Journal Article
Shift of the Acoustic Center of a Closed-Box Loudspeaker in a Linear Array: Investigation Using the Beamforming Technique
Journal of the Audio Engineering Society · Volume 63 · Issue 4 · pp. 257–266 · April 2015
Abstract
The center of a spherical wave radiating from a loudspeaker is defined as its acoustic center. This study investigates how the acoustic center of a closed-box loudspeaker is shifted when the loudspeaker is placed in a linear array composed of two or three identical loudspeakers. In order to estimate the acoustic center based on wave fronts, the proposed method measures the sound pressure around the loudspeaker with an array of microphones, and then uses the beamforming method for the reduction of experimental errors. The acoustic center of the loudspeaker at one side is shifted in the opposite direction of the other two loudspeakers, and that of the center loudspeaker is shifted further away from the diaphragm. This implies that the acoustic center of each loudspeaker in a linear array can be shifted differently depending on the relative position of the loudspeaker in the array. Sound field control using an array can be more accurate by taking into consideration the shift of acoustic centers.
