DEFINITIONS 

WAVELENGTH

    The wavelength is the horizontal distance between any two successive equivalent points on the wave. That means that the wavelength is the horizontal length of one cycle of the wave.
 
 

Wavelength: Horizontal length of one cycle of a wave.







PERIOD

    The period of a wave is the time required for one complete cycle of the wave to pass by a point. So, the period is the amount of time it takes for a wave to travel a distance of one wavelength.
 
 

Period: The time required for one wavelength to pass a certain point. Generally, a longer period indicates a lower pitch.







AMPLITUDE

    The amplitude of a sound is represented by the height of the wave. When there is a loud sound, the wave is high and the amplitude is large. Conversely, a smaller amplitude represents a softer sound. A decibel is a scientific unit that measures the intensity of sounds. The softest sound that a human can hear is the zero point. When the sound is twice as loud, the decibel level goes up by six. Humans speak normally at 60 decibels.

    When the amplitude is doubled, there is four times more energy.  Thus, the energy is directly proportional to the amplitude squared.
 
 

Amplitude: The maximum value of the wave function. The higher the amplitude, the louder the sound.







FREQUENCY

    The number of sound waves passing a point per second is the frequency. Every cycle of sound has one condensation, a region of increased pressure, and one rarefaction, a region where air pressure is slightly less than normal. The frequency of a sound wave is measured in hertz. Hertz (Hz) indicate the number of cycles per second that pass a given location.

PITCH

    How the brain interprets the frequency of an emitted sound is called the pitch. The faster the vibrations the emitted sound makes (or the higher the frequency), the higher the pitch. Therefore, when the frequency is low, the sound is lower.

TIMBRE

    Mixture, or the change in mixture, of all the frequencies.

SYMPATHETIC RESONANCE

    Sympathetic resonance is when the frequencies match and are the same.

BEAT FREQUENCY

    The beat frequency is the difference between two different frequencies played together.

SOUND QUALITIES

    The processes of sound are subjective.  That is, the sounds that are heard vary from person to person.  Frequency is the only process of sound that is objective because the frequencies received are the same but the people perceive them differently.