Sound synthesis technique based on physical model is a kind of accurate method to describe object's sounds.The method is based on partial differential object's vibration equation of to synthesize sound directly.Presently

the method is becoming an important research field on digital sound synthesis.Under our research

we discover that the PDE cited by many researchers for a long time is extreme limitation

and prove those by theory and experimentation.And then

we derive a new PDE by dynamics elements.Last

we prove that our new PDE is correct.So

a new basic and universal equation has been proposed by the paper for sound synthesis based on physical model.