How loud a speaker gets for a given amount of power in — and why matching it to your amp's output matters for clean sound.
Input sensitivity (often listed in volts for line-level gear, or dB for speakers) tells you how much signal a component needs to reach a reference output level. Mismatched sensitivity between a source and an amplifier is one of the most common causes of noise or distortion in a system.
If your amplifier's input sensitivity is set too low for your source's output voltage, you'll need to turn the volume up further to compensate, raising the noise floor along with it. Set too high, and you risk clipping the input stage before the volume knob ever gets turned up.
| Context | Typical Home Audio | Typical Car Audio |
|---|---|---|
| Head unit pre-out | — | 2 – 5 V |
| Line-level source | 0.5 – 2 V | 1 – 4 V |
