Abstract: A vent for linear control of pressure in an infinite baffle type loudspeaker system wherein an elongated "V" shaped trough is cut through the back wall of a speaker enclosure with the smaller side of the trough piercing the inner surface of the back wall of the enclosure and the larger side thereof piercing the outer surface thereof. Outside the outer wall, the trough is covered by a dispersion structure including a plurality of transverse plates generally at right angles thereto whose back edges are covered so that air flow into and out of the cabinet must pass through channels formed by the back wall of the enclosure, the plates and the cover.

Abstract: A loudspeaker cabinet system wherein at least two low frequency drivers of equal effective diameters are critically spaced a vertical distance which equals the effective piston diameter of one driver times .pi.. When so placed, the respective spherical wave fronts of the drivers interfere causing a composite elliptical wave front which being flatter than the spheric can reflect from walls without drastically changing its shape to produce a uniform field which reaches the listener without producing any areas of the room which appear acoustically dead. Such system is especially useful in small rooms having reflective wall surfaces. Once the low frequency drivers are critically spaced and aligned, a higher frequency speaker or array of higher frequency speakers can be positioned thereabout without destroying the quality thereof.