There are sooo many possibilities that it can be pretty hard to find the culprit sometimes. I read a thread that discussed some of these problems just the other day, but I don't remember where it was. Here are a few things to look into: Are you playing at a different time of day than usual? Has the weather changed much? Are you playing in a different room? Are you playing at a different volume? Have you rearranged the furniture or added some pieces? Changed Strings? Not played in a while? Played other gear and then back to your gear? Any one of these could have an effect on what you're hearing. Let me know if any of this has occured, and then we can try to resolve this problem.