聲(sheng)(sheng)(sheng)屏(ping)(ping)障(zhang)(zhang)(zhang)的(de)(de)(de)基本定(ding)義:聲(sheng)(sheng)(sheng)波在(zai)傳播過程中遇到聲(sheng)(sheng)(sheng)屏(ping)(ping)障(zhang)(zhang)(zhang)時，就(jiu)會發生反射(she)、透(tou)(tou)射(she)和(he)繞射(she)三種(zhong)現象。通常屏(ping)(ping)障(zhang)(zhang)(zhang)能(neng)夠阻止直達聲(sheng)(sheng)(sheng)的(de)(de)(de)傳播，并使(shi)透(tou)(tou)射(she)聲(sheng)(sheng)(sheng)有(you)足夠的(de)(de)(de)衰減(jian)，而透(tou)(tou)射(she)聲(sheng)(sheng)(sheng)的(de)(de)(de)影(ying)響可(ke)以忽略(lve)不(bu)計。因此(ci)，聲(sheng)(sheng)(sheng)屏(ping)(ping)障(zhang)(zhang)(zhang)的(de)(de)(de)隔(ge)聲(sheng)(sheng)(sheng)效(xiao)果(guo)(guo)一般可(ke)采用減(jian)噪(zao)(zao)量表示，它反映了(le)聲(sheng)(sheng)(sheng)屏(ping)(ping)障(zhang)(zhang)(zhang)上述兩種(zhong)屏(ping)(ping)蔽(bi)透(tou)(tou)聲(sheng)(sheng)(sheng)的(de)(de)(de)本領(ling)。在(zai)聲(sheng)(sheng)(sheng)源和(he)接收點之間插入一個(ge)聲(sheng)(sheng)(sheng)屏(ping)(ping)障(zhang)(zhang)(zhang)，設屏(ping)(ping)障(zhang)(zhang)(zhang)無限長，聲(sheng)(sheng)(sheng)波只能(neng)從屏(ping)(ping)障(zhang)(zhang)(zhang)上方(fang)繞射(she)過去，而在(zai)其后(hou)形(xing)成一個(ge)聲(sheng)(sheng)(sheng)影(ying)區，就(jiu)象光線(xian)被物(wu)體遮(zhe)擋形(xing)成一個(ge)陰影(ying)那樣。在(zai)這個(ge)聲(sheng)(sheng)(sheng)影(ying)區內，人們可(ke)以感(gan)到噪(zao)(zao)聲(sheng)(sheng)(sheng)明顯地減(jian)弱了(le)，這就(jiu)是(shi)聲(sheng)(sheng)(sheng)屏(ping)(ping)障(zhang)(zhang)(zhang)的(de)(de)(de)減(jian)噪(zao)(zao)效(xiao)果(guo)(guo)。