Tones are distinguished from noises by their ability to hold a particular frequency of pitch. Noises are a mixture of many frequencies all at once, while a tone focuses on either one frequency or a carefully arranged group of frequencies. The tone that is used most frequently as the standard for establishing pitch is 440mhz, which is the pitch "A" used on an oboe to set pitch for the orchestra.
There are three basic parts to musical tone. "Pitch" is the frequency of vibrations that produces a particular note, such as "A" or "A#" or "Ab." "Intensity" describes how loud or soft the pitch is. "Quality" is most difficult to define and the most subjective of the three. This is sometimes also referred to as timbre and describes the overtones that distinguish a particular instrument or musician. When someone discusses the tone of a player, they usually are referring to this quality.
Certain sounds are referred to having a "bright" or "dark" tone quality, while others are "warm" or "open." Sometimes these differences in tone are obvious, such as the "warmth" of brass compared to the "brightness" of woodwinds. There are distinct differences in tonal quality between two musicians playing the same instrument, or the same musician playing two different instruments.
The most well trained ear can detect differences in tone that can be attributed to differences in instruments. For example, manufacturers have slightly different processes that can produce slight variations in tone quality. Different types of wood or metal used can influence sound quality. One of the biggest influences in tone quality comes from the sound source, be it a mouthpiece, string or bow. The importance of this particular accessory is such that bows or mouthpieces can cost as much or more money than the instruments themselves.
Differences in tone can also be attributed to the ability or personal style of the musician producing the sound. Professional wind musicians are able to alter tone quality by changing the embouchure, or the position of their mouth. Performing vibrato, or the vibration up and down of a particular pitch, is also a way to alter tone. Some musicians prefer non-traditional tone quality. For example, it is traditional for the clarinet to have a warm tone without the use of vibrato. The famous clarinetist Benny Goodman used vibrato and had a relatively bright tone, which has become the traditional use of the instrument for jazz and swing.