ABSTRACT
Acommonpropertyofgases,liquids,andsolid-statematerialsiselasticity [1-3,6].Ifsomeforcedeectsacertainportionofsuchamedium,this deectionpropagatesawayataspeedthatdependsontheelasticproperties of the medium. The deection of the molecules results in varying the local mediumdensityandpressurefromitsequilibriumlevel.Thetotalpressure pt at certain location is
p p pt eq= − [Pa] (1.1)
where peq is the equilibrium pressure p is called the sound pressure caused by the propagating disturbance
Thesoundpressureisthemostimportantandusefulquantityinacoustics. Theperceptionofsoundiscausedbythesoundpressureactingontheeardrum. As will be shown in later chapters, the acoustic properties of enclosuresdependonthespatialandtemporaldistributionofsoundpressure. Becausethesoundpressureisascalarquantity,itisusuallymanageableby simpler equations than equations with vectors.
