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.