Efficient resonant loudspeakers with large form-factor design freedom

Small cabinet loudspeakers with a flat response are quite inefficient. Assuming that the frequency response can be manipulated electronically, systems that have a non-flat SPL-response can provide greater usable efficiency. Such a non-flat design can deal with very compact housing, but, for small drivers, it would require a relatively large cone excursion to obtain a high SPL. However, mounting the driver in a pipe, the air column can be made to resonate which enables the use of small drivers with a small cone excursion to obtain a high SPL. For these special loudspeakers, a practically relevant optimality criterion, involving the driverand pipe parameters, will be defined. This can be especially valuable in designing very compact loudspeaker systems. An experimental example of such a design is described and a working prototype is presented