THX-certified dipole surrounds varied wildly in measured sound quality

Evidence

For completeness, let us see examples of four dipole surround loudspeakers that were designed for that sole purpose, three of which were approved by THX and for which they received a licensing fee, Figure 8.11. Little needs to be said if one attends to the bold solid black curves that describe one of many possible direct sounds from these loudspeakers; they are all unattractive and very different from each other. One wonders what the criterion for approval was. Sound quality was obviously not a consideration. — Toole, Floyd E, Sound reproduction- the acoustics and…, 828

Categorization

• CANDY: THX approved loudspeakers whose measured direct sound was ‘unattractive and very different from each other’ - certification apparently ignored sound quality.
• XREF: connects to: THX-type dipole surrounds produced irregular mid-frequency depressions, not neutral nulls — Toole, Floyd E, Sound reproduction- the acoustics and…, 827; Commercially sold dipole surrounds were not acoustically true dipoles; THX dipole surround speakers degraded direct sound while failing to create genuine diffusion. — Toole, Floyd E, Sound reproduction- the acoustics and…, 762 (+2 more)
• yield-rescued: below the book’s yield-target cutoff, included anyway for connecting to: THX-type dipole surrounds produced irregular mid-frequency depressions, not neutral nulls — Toole, Floyd E, Sound reproduction- the acoustics and…, 827; Commercially sold dipole surrounds were not acoustically true dipoles; THX dipole surround speakers degraded direct sound while failing to create genuine diffusion. — Toole, Floyd E, Sound reproduction- the acoustics and…, 762 (+2 more)