The human ear can distinguish two characteristics of sound. These are the loudness and pitch, and each refers to a sensation in the consciousness of the listener.
- It is easy to distinguish among loud and soft sounds. The term loudness of a sound is self-descriptive. It depends primarily on the amplitude of the sound wave.
- The larger the amplitude, the louder the sound.
Note: The standard unit of sound level is decibel. A sound is judged to be twice as loud as another, if its sound level is about 10 decibels higher. The reason why it is 10 and not twice the value is that decibel is a logarithmic unit.
- The pitch of a sound refers to whether it is high (sharp), like the sound of a violin, or low, like the sound of a bass drum. The physical quantity that determines pitch is the frequency.
- The higher the frequency, the higher the pitch.