According to the developer, this program should be used together with GeatdyAudioDevice program. You can obtain a download link for the mentioned application from Mac Informer's application page. If your problem isn't solved by this, try to check if you made the appropriate settings for the recording process. Also, it is not advised to record a song from your external speakers. This might be the reason for the background noise. In this matter, you should always use an internal source for your recordings.