"The piano is a monster that screams when you touch its teeth"

This quote by Andres Segovia is a metaphor for the power of music. The piano is a beast due to the fact that it can produce such powerful and emotive noises. When you touch its teeth, or keys, it yells with the music it produces. Segovia is suggesting that the piano is a powerful instrument that can evoke strong emotions in the listener. He is also recommending that the player should have a certain level of ability and understanding to be able to make the piano shout with emotion. The quote is a tip of the power of music and the skill needed to make it come alive. It is a suggestion that music can be an effective force which it must be respected and appreciated.