| 摘要 |
An electroacoustic absorber-diffuser for use in a space such as a recording studio comprises: an electrodynamic loudspeaker comprising a diaphragm and a voice coil. The loudspeaker is mounted on an enclosure such as a baffle. Means, such as a microphone, monitors the total sound pressure acting on the active face of the loudspeaker diaphragm and produces a monitoring signal. An electrical circuit is connected to the voice coil, and comprises: a first filter which generates a first output signal by filtering the monitoring signal by a first transfer function: where Bl is a force factor of an electro-mechanical coupling of the loudspeaker, Sd is an area of the diaphragm, Zm is a mechanical impedance of the loudspeaker, and Zat is a frequency dependent specific target acoustic impedance. A second filter generates a second output signal by filtering a sound source signal by a second transfer function, which is: where Zar is a radiation impedance dependent on a geometry of the enclosure and the space in which the diaphragm radiates. An input voltage to the voice coil is a sum of the first and second output signals. The device may also operate as an absorber only or a diffuser only. |
