As per the title, I've had this head unit for around a year and a half now and I've just now started to hear a little hiss coming from the left side speaker. Prior to me changing the speaker to an aftermarket one, the stock speaker was dying and sounded like distorted crap! I've replaced the speaker and its still there. It's not as bad however the hiss is surly there and you can hear it after about 5 minutes, your ears adapt to it and it's annoying! No idea what the issue is especially since I've changed the speaker?