Before Tish'a b'Av we are in a type of mourning so the laws are similar to mourning for a parent. There are three stages:
The “Three Weeks”: The least severe stage starts three weeks preceding the Ninth of Av
The “Nine Days”:  The next-most severe stage begins on Rosh Chodesh Av.
“Week” of Tish'a b'Av:  The most severe mourning is during the “week” of Tish'a b'Av (beginning after Shabbat preceding Tish'a b'Av).