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US 7,454,030 B2Granted
Subwoofer with cascaded linear array of drivers
OwnerCurtis H. Graberinventor
Life of this patent
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Abstract
A single folded, expanding horn loudspeaker reproduces low frequency audible sound at high power output levels. A compact enclosure houses a plurality of identical transducers, characterized by small vibrational surface areas. The throats for each transducer into the horn are acoustically differentially spaced from the mouth of the horn. Transducer drive circuitry adjusts a drive signal for the transducers to compensate for the different impedance and propagation time to the horn mouth at each throat.
Claims12
A loudspeaker comprising:
- an enclosure including a folded horn having a base end and a mouth;
- a summing throat forming a portion of the folded horn including the base end, the summing throat increasing in cross sectional area in a direction of acoustic energy propagation;
- a plurality of acoustic transducers housed in the enclosure;
- a plurality of radiating ports, each radiating port providing for coupling sound energy from each respective acoustic transducer into the summing throat, each radiating port being disposed at a discrete, acoustically spaced location along the summing throat with successive locations of the radiating ports occurring at points along the summing throat exhibiting increasing cross sectional area to initiate and synchronously reinforce an acoustic pressure wave building from the base end toward the mouth;
- a source of an acoustic range signal;
- transducer drive signal processing circuitry having an individual channel for each of the audio transducers, the individual channels each being coupled to receive the acoustic range signal and each channel including means for setting a relative phase angle for the acoustic range signal in a channel as a function of the acoustic spacing of the radiating outlets to build an acoustic pressure wave in a cascade in the summing throat toward the mouth;
- a plurality of high pressure chambers, at least one acoustic transducer being positioned to direct sound energy into each high pressure chamber, and each high pressure chamber being connected by one of the plurality of radiating ports to the summing throat;
- and
- each radiating port terminating along a side of the summing throat at successive locations progressing from the base end of the summing throat toward the mouth of the folded horn with a direction of sound propagation transverse to the direction of sound propagation in the summing throat.
6 more elements
A loudspeaker unit comprising:
- a plurality of low frequency acoustic transducers;
- a plurality of pre-load chambers, at least one pre-load chamber being associated with each of the plurality of low frequency acoustic transducers;
- each low frequency acoustic transducer being disposed to radiate into its associated pre-load chamber;
- a horn having a base end and a mouth and formed at least in part by a surface extending from the base end to the mouth;
- and
- a plurality of ports connecting the plurality of pre-load chambers into the horn, each of the plurality of ports having a radiating opening on the surface of the horn, the radiating openings being disposed along the surface extending in line from adjacent the base end toward the mouth substantially parallel to the direction of sound propagation in the horn to support cascade formation of pressure waves from the base end toward the mouth, and with the radiating openings being oriented to direct sound into the horn locally substantially transverse with respect to an axis of sound propagation defined by the horn.
3 more elements
Dependencies are inferred from the claim text.