Electroacoustic apparatus for reproducing lowest to medium frequencies

DETAILED DESCRIPTION A primary object of the present invention is to provide an improved electroacoustic apparatus which transmits sounds up to less than 30 Hertz with high efficiency and a frequency characteristic as linear as possible and which also guarantees a reproduction up to about 2500 Hertz.
It is a further object of the present invention to provide an electroacoustic apparatus in which undesired reflections of the sound energy back into the space between the loudspeaker and a wall extending behind the loudspeaker are avoided by a horn element wall which more than that advantageously prolongates the horn toward its throat whereby the point of attachment of said horn element wall is overbridged by another horn element wall which advantageously stabilizes the wall construction as well as effects a good sound direction to the throat.
It is another object of the present invention to provide an electroacoustic apparatus with minor technical expenditure which has, due to its good approximation in the horn area to an ideal exponential horn shape, such a high acoustic radiation impedance that even low bass frequencies can be reproduced with good linearity in the frequency characteristic of the reproduction.
It is a further object of the present invention to achieve good sound amplifying effect by avoiding on the one hand sharp break or knee points impairing the radiation characteristics as far as possible using an exponential approximation by means of a multi-stage polygonal course comprising five plane horn element walls, and, on the other hand, by making it possible to increase the relative sizes between throat and mouth opening of the horn so that the sound is radiated in a better directed manner.
It is still another object of the present invention to provide an electroacoustic apparatus in which two foldings of the horn with a 1.
5 fold unbifurcated or unforked folding are substantially reflectionless by means of the exponential-functionally bent horn element walls.
It is still a further object of the present invention to provide an electroacoustic apparatus which can be materialized with minor technical expenditure so that the whole spectre in the range between lowest and medium frequencies can be covered at reasonable cost by the apparatus according to the invention