Guitar/Tuning the Guitar
From Wikibooks, the open-content textbooks collection
Sound is caused by the disturbance of particles in the air, usually by vibrations. The disturbance propagates through the air as a wave. When a string is attached to two points, like the strings on a guitar, striking it causes it to vibrate at a certain frequency which causes a soundwave of similar frequency. The length, thickness and tightness of the string determine the frequency of vibration and therefore the pitch of the note it produces. When a string is plucked the string is stretched to set it in vibration. A shorter or tighter string is harder to stretch and therefore vibrates faster than a longer or looser string. A thicker string produces lower notes than a thinner string because the higher mass of the thicker string is more difficult to set in motion. For this reason the strings of the lower notes usually have extra metal cladding to increase their mass.
There are many different ways to tune a guitar, but the most common is called standard tuning, or E tuning. In standard tuning the strings should be tuned to the notes EADGBe. This means that the thickest string should play the low E note, and then the next thinner should play an A and so on, finishing with the thinnest playing a high E. When the guitar is tuned, strumming all the strings at once produces a chord. Chords are explained in greater depth in the chords chapter.
Standard tuning is often represented visually like in the diagram below. Note that the upper case E represents the thickest string, and the lower case e represents the thinnest string, which means that the lowest string on the diagram is the highest string on the guitar. This is meant to represent how the guitar looks when a player looks down on it.
e|-----------------------|
B|-----------------------|
G|-----------------------|
D|-----------------------|
A|-----------------------|
E|-----------------------|
To adjust the pitch of a string, you twist the tuning peg. To adjust to a higher pitch the string must be tightened, and to lower the pitch the string must be loosened. When doing this, it is important to make sure you are turning the correct peg for the string you are trying to tune. It is both confusing and embarassing when you turn the wrong peg, often because you have to start all over again.
Until you have developed your musical ability, it may be difficult to know exactly what a particular note should sound like. Any guitar or music store will sell tuning aids, such as tuning forks, pitch pipes and electric tuners. When properly used, these allow you to precisely tune each string to the appropriate pitch. Almost every guitar player owns some sort of tuning aid, and new players are encouraged to purchase one.
On the guitar neck, fingering each fret raises the pitch of the note a half-tone. In an octave, there are twelve half-tones, which means that if you play any note, the note 12 frets above that is twice as high in pitch. Any two notes are related by a certain number of half tones, which is called an interval. The interval between the low E string and the A string is called a fourth, which means that the two notes are separated by five half-tones or frets. This relationship of a fourth is the same for any string and the one below it, except for the G and B strings. The note G is separated by only four half-tones or frets, which makes this interval a third. Scales are explained in much greater depth in the scales chapter. Information on general music theory, including scales and intervals can be read in the Music wikibook.
Tuning by ear
Regular Tuning
Tuning by ear (also known as the fifth fret method) involves getting a single string at the correct pitch, and then using that as a reference point to tune the other strings. Because of this, a tuning aid is useful to ensure that the first string is properly tuned. It is best to use the A as the reference string, because it lies in the middle of the root notes of the most commonly played chords. A perfectly tuned A string resonates at a frequency of 440 Hz.
To tune by ear, begin by hitting the A string, and then the low E string. Pick the notes hard, and let the sound ring out, since the louder it is, the easier it is to hear the difference between notes. Turn the tuning peg up or down to bring the notes into unison When the notes are close together, you should be able to hear a very fine oscillation between them. This should get slower when the notes are closer together, and should disappear entirely when they are in tune. Your ability to hear this ossicilation is a skill that develops over time, and you should not become quickly discouraged if it is at first difficult. Once the two notes have been brought into unison continue onto the next string.
On the diagram below, each string has a number indicates the fret you play to tune the string above it.
e|-------------------0---|
B|---------------0---5---|
G|-----------0---4-------|
D|-------0---5-----------|
A|---0---5---------------|
E|---5-------------------|
Also, when tuning it is always a good idea to tune the string upwards to it's proper pitch. By just tuning down to a pitch, you introduce slack into the string and it goes out of tune much faster. So if the string is too high, it is best to tune it very low, and then back up to the correct pitch.
A good way to tell whether the string is perfectly in tune is to see if the other string resonates to it. For example, if you wanted to make sure the A string is in tune with the E, pluck the fifth fret of the E string (hard) and mute it. If the strings are tuned perfectly, the A string should be ringing even after the E string is muted, with little appreciable change in volume.
Harmonic tuning
Another, more advanced method of tuning is called harmonic tuning. In this method of tuning, you use the harmonic tones of the strings to produce high pitch sounds, and then use these to tune. Because the notes are of a higher pitch, they are easier to tune because even minor changes in pitch are more easily noticable. Rather than actually touching the string to a fret, simply touch the string directly above the fret. Then, pluck the string and quickly remove your finger. This should produce a high pitched ringing tone, known as a harmonic.
