Changing+Sound

**How does sound change?**
Sound can change both in amplitude and in frequency. The musical equivalents of these changes are changes in loudness and pitch.

Amplitude of the sound is changed by simply changing the amplitude of the vibrations that are creating the sound. If vibrations occur with a larger amplitude, they will produce a louder sound. Likewise, if vibrations occur with a very low amplitude, the sound produced will be very soft.

Another way sound can change is in frequency. Sounds with a higher frequency have a shorter wavelength, and a higher pitch. Factors that affect frequency are the length of the object that is vibrating, the thickness of the object that is vibrating, or to change the tension on the object that is vibrating (for example, the strings on a guitar). When changing the length of the object, adding length lowers the frequency, while shortening the length increases the frequency. Multiplying the length by the twelfth root of two gives the length of the next note. When changing the thickness of the object, objects of the same material will vibrate with lower frequencies when thicker, and higher frequencies when less thick. When changing tension on the object, it will vibrate with a higher frequency when more tension is applied, and a lower frequency when less tension is applied.

Watch as we demonstrate how to change sounds by length in the following videos.

media type="file" key="Changing Sound 2.m4v"media type="file" key="Changing Sound 1.m4v"