Recent development of digital audio technology has made it possible to realize a transmission system in which signals of frequency between several Hz and 20kHz are recorded in and reproduced from a digital medium such as a CD or DAT. In order to give music the presence of a concert hall or the character of the original acoustic fields, it is essential to design and realize a listening room and a speaker system which reproduce with low distortion not only musical sound signals but also such tactile sound signals of several Hz to 100Hz as those of vibration transmitted through floors and in air.
For audio listening in an automotive cabin in particular, improvement of the system's tactile sound reproduction capability is effective in making the maximum use of the digital media, as well- as in coping with the low frequency sound masking while the automobile is running.
