US 12,149,906 B2
Phase plug for compression driver
Andrea Casadei, Bagno a Ripoli (IT); Valentina Cardinali, Bagno a Ripoli (IT); and Phillip Graham, Tucker, GA (US)
Assigned to B&C SPEAKERS NA (USA), LLC, Pompton Plains, NJ (US)
Filed by B&C SPEAKERS NA (USA), LLC, Pompton Plains, NJ (US)
Filed on Nov. 14, 2023, as Appl. No. 18/389,310.
Claims priority of provisional application 63/426,482, filed on Nov. 18, 2022.
Prior Publication US 2024/0171914 A1, May 23, 2024
Int. Cl. H04R 7/12 (2006.01)
CPC H04R 7/12 (2013.01) 6 Claims
OG exemplary drawing
 
1. A phase plug for an electrodynamic compression driver, comprising:
a. a compression chamber formed by an oscillating dome-shaped diaphragm and a boundary face of a phase plug assembly adjacent to the diaphragm, the boundary face having a shape complementary to a convex surface of the diaphragm;
b. a singular acoustic exit defined by a termination of the phase plug assembly;
c. an inner acoustic passageway and an outermost acoustic passageway which each traverse through the phase plug assembly from an entrance at the compression chamber to a termination at the acoustic exit; and
d. an axis of rotation, defined within an interior of the phase plug assembly, that extends from the boundary face of the phase plug assembly at the compression chamber to the acoustic exit;
e. wherein the inner and outermost acoustic passageways expand in cross sectional area between the respective entrance at the boundary face of the phase plug assembly, and the termination at the acoustic exit, while traversing through the phase plug; and
f. wherein the inner acoustic passageway is rotated symmetrically about the axis of rotation in a manner that is spiral, conic spiral, or helical with respect to the axis of rotation;
g. wherein the outermost acoustic passageway is rotationally symmetric about the axis of rotation and is disposed radially outward of the inner acoustic passageway;
h. wherein lengths of each of the inner and outermost acoustic passageways, as defined by a total distance along a path traced by a passageway from the boundary face of the phase plug to the acoustic exit, are similar;
i. wherein the entrances of the inner and outermost acoustic passageways are disposed at modes of the compression chamber to reduce resonances of the compression chamber;
j. wherein a rate of expansion of the cross sectional area of the inner and outermost acoustic passageways is similar, so as to form respective acoustic impedances at the termination of the inner and outermost acoustic passageways where said acoustic impedances are similar; and
k. wherein the phase plug is axis-symmetric with respect to the axis of rotation.