I have Polk's all around in my HT. Today I hooked my Direct TV TiVo into my HK AVR 225 via an optical cable. When changing channels there is a short delay on sound, the picture comes on screen then maybe a second later the sound follows. When the sound comes in even at low volumes a speaker crackles or pops I guess is the sound it makes. It doesn't seem to be the same speaker all the time it can be a different one each channel change. The speakers never do this during radio or CD playback nor during DVD movies. Any ideas? Is it harmful at all it sure is annoying. Is my optical cable bad? Something to do with my receiver? It doesn't do this with a regular analog audio hookup only with the optical cable.