If a rat dies near a steam pipe, the body wonât dry and the smell can be horrible for weeks. The odor from a dead mouse may last only a day or two. In fact, there may be no noticeable odor from a single dead mouse but several dead mice in the same area could smell for a few days.
Most popping or crackling sounds in an audio system come from a bad or dirty connections. Sometimes they do come from a faulty unit or component, but in most cases it is a connection issue.
Re: Loud crackling / popping in one speaker. Be surprised if mains power had anything to do with it - as in I'm struggling to think of mains related issue that would cause noise only in on speaker. More info about your setup might help others to suggest causes/solutions.