Created on 04/02/2008 18:26.
Column designers are making renewed efforts to go beyond traditional designs. Counter-aperture acoustic systems were born.
For almost a century of work on the problem of sound emission, the designers of acoustic systems have made great progress in solving it, but it is still too early to speak about the perfection of sound reproduction. In most cases, the columns use electrodynamic transducers. And while the search for new ways of converting electrical signals into acoustic waves continues – it is enough to recall the electrostatic speakers, the leader in the production of which is Martin Logan, or NXT “singing panels” – but these advances do not put an end to the dynamic heads as the basis for new technologies. radiation of sound.
The American company Tymphany, for example, has developed the Linear Array Transduser (LAT), a compact system consisting of small speakers but capable of emitting low frequency sound. The omnipolar Mirage speakers have gained wide popularity, forming a circular radiation pattern due to the special design and location of the tweeter. In some models of different brands of subwoofers, the speaker is located on the bottom edge of the cabinet. With this design, the sound is emitted by an air mass enclosed between the floor and the woofer cone. We can say that the idea of counter-aperture acoustics is in the air. What does it consist of?
If two identical speakers are placed “facing” each other at a certain distance and the same electrical signal is applied to them, then a kind of pulsating air sphere will form between them, which will become the source of areas of compression and rarefaction of air propagating in space, that is sound waves. This principle is called counter-aperture. Why is such a scheme better than the usual one? First of all, by the fact that the radiation becomes more efficient, that is, to create the same sound pressure, less displacement of the diffuser is required, which means that there will be less nonlinear distortions. And at the same time, the center of radiation is at one point, that is, there will be no phase mismatch problem, as when placing several speakers on the front panel of the column. In this system, the movement of the diffusers occurs in the direction perpendicular to the propagation of sound, and, therefore, its distortions associated with the Doppler effect will be excluded.
A counterperture speaker system creates a circular field pattern. Because of this, in the sound reaching the listener, the proportion of waves reflected from the walls increases, which means that the influence of the acoustic properties of the room on perception increases. Therefore, the sound panorama formed during the playback of recordings differs from the one to which we are accustomed. Someone will like these new sensations, but others will not.