Dana, it may be that the the ERDs are in fact "in an entirely different class" from the QSs. They appear to be a fairly routine dipolar design, while the QSs use upward and downward in-phase firing mid-woofers(possibly inspired by Allison designs of the 1970s)which uniquely combine very wide dispersion with an element of directness to suit various source materials well.

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Enjoy the music, not the equipment.