Woofer excursion limits constrain dynamic range more than tweeter capabilities do
Evidence
Obviously, the loudspeakers should be able to radiate the necessary sound power into the listening room without audible distortion or power compression. As has been stated, audible distortion in well-designed loudspeakers is not normally an audible problem until they are driven to their limits. If that happens, distortion products are generated as the diaphragms are unable to move through the required excursions in a linear manner. Woofers are a common limiting factor as they reach their excursion limits at very low frequencies. When this happens, it affects all frequencies radiated by the woofer, and the effects can be quite audible and unpleasant, especially in smaller systems where the transducer is a woofer/midrange, performing all duties up to the tweeter crossover. This is where bass management and a subwoofer are a huge benefit, allowing the system to play louder, increasing its usable dynamic range.
— Toole, Floyd E, Sound reproduction- the acoustics and…, 998
Categorization
DEFINE: Clarifies the mechanism behind power compression and distortion onset at high levels.