...let us describe the main relations again. The surface of the wave front radiate from point source increase by pi*d quadrat. For double distance 4times larger surface results. 10 log (1/4) = - 6,02 dB.
Cylinder wave surface doubled by double distance. 10 log( 1/2)= -3 dB. Plane wave surface remain constant by distance, 10o log (1/1)= 0 dB, the level decreases only by diffraction effects and air damping. Focused sources in front of a loudspeaker wall decreases its surface by distance. In focus point the level is much louder as at the radiating plane, dependently its size relationship. At the mentioned Highways the sound sources are not correlated. Additoin of two same level sources would result in +3dB. Nevertheless, that level would decrease by 6 dB. However, the radiation is not a spherical radiation. The Bottom reflects as well as cold air layers at the top. I think the 3dB calculation based at statistic middle value. Greetings Helmut -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120924/2be4783e/attachment.html> _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
