Pitch Please

What’s the difference between a piano and a fish? You can tune a piano, but you can’t tuna fish! In music, tuning is the process of adjusting the pitch tones from musical instruments in 22601order to establish typical intervals between the tones. Tuning is usually based on a fixed reference pitch, such as A = 440 Hz. Being out of tune means that the tone is either high(sharp) or low(flat) in relation to the given reference pitch. An instrument can be in tune within its own range, however, it may not be in tune if it doesn’t match A = 440 Hz, or whichever reference pitch was given. Over time instruments can become out of tune due to damage or typical wear and tear so they must be repaired or readjusted.

Tuning Fork

Tuning Fork

Tuning may be done by playing two pitches and adjusting one of them to match the other. A tuning fork or electronic tuning device may be used as a reference pitch, or a player(if it is an group) may give a pitch for everyone else to match. When playing in an ensemble, the piano is often used as a reference since it can’t be adjusted for each rehearsal. In symphony orchestras and concert bands A or B♭ is typically used as the reference pitch and is given by the principal oboist or clarinetist. A clarinet or an oboe is chosen to give the reference because they have the least fluctuation in pitch as time goes on due to the tight embouchure required for the instrument.

To tune to a specific pitch, the instrumentalist tries to match the given pitch as best as possible by either adjusting how they are producing the pitch( breath support, or posture can have a huge effect) or by adjusting the instrument, if they are using one. The different methods for controlling pitch vary depending on the instrument and the situation. Matching pitch is used with voices and is a basic skill used in ear training. For stringed instruments, such as the harp, violin, or piano, use turning pegs to increase or decrease the tension on strings so as to control the pitch. In the case of wind instruments, modifying the length of width of the tube adjusts the pitch.

Interference beats is a method that a lot of musicians use in order to match pitch, however it is typically more subjective than other methods, like electronic tuners which tell how many cents and in which direction the pitch is off. When tuning instruments using sustained tones and when the two tones are close in pitch but not identical, the difference in frequency generates beating. As the two tones approach the same pitch or frequency, the beating slows down and stops. Since the two pitches produce different periods, when they are both added together(bottom diagram) they produce a beat.  The beat is produced when the crest of one occurs at the same time as the trough of the other since then they effectively “cancel” each other out.

Graph of how beats are produced

Graph of how beats are produced

Image 1: http://ecx.images-amazon.com/images/I/51oRScpu%2BPL._SY300_.jpg

Image 2: http://images.static.steveweissmusic.com/products/images/uploads/popup/WIT-922A.jpg

Image 3: http://www.met.reading.ac.uk/plato2/h-flap/phys5_7f_22.png

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