The Difference Between Tuning and Key

I have a number of students who have trouble understanding the difference between the key of a song and the tuning of their banjo or they feel they can only play in the key of G if their banjo is tuned to open G tuning.  I’ll try to clear this up here.

Let’s start with definition of the two:

Key - a system of tones and harmonies generated from a hierarchical scale of seven tones based on a tonic (the key of G major)

Tuning - the process of adjusting the pitch of one or many tones from musical instruments to establish typical intervals between these tones.

Different methods of sound production require different methods of adjustment:

• Turning pegs to increase or decrease the tension on strings so as to control the pitch.
• Modifying the length or width of the tube of a wind instrument, brass instrument, pipe, bell, or similar instrument to adjust the pitch.

As most of us know, the most common tuning for the 5-string banjo is open G tuning.  What confuses many students is that they feel they can only play a song that is in the key of G if the banjo is tuned to G tuning.  Thus, if their banjo was tuned in C tuning, they feel they can only play a song in the key of C.  This is not true.  Any stringed instrument can play a song in any key no matter what tuning it is in.  While it may be harder to play in certain keys while in a particular tuning, it is still possible.  This can all be done without the use of a capo (a capo is a clamp fastened across all the strings of a fretted musical instruement to raise their tuning by a chosen amount).

The tuning of an instrument does a couple things:

1. It makes it easier to play songs that are in a specific key

2. It gives your instrument a different tone

3. It allows you to play your stringed instrument with more open strings.  Open strings have a different tone than strings that are fretted. 

What confuses some banjoists even more is that they hear of certain wind instruments such as a tenor saxophone that are Bb instruments. These instruments are called Transposing Instruments.

Wikipedia’s description for Transposing Instruments goes as follows:

A transposing instrument is a musical instrument whose music is notated at a pitch different from the pitch that actually sounds (concert pitch). Playing a written C on a transposing instrument produces a pitch other than C, and that pitch identifies the interval of transposition when describing the instrument. For example, a written C on a B♭ clarinet sounds a concert B♭.

Rather than a property of the instrument, the transposition is a convention of music notation—however, instruments whose music is typically notated in this way are called transposing instruments.

Reasons for transposing[edit]

There are several reasons to transpose music for certain instruments.

Making it easier to move between instruments in certain families of instruments[edit]

Many instruments are members of a family of instruments that differ mainly in size (see examples below). The instruments in these families have differing ranges, with the members sounding lower as they get larger; but an identical pattern of fingerings on two instruments in the same family produces pitches a fixed interval apart. For example, the fingerings which produce the notes of a C major scale on a flute, a non-transposing instrument, produce a G major scale on an alto flute. As a result these instruments' parts are notated so that the written notes are fingered the same way on each instrument, making it easier for a single instrumentalist to play several instruments in the same family.

Instruments that transpose this way are often referred to as being in a certain "key", such as the "A clarinet" or "clarinet in A". The instrument's key tells which pitch will sound when the player plays a note written as C. A player of a B♭ clarinet who reads a written C will sound a B♭ while the player of an A clarinet will read the same note and sound an A.

Examples of families of transposing instruments:

• saxophones
• clarinets
• flutes

Examples of families of non-transposing instruments:

• trombones^[1]
• tubas^[1]

Recorders are either untransposed or in some cases transposed at the octave.

Horn crooks[edit]

Before valves became common in the 19th century, the horn (except for slide-bearing versions such as the sackbut and its classical and modern descendant, the trombone) could play only the notes of the overtone series from a single fundamental pitch. This fundamental could be changed by inserting one of a set of crooks into the instrument, shortening or lengthening the total length of its sounding tube. As a result, all horn music was written as if for a fundamental pitch of C, but the crooks could make a single instrument a transposing instrument into almost any key. Changing the crooks was a time-consuming process, so it took place only between pieces or movements. The introduction of valves made this process unnecessary (though Richard Wagner wrote horn parts as if crooks were still in use, evoking a tradition that was quickly becoming archaic). F transposition became standard in the early 19th century, with the horn sounding a perfect fifth below written pitch in treble clef. In bass clef composers differed in whether they expected the instruments to transpose down a fifth or up a fourth.

Reconciling pitch standards[edit]

In music of Germany during the Baroque period, and notably in the music of Johann Sebastian Bach, instruments used for different purposes were often tuned to different pitch standards, called Chorton ("choir pitch") and Kammerton ("chamber [music] pitch"). When they played together in an ensemble, the parts of some instruments would then have to be transposed to compensate. In many of Bach's cantatas the organ part^{[clarification needed]} is notated a full step lower than the other instruments.^[2] See Pitch inflation.

A few early-music ensembles of the present day must do something similar if they comprise some instruments tuned to A415 and others to A440, approximately asemitone apart. Modern builders of continuo instruments sometimes include moveable keyboards^{[clarification needed]} which can play with either pitch standard.

So to sum up, you can play any song in any key on your banjo in any tuning.  You can also play your banjo in any tuning with any other instrument.  Now go out there and explore playing your banjo with other instruments and play some tunes that are in keys other than G while your banjo is still in G tuning!