The easiest places on the string to produce a harmonic are on the 3rd, 5th, 7th, 9th and 12th fret. More information on why is available in the harmonics chapter of this book. Because of the interval between the G and B strings is a third, to tune the string harmonically you must use the low E string.
The diagram below shows the frets one must his to create the necessary harmonics for standard tuning.
e|----------------------7*---|
B|------------------0---5*---|
G|-------------7*------------| * = Play a harmonic at this fret
D|--------7*---5*------------|
A|---7*---5*-----------------|
E|---5*-------------7*-------|
It is also be noted that this method will not provide perfect equal temperament tuning. It is extremely similar, but a picky guitar player may prefer the previous technique.
If there is a substantial difference in pitch when tuning via regular or harmonic, the intonation on your guitar is off. The easiest way to tell, is to perfectly tune your 12th fret harmonic with a tuner, and then fret at the twelfth. If the 12th fret is not in tune, while the harmonic is, your intonation needs adjustment.
Using a Tuning Fork, Pitchpipe, or Keyboard
Tuning Forks
A tuning fork is a piece of U-shapes piece of metal that, when struck, emits a particular tone. Tuning forks are good becuase, unless bent, they will always emit the same note. The most common tuning forks resonate at either an A, which at the frequency of 440 hertz, or C. Using a tuning fork is generally reccomended for more advanced players.
To use a tuning fork, gently striking the it against the heel of your hand and it will vibrate. Then, set the base of the fork against the body of the guitar. The sound of the fork will then be amplified through the guitar, and you can use it to tune your strings. It is important not to strike the fork against a hard surface, as this may bend the fork out of tune.
If you are using an A tuning fork, then you should tune first to the harmonic on A string. However, you can also use the 5th fret on the low E string, the 7th fret of the D string, the 2nd fret on the G string, or the 5th fret on the high E string. All of these frets produce an A, although some are in a higher octive.
Pitchpipes
A pitchpipe is much like a tuning fork, in that it only plays one note and that note is used for tuning. To use a pitchpipe, you blow through the end like a whistle. You can also purchase electronic pitchpipes, which emit notes through a speaker. Some electronic tuners also have this feature.
Keyboard
Using a keyboard can help as it has all the necessary keys and never goes out of tune. Strike the string and hit the key at the same time to recieve the appropriate tension. It is preferable to own a pedal for the keyboard for this approach.
Using an Electronic Tuner
Electronic tuners are a quick, accurate, and precise method of tuning. A tuner can be used in two ways, either through a built in microphone which detects sound, or by directly jacking in an electric guitar. When a note is played, the tuner determines the note you are playing, and then represents visually how sharp or flat the note is. Most models use a combination of lights and a display screen to indicate the tone of the note.
Electronic tuners can be easily drowned out by background noise when you do not jack directly into them. Because of this, they are best used in a quiet environment.
Factors to Consider While Tuning
Modern instruments use equal temperament tuning, and the guitar is no exception. Older methods of tuning have the problem of certain intervals sounding out of tune, while others did not. Advances in guitar manufacture has solved some of these issues, but they are still extremely sensitive to their environment. When the guitar experiences a change in humidity, the amount of moisture in the wood changes, causing it to either expand or contract. Likewise, both the wood of the guitar and the metal strings expand and contract due to changes in temperature. Extreme changes in humidity or temperature can damage your guitar, so you should treat it with proper care. Some structural aspects of the guitar, like the next, fretboard or truss rod, can be adjusted. See the Adjusting the Guitar appendix.
Guitars can be temperamental. If you tune in a room with a set temperature and humidity, then take the guitar into another room that is hotter/colder and/or more/less humid, some guitars can go out of tune. This is because when wood is introduced into an environment where the humidity is different the wood will either absorb moisture or release moisture. When wood does this it swells or contracts in reaction to a high humidity environment or a low humidity environment respectively. This is most apparent in the neck and fretboard of a guitar and truss rod adjustments may need to be made accordingly. See adjustments in the appendices for more information. Additionally the metal strings act in a similar fashion but instead due to temperature, the cooler it is the more they contract and the hotter it is the more they expand. It is best to let the guitar acclimate itself in the room in which it will be played then make adjustments and re-tune it.
When fresh strings have been put on a guitar, they will often fall out of tune very easily. This is because after having been put on the guitar, the strings still have a lot of slack. It will take time to work all the slack out of the string, but the process can be sped up somewhat. After the strings have been put on, loosen them a fair bit and then bend the string gently. Turn the tuning peg up, and then bend the string again. After this, strum chords enthusiastically for a few minutes and tune again. Most of the slack should be gone from the strings, and the guitar should stay in tune.
