaningful.

Layman-Friendly Analogy

Think of it like listening to music with the sound of static in the background. A high SNR is like listening to your favorite song with very little static, while a low SNR means the music is harder to hear because there’s a lot of static or background noise.

Industry Usage Summary

SNR is a key parameter in evaluating the quality of audio systems, especially in recording studios, sound reinforcement, and broadcasting. It is used to assess how much usable signal is present in comparison to unwanted noise, which is critical for maintaining clarity in professional audio equipment. A higher SNR means that the device is more capable of producing a clean and undistorted signal. The SNR is commonly cited in specifications for microphones, audio interfaces, amplifiers, and other equipment, though it is essential to consider the full context of the measurement, including reference levels, bandwidth, and filtering methods.

Engineering Shortcut

The ratio of the signal level to the noise level, typically expressed in decibels (dB).

Full Technical Explanation

SNR (Signal to Noise Ratio) is an audio measurement that compares the level of the desired signal to the level of unwanted noise in the system. It is expressed as a ratio of signal power to noise power, usually in decibels (dB). To measure SNR accurately, the reference signal level must be specified, which is typically either the nominal operating level (e.g., +4 dBu for professional audio) or the maximum output level (around +20 dBu). The noise level is measured using a true RMS voltmeter over a specified bandwidth, and weighting filters may be applied in some cases. For an SNR value to be meaningful, all these parameters must be clearly stated, as a generic number (e.g., "SNR of 90 dB") lacks context without the necessary details. The highest possible SNR is referred to as the system's dynamic range, which is the difference between the loudest and softest signals the system can process without distortion.