Abstract: New loudspeaker driver configurations comprise positioning the high frequency driver between symmetrically located lower frequency drivers and providing in combination electrical or acoustical delay to the high frequency driver relative to the lower frequency drivers. The lower frequency drivers are located above and below at equal distances from the high frequency driver or, with more than two lower frequency drivers, symmetrically about the high frequency driver. The sound pressure level and phase response is substantially equivalent to co-axial drivers including suitable high frequency electric delay circuitry operating at similar power levels. The delay for the high frequency driver is electrical or electrical in combination with a geometrical delay. With a stereo pair of loudspeakers the high frequency driver may be offset from the vertical between the above and below low frequency drivers in an outboard direction of the stereo pair.

Abstract: Disclosed is a passive delay network for insertion in the high frequency signal path of a crossover network in a high fidelity loudspeaker. The delay network provides means to adjust the optimum listening window electrically rather than by changes in the physical construction of the speaker cabinet. Electroacoustic high frequency and low frequency drivers may be mounted in a planar baffle or mounted co-axially. The delay network retains a "flat" amplitude-frequency characteristic and minimizes time dispersion in the acoustic signal received by the listener. Correction for time delay is most important near the transition frequency of the crossover network because near the transition frequency substantially equal sound energy is radiated by both the high frequency and low frequency drivers.Also disclosed is a novel construction for a co-axial driver combination and a technique for adjusting both the delay in the electric delay line network and the air path delay of electroacoustic drivers.