Maximum output of an electronic device or recording medium compared to its noise floor or level of background noise. S/N ratios are measure in decibels (dB), and larger numbers are better. A S/N ratio of 100 dB means that the maximum signal output is 100 decibels above the noise floor, or the point at which the signal will be obscured by noise (low-level hum and other electrical interference that is part of the component). igital media such as CDs and DVDs tend to have higher signal-to-noise ratios than analog media such as VHS tapes and audiocassettes. Solid state amplifiers (those based on transistors instead of vacuum tubes) tend to have high signal-to-noise ratios. When comparing audio/video components, a higher S/N ratio is better (of course the difference between a high 100 dB number and a 105 dB is not a deciding factor as both figures are excellent and will cause no problems in ordinary listening).