| 摘要 |
HIGH EFFICIENCY LOW FREQUENCY SPEAKER SYSTEM A loudspeaker (34,134) excites a quarter wave resonant air column that is folded forward on itself. The column is closed at one end and has an output port located at the other. The output port (20,120) is in line with the speaker so that the one speaker can excite air both at the output port and at the closed end of the resonant column. At resonance, the column loads the speaker, and the speaker regeneratively drives the column output. At other frequencies output from the port is partially from vibration of the air column and partially from the speaker. At resonance the direct speaker output regeneratively reinforces and combines with the output of the resonant column, which has a length of one-quarter of the wavelength of sound propagated in air at the resonant frequency.
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