01) Tom qab lub roj teeb khaws cia thiab siv, nws lub neej yog attenuated;
02) Tsis txaus lossis tsis them nyiaj;
03) ambient kub yog tsawg dhau;
04) Qhov kev tso tawm tau qis qis. Piv txwv li, thaum lub sij hawm tawm tam sim no siab, cov roj teeb zoo tib yam tsis tuaj yeem tawm hluav taws xob vim tias qhov nrawm nrawm ntawm cov khoom siv sab hauv tsis tuaj yeem ua raws li cov tshuaj tiv thaiv ceev, ua rau muaj kev poob qis hauv qhov hluav taws xob.