1. Field of the Invention
The present invention relates generally to the design of acoustic horns for use in a speaker system.
2. Description of the Prior Art
In the design of acoustic speaker systems, typically a combination of speakers is provided to optimize the performance of the speaker system in the low frequency ranges, mid-frequency ranges, and high frequency ranges. Thus, a conventional “three-way” speaker system will have individual speaker components addressing these three frequency ranges.
Several prior art attempts have been made to create a single speaker that produces sounds in multiple frequency ranges. For example, U.S. Pat. No. 5,526,456 issued to Heinz discloses a multiple driver single horn speaker. In Heinz, the high frequency and low frequency sound take parallel paths into the horn. However, the configuration of the Heinz loud speaker produces interference between the various frequencies as well as irregularities in the sound produced from the horn.
U.S. patent application publication Ser. No. 2002/0014369 by Engebretson discloses a multiple driver sound system. The Engebretson publication also fails to cure the interference and the irregularities between the frequencies because of the failure of the frequencies to promulgate through the same horn section.
Other attempts to solve these problems have resulted in sound drivers being placed coaxially. This topology has been used in an attempt to achieve a more uniform pattern control in a more compact system. For example, U.S. Pat. Nos. 4,283,606 and 4,619,342 both issued to Buck disclose a low frequency transducer and a high frequency transducer having coaxial acoustic centers. These prior art arrangements still suffer from three basic problems. First of all, the high frequency horn shadows the mid frequency sound, causing the response irregularities. Second, the unequal time delay between the two frequencies causes frequency response problems unless there is a specific delay correction applied. Finally, the directional coverage pattern produced from these prior art devices has significant peaks and dips at and near the crossover frequency at locations off the acoustical axis.
Thus, there is a continuing need in the art for an improved speaker system which would permit higher and lower frequencies sources to utilize a common horn.