Patent ID: 6834113
Filing Date: 2004-12-21
Classification: H04R

Abstract:
A loudspeaker system for creating a homogenous sound over large distances with a wide horizontal distribution comprising:at least one line-source of acoustical radiation, each of said at least one line-source comprising three or more essentially identical speaker-units arranged adjacent to each other at a center-to-center spacing D1, and at least one elongated high frequency transducer arranged in parallel with said at least one line source, said at least one elongated high frequency transducer having an essentially continuous radiating surface along an axis of elongation; an input electrical audio signal divided into two parts at a crossover frequency FCR with an attenuation of at least 18 dB/octave; wherein a first part of said two parts comprise frequencies lower than said crossover frequency FCR; wherein a second part of said two parts comprise frequencies higher than said crossover frequency FCR; wherein the first part is fed to said at least one line-source of acoustical radiation and the second part is fed to said at least one elongated high frequency transducers(s); wherein a highest possible crossover frequency FMAX(FCR&lE;FMAX) for said speaker units in said at least one line-source of acoustical radiation is determined as a frequency which is at least one octave lower than a frequency FDEV; wherein said frequency FDEV is a frequency at which at least one of neither of a speaker response on-axis nor a speaker unit response 60Â° off-axis deviate more than Â±3 dB from the speaker response 30Â° off-axis and the speaker responses on-axis do not deviate more than Â±3 dB from a nominal sensitivity level Lnom; wherein said nominal sensitivity level Lnom is defined as the average sensitivity level between 300 Hz and 1000 Hz; wherein said center-to-center spacing D1 between the essentially identical speaker-units in said at least one line-source of acoustical radiation is less than one half of a wavelength corresponding to a frequency FC-C; and wherein said frequency FC-C, is, at a crossover attenuation of at least 24 dB/octave, one quarter of an octave lower than FMAX, and, at a crossover attenuation that is less than 24 dB/octave, FC-C is equal to FMAX.