Page  108 ï~~TIME DOMAIN COMPUTATION 0) ACOUSTIC FIELD BY RETARDED HOLOPHONIC SY] ADRIEN Jean-Marie, EOTVOS Peter. IRCAM Place St Merri Paris 75004, uucp net adress. j Tel (1) 42 77 12 33 ext 4814 Telex 212 034 F IRCAM Abstract We present in this paper a first ap variations of the acoustic field variables at an recorded or synthesized surface velocities on a vib computation algorithm, based on the retarded pot modal sound synthesis technique, and aims at t diffusion of synthesized or recorded sounds in spac Introduction Sound synthesis software based on elastic and elastc synthesis methods have been successfully developed i.4- - -" -- -11-- -- - - "-1 -

Page  109 ï~~directivity measurements are available. Resulting appi phenomena but are nevertheless poorly adapted to oi significant data along the radiating structures, and radiation problem in the time domain, obtaining tht field. Related computation techniques have been devi scattering problems in electromagnetism and more outside a vibrating surface may be expressed in the fol P(ro,to) 1 2Kt dS.R pi,to 1 Rc R2 where p is the pressure at the observation point at ti and the observation points, dS the surface element vibrating surface at the integration point and c the veli assumption underlying the use of this equation is that vibration phenomena, more precisely that the vibratic S1a " -, Â~. 1 "- 1Â~1.0 - 1

Page  110 ï~~References Cl, ADRIEN Jean Marie (1989) The Representations of Sound", G.De Poll, A.Pic, Â~2) CADOZ Claude (1979) Synth se So Application aux Sons Musicaux, Phd Disserta [3] MAHE Herve (1989) Contribution I Acoustique de cibles Imp6n6trables de Formes II U U

Page  111 ï~~-r- - - S r i