The three basic properties of any pure sound are its pitch, its intensity, and its quality. The Pitch of Sounds Pitch is simply the rate at which vibrations are produced. Another way to define the pitch of a tone is to find its wavelength. The wavelength of a particular tone is equal to the velocity of sound divided by the frequency of the tone. The intensity of a sound has nothing to do with its pitch.
Intensity depends upon the strength of the vibrations producing the sound.
Like light waves, sound waves can be reflected and focused. An echo is simply a reflection of sound. A flat surface, like that of a cliff or wall, reflects sound better than an irregular surface, like a tree, which tends to break up sound waves.