Muaj qhov sib txawv loj ntawm acoustic impedance sib txawv ntawm txhuas thiab cua hauv cov kab noj hniav, thiab kev sib cuag ntawm ob lub xov xwm yuav tsim ib lub suab nrov nrov. When outdoor sound waves are transmitted from the high-density metal outer wall into the low-density air cavity, more than half of the sound wave energy will be directly reflected back to the outside by the interface and cannot continue to propagate indoors. Multi-layer cua kab noj hniav tsim ntau yam impedance reflection interface, suab yoj yuav tsum dhau los ntawm ntau txheej hlau-cua interface txuas ntxiv ua ntej nkag mus rau hauv chav tsev, txhua qhov cuam tshuam yuav cuam tshuam lub suab lub zog. Tom qab ntau qhov kev xav tau superimposed, tsuas yog ib qho me me ntawm lub suab tsis muaj zog tuaj yeem nkag mus rau tag nrho cov kab noj hniav kom ua tiav lub suab rwb thaiv tsev zoo.
ntau txheejCavityDissipatesAcousticEnergy
Tom qab lub suab nthwv dej nkag mus rau hauv lub kaw lus kaw, lawv yuav ua rau muaj kev vibration tas li ntawm huab cua sab hauv. Cua molecules yuav rub thiab sib tsoo nrog ib leeg. Lub zog kinetic nqa los ntawm lub suab tsis zoo yuav maj mam hloov mus rau hauv lub zog cua sov thiab dissipated hauv kab noj hniav. Cov khaubncaws sab nraud povtseg ntau dua hauv cov kab noj hniav, qhov ntev ntawm txoj kev sib txhuam ntawm huab cua, thiab qhov siab dua tag nrho cov acoustic zog noj. Cov kab noj hniav sib txawv me me tuaj yeem hloov mus rau qhov sib txawv wavelength suab nthwv dej, kab noj hniav loj siv cov suab nrov tsawg zaus ntev nthwv dej, kab noj hniav me me txo cov suab nrov luv luv. Cov kab noj hniav sib xyaw ua ke tuaj yeem nthuav dav lub suab nrov txo qhov ntau zaus thiab daws qhov kev mob ntawm kev lag luam uas ib leeg kab noj hniav tsis tuaj yeem sib npaug ntawm lub suab nrov thiab tsawg zaus.
NpogCavityStsim txomResonance
Ib kab noj dav dav yog ib qho yooj yim rau resonate nrog tsheb khiav thiab subway low-frequency suab nthwv dej. Resonance phenomenon yuav ua kom lub suab nrov tsawg thiab ua rau lub suab nrov sab hauv tsev kom pom tseeb dua. Cov txheej txheem ntau kab noj hniav faib cov kab noj hniav loj rau hauv ob peb qhov kev ywj pheej kaw cov kab noj hniav me me, uas tuaj yeem zam qhov tshwm sim resonance tshwm sim tom qab cov kab noj hniav tau tawg. Cov kab noj hniav txheej nrog cov tav sab hauv tuaj yeem cuam tshuam tag nrho cov resonance kev co ntawm qhov profile thiab txo cov suab nrov thib ob uas tsim los ntawm kev co ntawm qhov profile nws tus kheej. Kev npaj tsim nyog ntawm qhov ntim ntawm txhua qhov kab noj hniav tuaj yeem zam qhov tsis tshua muaj suab nrov nrov resonance ncua sij hawm nyob rau hauv lub nroog thiab ntxiv optimize qhov chaw nyob ntsiag to.