Patent ID: 9549242
Date: 2017-01-17
CPC Classifications: H04R

Claim:
1. A loudspeaker comprising: an enclosure; a driver element located within the enclosure and comprising a cone diaphragm; a first cavity, defined by a first cavity wall and the cone diaphragm, the first cavity extending from the cone diaphragm and having a first opening which has an area less than an area of the cone diaphragm; an exit element extending from the first opening of the first cavity and acoustically coupling the first cavity to an environment outside of the enclosure; a second cavity, defined by a second cavity wall within the enclosure extending from a second opening in the first cavity; an acoustic element in the second opening acoustically coupling the second cavity to the first cavity, the second cavity not otherwise being acoustically coupled to the environment outside of the enclosure; wherein the first cavity and the exit element in combination have a first acoustic impedance, and resonances occur in the first cavity at first frequencies; the second cavity and the acoustic element together have a second acoustic impedance; at the first frequencies, the second acoustic impedance is dominated by resistance and is less than the first acoustic impedance; and at frequencies other than the first frequencies, where resonances do not occur in the first cavity, the second acoustic impedance is greater than the first acoustic impedance.