The pitch at which a speaker driver naturally “wants” to vibrate. It sets the lowest note that driver can play cleanly.
Every driver has a natural resonant point — like a tuning fork, it vibrates most freely at one frequency. Below Fs, the driver has to work much harder to move air, and output drops off quickly.
Fs is one of the main numbers enclosure designers use to pick box volume and tuning frequency. A driver with a low Fs is generally a better candidate for deep bass in a sealed or ported box; a high-Fs driver is better suited to midrange duty.
| Context | Typical Home Audio | Typical Car Audio |
|---|---|---|
| Typical range | 20 – 50 Hz (subwoofers) | 28 – 45 Hz (subwoofers) |
| Midrange drivers | 70 – 120 Hz | 80 – 150 Hz |
