For musical 'systems' of tuning see musical tuning. For the automotive form of tuning, see engine tuning. For radio tuning, see tuner.

In music, tuning is the process of producing or preparing to produce a certain pitch in relation to another, usually at the unison but often at some other interval. When one is out of tune, too high or too low, one is sharp or flat, respectively. Usually tuning is done only for the fundamental of a pitch. Tuning at the unison obviously requires the ability to match pitch and tuning at other intervals requires relative pitch.

Different methods of sound production require different methods of adjustment :

• Tuning to a pitch with one's voice is called matching pitch and is the most basic skill learned in ear training.
• Turning the pegs on a guitar (on the machine head) or violin to increase or decrease the tension on the strings so as to make them higher or lower in pitch.
• Cutting or otherwise modifying the length or width of the tube of a wind instrument or brass instrument, pipe, or bell or section thereof so as to adjust the fundamental or the harmonics. The tuning of bells is extremely complicated.

Tuning may be done by aurally testing to the two pitches in question and adjusting the incorrect one until it sounds the same as (or in the correct relation to) the desired pitch. Sometimes a tuning fork or electronic tuning device may used as a reference pitch, though often a piano is used. An orchestra tunes to an A provided by the principal oboist.

Interference beats (or dissonance) may be used to objectively check tuning at the unison or other simple intervals. Since the speed or frequency of the "beats" is the difference between the two pitches when they are brought close enough for beating to occur speed will increase as distance increases, and speed will decrease as distance does, until beating is nonexistent at the exact unison.

Harmonics may be used to check at a unison the tuning of strings which are not tuned to the unison. For example, lightly fingering the node found half way down the highest string of a cello produces the same pitch as lightly fingering the node 1/3 of the way down the second highest string.

There are various systems for establishing which relations between pitches are in tune; see musical tuning for an index of intonation systems. The strings of a guitar are normally tuned to fourths, as are the strings of the bass guitar and double bass. Violin, viola, and cello strings are tuned to fifths. However, the tunings of these instruments may be adjusted, as in scordatura.

External links

• Bells worth listening to: A composer and a sculptor from Melbourne have developed the world's first harmonic bells
• Tonalsoft Encyclopaedia of Tuning
• In-car video players and LCDs for car cinema.
• Alpine Vivid: Car LCD monitors and DVD players.
• Lenco.

Car tuning is the use of technology applied to car passengers, specially GPS, car domotics, ergonomics and in-car entertainment (car-cinema sound and video and DAB radio).

Car cinema includes the use of an LCD (generally attached to the roof), and a DAB radio-DVD player (able to play MP3s and DivX video).