A single number that summarizes how a driver's suspension and motor control its motion near resonance — a key input for enclosure design.
Qts combines a driver's mechanical damping (Qms) and electrical damping (Qes) into one figure describing how sharply or broadly it resonates around its Fs. Low-Qts drivers tend to suit ported enclosures; higher-Qts drivers often work better sealed.
Qts alone doesn't tell you everything — enclosure designers also weigh Fs and Vas (effective compliance volume) together — but it's usually the first number checked when deciding what type of box will get the best result from a given driver.
| Context | Typical Home Audio | Typical Car Audio |
|---|---|---|
| Ported-friendly | < 0.4 | < 0.4 |
| Sealed-friendly | 0.4 – 0.7 | 0.4 – 0.7 |
