well occasionally (about 1 out of 5 times) when ever I turn either my 360 or PS3 off (both share the same HDMI cable), there is a really loud popping/scratchy sound that bursts out of my speakers for about a milisecond, but I mean its really loud. and then after that happens, I turn my TV off and the sound happens again. I am about 100% sure it has something to do with my HDMI cable because it never happened with my 360 before I got the cable, and it happens with the PS3 as well. I just want to know if there is something I can do to fix it, or if it will cause some sort of long-term damage to my TV's speakers?

Probably not the cable. Probably the HDMI device(s). The digital handshaking that occurs probably causes the popping sound, (this would occur on any cable, it is at the fault of the devices, either the consoles, TV, or reciever). Bottom line, it's probably not fixable, as my analog setup used to do this (component video/composite sound), which is common, but my old S/PIDF digital setup did it also. It's hit or miss on the devices, usually higher quality devices won't do it, but not always.

What kind of TV do you own Wenis? I'd have to go with what sc7 is saying, but sometimes you hear about the popping noises with particular makes/models.