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Not too much effect, I think. Basically you need to concentrate during a game - that's the most important part.
I have seen people listening to music on headphones before a OTB round.True it gives them confidence but with a song hummning on one side of your brain and in your sub-conscious mind moves will playing on another side, for example,"Being held by you" a phrase in a song in running in your head. and you see an intermediate move and a candidate move,Bxc6+ and Rxa2.You forget both these moves and play a different move.This has happened to me atleast half a dozen times.Very annoying.even though you are in a good mood,Chess before a tournament or even a fun-serious game can drastically kill your play.
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