High performance loudspeaker system

A loudspeaker assembly comprising:

• a first and a second speaker being mounted together coaxially,
• the first speaker having a pole piece, a former and a cone and means sealing a rear face of the cone, the sealing means having an inner surface portion profiled to conform substantially with a rear profile of the cone so as to be spaced from the cone by a distance less than that which would permit resonance therebetween at an upper limit of the operating frequency of the first speaker while permitting extension of the cone at the lower limit of the operating frequency of the first speaker;
• and
• phase plug means having a front to rear axis of symmetry and mounted in front of the pole piece to extend coaxially therewith, the phase plug means cooperating with a wall of the former and the cone to define an annular duct with an expansion ratio extending substantially from the pole piece to the base of the cone into the ambient while being spaced from the cone by a distance less than that which would permit resonance therebetween at an upper limit of the operating frequency of the first speaker while permitting extension of the cone at the lower limit of the operating frequency of the first speaker, the phase plug means having a forwardly opening socket and the second speaker being mounted in the socket.

A high performance loudspeaker system comprising:

• a housing;
• and
• four speakers mounted in the housing so as to provide a common direction of sound projection into the ambient and having respective speaker axes on a common plane,
• the housing comprising wall portions of a horn;
• a first and a second of the speakers being identical and having respective cones with front faces mounted in opposition on said wall portions;
• and, a third and a fourth of the speakers being mounted together coaxially, forming a speaker assembly, and the speaker assembly being mounted to the housing medially spanning the horn mouth in loading relation with front faces of the first and second speakers and cooperating with the wall portions to provide two, separate, horn mouth portions having areas at least equal to the areas of the cones of the first and second speakers and being aligned on respective opposite sides of and perpendicular to the common plane and in communication with both first and second speakers;
• the third speaker being of equivalent size to the first and second speakers and having a pole piece, a former and a cone and means sealing a rear face of the cone against a front pressure wave generated by the first and second speakers, the sealing means having an inner surface portion profiled to conform substantially with a rear profile of the cone so as to be spaced from the cone by a distance less than that which would permit resonance therebetween at an upper limit of the operating frequency of the third speaker while permitting extension of the cone at the lower limit of an operating frequency of the third speaker;
• the first and second speakers being operational over a low-mid frequency range, the third speaker being operational over a high-mid frequency range and the fourth speaker being operational over a high frequency range so that a range of approximately 150 Hz-5 kHz can be reproduced at a high performance level with only a single crossover point between speakers of substantially equivalent size and type.