The gap between your music and the background hiss a component produces — a higher number means quieter, cleaner playback at idle.
Signal-to-noise ratio (SNR) compares the level of the intended audio signal to the level of unwanted background noise a component generates, expressed in dB. A higher SNR means more headroom before noise becomes audible.
SNR is most noticeable during quiet passages or pauses in music, where hiss or hum would otherwise be exposed. Gain structure plays a big role here: running a head unit's volume low while an amplifier's gain is set very high (to compensate) tends to raise the noise floor relative to the music — the opposite of a clean setup.
| Context | Typical Home Audio | Typical Car Audio |
|---|---|---|
| Good | 90 – 100 dB | 80 – 95 dB |
| Excellent | > 100 dB | > 95 dB |
