Highly regarded hifi loudspeakers had wildly non-flat anechoic responses

Evidence

Technically accurate loudspeakers were needed to deliver the contrived test sounds, so I measured the performance of the loudspeakers that were present in the lab, an Acoustic Research AR-3 and a Tannoy Cadet. What was found was disconcerting. The measured anechoic on-axis frequency responses were far from flat and very different from one another. At the time the AR3 was a highly respected loudspeaker, so there was the question of how such a non-flat performance could sound good. All electronics, then and now, aimed for a flat frequency response over the audible frequency range so as not to modify the recorded sounds. Why should loudspeakers be different? — Toole, Floyd E, Sound reproduction- the acoustics and…, 66

Categorization

• SEED: The puzzle of why loudspeakers could historically get away with non-flat responses while electronics could not is a good essay angle on measurement vs. perception in audio.