Acoustic system

An enclosure for use with a speaker, the enclosure comprising in combination:

• the speaker being acoustically connected to said enclosure, for generating two sound waves, a forward sound wave, and a rearward sound wave;
• a waveguide formed at least partly within said enclosure, and acoustically connected to the speaker, for defining an acoustic path along which said rearward sound wave travels;
• said waveguide including a plurality of inner panels positioned inside said enclosure for lengthening the length of said travel path;
• said plurality of inner panels and said enclosure defining a plurality of inner passageways, and a plurality of inner openings, for causing a selective cancellation of said rearward sound wave traveling along said acoustic path at predetermined frequencies, while allowing sound waves at other frequencies to propagate with minimal attenuation;
• wherein said enclosure includes an output port through which said rearward sound traveling along said acoustic path exits;
• wherein said waveguide and said enclosure define a first compartment adjacent to the speaker;
• wherein said first compartment has a predetermined volume;
• wherein the speaker has a rear surface, at least partly enclosed within said first compartment;
• and
• wherein said volume loads the rear surface of the speaker with back pressure, in order to reduce a cone excursion of the speaker.

A method for producing sounds over a broad range of frequencies using a speaker, the method comprising the steps of:

• acoustically connecting the speaker to an enclosure for generating two sound waves, a forward sound wave, and a rearward sound wave;
• forming a waveguide including a plurality of inner panels, at least partly within said enclosure, and acoustically connecting said waveguide to speaker for defining an acoustic path along which said rearward sound wave travels;
• positioning said plurality of inner panels inside said enclosure for lengthening the length of said travel path;
• said plurality of inner panels and said enclosure defining a plurality of inner passageways, and a plurality of inner openings, for causing a selective cancellation of said rearward sound wave traveling along said acoustic path at predetermined frequencies, while allowing sound waves at other frequencies to propagate with minimal attenuation;
• wherein said enclosure includes an output port through which said rearward sound traveling along said acoustic path exits;
• wherein the speaker has a piston area S.sub.D ;
• wherein the surface area of said output port is equal to a portion of said piston area S.sub.D ;
• wherein said waveguide and said enclosure define a first compartment adjacent to the speaker;
• wherein said first compartment has a predetermined volume;
• wherein the speaker has a rear surface, at least partly enclosed within said first compartment;
• and
• wherein said volume loads said rear surface of the speaker with back pressure, in order to reduce a cone excursion of the speaker.