Echo sounds while playing music by imac
Hello,
Need your advice. Recently i realized that my Imac picked up some echo sounds while i playing music or youtube. First, i have doubt abt the quality of video in youtube then i changed to Spotify but its still there. I wanna get rid of it. I have tried to minimum the volume of input in Sounds but it doesnt help. Been searching thru few threads, doesnt help much. Appreciate if you could give me any idea to solve this?
Thanks
iMac 27", OS X 10.11