I am a musician trying to develop some physical modelling synthesizers (synthesizers modelling natural instruments). In particular, drums and guitar. It is my impression from playing drums and guitar that when you strike a drum head or guitar string very aggressively, there is a natural "pitch bend". It sounds as if the note starts slightly sharp from the added tension of the strike. Then rapidly (exponentially) it settles to the resting pitch a little below the pitch during the initial attack. I am wondering if my ears are wrong though and if perhaps what I perceive as a downward pitch bend is really just rapid decay of high frequency modes/resonances. It makes sense to me there should be a slight pitch bend based on how much tension is on the membrane/string at any given time but I don't have much physics knowledge so I'm not sure. Can anyone confirm or refute whether this is actually what's happening? Thanks a bunch.