can hear the voice声 means “voice” or “sound,” while 聞こえる means “can be heard” or “is audible.” The は marks 声 as the topic. Depending on context, the phrase can also mean “the voice is audible.”
JA: 隣の部屋から子どもの声は聞こえる。
EN: I can hear a child’s voice from the next room.