A DIRECTION- AND FREQUENCY-INDEPENDENT LOUDSPEAKER- OR MICROPHONE-COLUMN OR A LOUDSPEAKER- OR MICROPHONE-SURFACE

摘要

An arrangement for receiving or reproducing sound waves, comprises five, seven or nine transducers situated in line at equal distances from each other (such as for example 1 to 5), all transducers each being connected to the same transmission channel via an individual amplitude control device (11 to 15). The amplitude control devices are adjusted so that the ratios between the conversion factors of the combinations of a transducer and an associated amplitude control device, viewed from the one end of the arrangement to the other end, are 1 : 2n : 2n2: -2n: 1 in the case of five transducers, 1 : 2n : 2n2 : n3 - n : -2n2 : 2n : -1 in the case of seven transducers, and 1 : 2n : 2n2: n3- n: 1/4(n4 - 1) - 2n2: -(n3-n) : 2n2: -2n: 1 in the case of nine transducers. This results in an output signal of the arrangement which is substantially independent of direction and/or frequency. Moreover, the arrangement may be realized in a very simple manner. The invention also relates to a combination of five, seven or nine arrangements as described in the foregoing (for example 41 to 45), which are situated adjacent each other or in line at equal distances from each other. The arrangements each comprise a further amplitude control device, which devices are all connected to a transmission channel of the combination. The amplitude control devices are adjusted so that the ratios between the conversion factors of the arrangements viewed from the one end of the combination to the other end, are 1 : 2m : 2m2 : -2m : 1 in the case of five arrangements, 1 : 2m : 2m2: m3-m : -2m2 : 2m : -1 in the case of seven arrangements, and 1 : 2m : 2m2 : m3 -m: : 1/4(m4- 1)-2m2 : -(m3- m) : 2m2 : -2m: 1 in the case of nine arrangements.