Smoother, flatter, wider-bandwidth on-axis curves predict higher subjective loudspeaker ratings.

Evidence

By the early 1980s I had created a digitally controlled, 360° data acquisition system with data post processing, calibrated the anechoic chamber to low frequencies, and had accumulated enough subjective and objective data to publish two major papers in JAES (Toole, 1985, 1986). Figure 2.4 shows results from the author’s early investigations. They show anechoic loudspeaker measurements organized according to subjective sound quality ratings. There is no doubt that there is a relationship between the visible characteristics of the measured curves and the subjective “fidelity” ratings. The trends in the families of curves are visually evident: smoother, flatter, wider-bandwidth on-axis curves are associated with higher subjective ratings. Good performance at angles well off axis appear to be a positive contributing factor. Consistent features in the family of curves were indicators of resonances, low bass extension was an observable advantage, and so on. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1198