How far a speaker cone can move before it distorts or gets damaged — a key spec for how loud and low a subwoofer can go.
Xmax is the maximum linear distance (usually in millimeters) a driver's cone can travel in one direction while staying within its designed magnetic and mechanical limits. Push past it and distortion rises sharply, and sustained overexcursion can cause physical damage.
Xmax matters most at low frequencies and high output, where a driver has to move the most air to maintain volume. Two subwoofers with similar power handling can have very different real-world output capability if their Xmax figures differ significantly.
| Context | Typical Home Audio | Typical Car Audio |
|---|---|---|
| Small subwoofers (8–10″) | 5 – 9 mm | 5 – 9 mm |
| Large subwoofers (12–15″) | 10 – 20+ mm | 10 – 20+ mm |
