Subjective listening remains the final authority over measurement validity.

Evidence

The practical problem is that if the frequency responses of the loudspeakers (or headphones) being compared are very different a loudness balance achieved with one kind of signal would not apply to a signal with a different spectrum. … In all these cases, if in doubt, turn the instruments off and listen; a subjective test is the final authority—it is used to test the validity of measurements. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1124

Categorization

• DEFINE: Clarifies that loudness balancing is signal-spectrum-dependent and that subjective tests verify measurements, not vice versa.