HIGH-QUALITY TWO-WAY HORN ACOUSTIC SYSTEMS
The method of calculating horn acoustic design is presented. It is shown that an exponential horn is the most effective from the point of view of the level of characteristic sensitivity and efficiency. To match the input resistance of the low-frequency (LF) horn with the mechanical resistance of the loudspeaker head (LH), a kind of lowering acoustic transformer is used, which represents some amount of air between the neck of the horn and the diffuser of LH (pre-horn chamber). The transformation ratio of such a chamber n is equal to the ratio of the effective area of the diffuser of LH and the area of horn’s neck, while the input resistance of the horn, reduced to the diffuser and, accordingly, the radiated acoustic power increases by a factor of n2. Based on the proposed methodology, high-quality horn speaker systems (SS) are developed, their parameters and characteristics are presented. The design represents two separate blocks of LF and medium-high-frequency (MF-HF). The low-frequency block is a narrow-necked exponential folded horn with a pre-horn chamber, which assumes that the mouth is set back at a certain distance from the wall or the corner of the room. In this case, the walls, the angle and the body of the speaker are a continuation of the horn. The MF-HF section represents a wide-angle exponential symmetric horn of a cylindrical wave. The front and back sides of the LH are loaded on the horn and emit "forward-backward", forming an eight shape, which is very favorable for multi-channel playback. The midrange-high-frequency unit is freely installed on the low-frequency block, its position is chosen experimentally regardless of the setting of the low-frequency block. The analysis of the measurement results shows the high stability of the impedance module and the acceptable unevenness of the amplitude-frequency characteristic over the entire range of reproduced frequencies. The developed SS has a high level of sound pressure and good sound quality