Pitch is the property of sound which determines whether the sound is high or low. Pitch is determined by the number of vibrations per second made by the sounding body. Comparatively slow vibrations produce a low sound, while rapidly vibrating substances produce a high-pitched sound. This difference may be quickly observed by entering a machine shop where the machines are running at a low speed and comparing the low drill sound to the high-pitched sound produced in a woodmill where the machinery is running at a high speed. Low speed gives a low vibration, while high speed gives a quick vibration It is possible to detect the difference in the sound produced by two bodies of different composition, but with the same intensity and pitch. The property of sound by which we are able to distinguish this difference is called quality. Quality depends upon the form of the vibrations.