Nice set of original BOSE 901s. I dont have the equalizer but they still sound fantastic. Depending on one’s viewpoint, the Bose 901 speaker system might be considered a revolutionary approach to sound reproduction, or simply a workable combination of well-established (and sometimes deprecated) techniques. The Bose 901 enclosures house nine small, specially designed drivers that have 4-inch cones and powerful magnetic structures. Eight of the drivers are angled to the rear, while the ninth is mounted on the front of the enclosure facing the listening area. This arrangement is intended to achieve approximately the same ratio of direct to reflected sound that exists in the concert hall. The 901’s cabinets are quite compact, measuring 12-3/4 inches high by 20-9/16 inches wide when viewed from the front. Seen from the top, the rear of the enclosure forms a “V” of about 120 degrees. Basic to its operation is the requirement that it be mounted with the “V” facing the wall, the apex being about 12 inches from the wall. When a pair of 901s are so installed, the sound appears to be uniformly distributed across the wall between the speakers completely free of any “hole-in-the-middle” effect. Since only 11 percent of the sound is radiated directly forward, it is almost impossible to localize the source.