Transposing and Changing Keys
Sometimes it is necessary to change a piece of music from one key to another. This process is called transposing. There are is now software that can do this task very quickly. However, there is no reason why doing it by hand (and mind) should be terribly difficult.
Wind instruments such as trumpet, sax, clarinet, etc., are tuned differently and will actually play a different note from a C instrument such as a guitar when reading from the same music. When writing music for an ensemble, it is important to take this into account. If you gave a trumpet player music written for the guitar, the trumpet would sound a whole step lower. To compensate you must rewrite the music a whole step higher than the guitar music. Or, rewrite the guitar music to be a whole step lower.
The chart at the bottom of the page can help you "translate" a piece of music so it can be read by another instrument. Here's how you can do it. LetÕs say you record yourself playing a piece of music in the key of C major on a guitar and you want to write it out so you can accompany yourself on a trumpet. First, you need to know the tuning note of the two instruments. The standard guitar tuning is C while the standard tuning of a trumpet is Bb. If you want to write the music for the trumpet, you will write its music in a key a whole step higher to compensate for the tuning. This means you need to write the same music in the key of D Major. That's one whole step higher than C. If the first note on the guitar is an A. The first note on the music for the trumpet will be B.
Once you have determined if you are raising or lowering the original key you can use the chart to translate the each note of the piece of music. Using the following steps.
1) Start from the gray area. Find the note you want to transpose in this area.
2) Next, identity the interval between the tuning note of each instrument.
3) Find the row that interval appears on.
4) Read across until you find the note that is directly above (or below) the note in the gray area you want to transpose. This is your new note.
5) Be sure to write the note so it fits the key signature of the new key.
Up or Down the Scale
There are to ways to look at transposing, either going up the scale or down the scale. You can get to the same note either way. There are times when you might think of going from C to G as going up the scale a perfect fifth. However, there are times when going from C to G is going down the scale. Looking at it from this direction you are going down a fourth. Either way, you end up at G.
Steps Between Notes
This column shows the number of steps between notes on the gray ÒFromÓ line to the ÒToÓ line. Assuming you are going up the scale. All of the notes on the row labeled with the 4-1/2 are a major sixth above the notes on the gray row. Assuming you are going up the scale. If you are going down the scale, you would look a the row below the gray line marked minor third.
This column shows the interval between the notes on the ÒFromÓ line and the ÒToÓ line. As with the steps between notes you can identify the "To" row by the intervals name, like major sixth or minor third.
The chart below can help you quickly and accurately transpose from one key to another.
Below is a quick reference chart that shows what notes transpose to what notes given a particular tuning. If you are reading piano music and want to write out the music so your trumpeter can play along, use this guide determine what note you should write. For instance, when you see a D on your music you would write an E on your trumpet score. However, you will need to make allowances for key notation.
If your piano music is written in the key of G (with the F#) and you encounter an F#, you have two transposing choices, G# or Ab. Since your trumpet will be playing in the key of A (the key a whole-step above G), you will write G# because it belongs to that key.
The chart below shows the tuning for some common instruments. You will note that some instruments come in different turnings. So, you will have to know if you are writing for an Eb clarinet or a Bb clarinet.