Seal leakage makes closed-back headphone bass highly listener-dependent.

Evidence

As expected, the variance in response is much higher for closed back headphones compared to open backs with one exception illustrated with an arrow. This closed-back model (DCA Aeon Noire) has reproducibility below 200 Hz that is almost as good as open backs. Not shown in this data is the distribution of responses measured across the 15 listeners for closed-back models. For some listeners the headphone seals well and produces excellent bass, and for other listeners it leaks and produces little or no bass. Because the headphone cannot consistently deliver the same signals to all the listeners, the quality of listening experiences will vary, as will their opinions of how good the headphone sounds. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1748

Categorization

• XREF: Connects to headphone-equalization research and the practical difficulty of personalizing headphones to individual ear/head geometry.
• SHARE: Send to an audiophile friend who insists a closed-back model sounds different between people; the seal-leak mechanism is exactly the explanation.