Open-back headphones deliver the most consistent response across listeners.

Evidence

On the other hand, open-back models have a built-in leak, and with good design can deliver the most consistent frequency response across the widest range of listeners. This makes them excellent candidates for psychoacoustic experiments where the goal is to deliver the same signals to each listener so that the results are reproducible and traceable to headphone measurements made on test fixtures. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1749

Categorization

• XREF: The built-in leak rationale parallels how controlled acoustic leaks stabilize bass for open-back designs across variation in seal quality.