Burn-in is half physical, half psycho-acoustical. Over time, your ears grow acustomed to a particular sound and establishes it as the current "reference." I've found most physical burn-in for electronics (not speakers) is accomplished in the first few hours of use. -Ed
componet/cable burn-in
I understand the changes involved with component burn-in but wonder why it is not possible to purchase a component and especially a set of cables that are already to perform right out of the box? I'm running in a cd player right now for a week day and night. It's a cheap one so I can understand that the manufacturer can't afford to do this but with the prices for the cables on the market, what's the excuse? This burns me in!