I don't think it makes any difference what you listen to.You can listen to conversations,movies,songs or lectures,but if you don't try to TALK,I mean communicate with another human, you will not improve.This is because LISTENING and READING are PASSIVE activities,and SPEAKING and WRITING are active.SO if you want to be able to communicate with other speakers you should try to speak as much as you can.OF course you must do all the skills.