cackling noise from speakers?

so i was hearing these noises every now and then that sounds like ten pebbles hitting my windshield. i paid it no mind until i was noticing that they were coming on every so often. upon further investigation they sound like they are coming from the speakers. i (listen) to youtube stuff on my drive and so when i pause the video the noises stop. sometimes they come on when im listening to pandora or my usb drive music.

any thoughts?

theyre hella annoying sometimes and concerning if my speakers are blown or something wrong with firmware and such. they go away but every now and then they pop up.