transposition while playing

Question

I have sheet music for a song in F major. The original recording of the song is in E so I want to play in that key. All I know is that E is a half step below F. I could just look at all the notes on the sheet music and think that they should be played a semitone lower. What would a professional do?

I was also trying to play the G major minuet (BWV anh. 114) in D major. I did manage to play some measures of the right hand. The first note in the original key is a fifth above the G. And thus I started on A which is a fifth above D. How would a professional have done?

Do you professionals transpose before playing or while playing?

Answer 1

Many professionals need to be adept at sight transposing. Accompanists need to be able to change the key to fit singers, and anyone playing a transposing instrument needs to be able to read concert pitch music at the very least. And anyone who plays in any kind of ensemble with transposing instruments will find it handy to be able to read other people's music at times.

There are a few different strategies. For a transposition of a half or whole step, it might be easiest to simply "move the note" mechanically as you describe in your first paragraph. I also personally find it easy to move by a perfect fourth or fifth, partly because the key signature change is easy, but mentally moving by a third or tritone is gross.

The more general strategy is to do a harmonic analysis on the fly, and re-realize the music in the new key. This isn't as hard as it sounds--you learn to recognize chunks of music instead of individual notes, so you can apply one mental process to an entire phrase. For example, if I see a scale run, I don't have to analyze every individual note, I can simply play the same scale in the target key.

Finally, in some situations you can use a "clef trick", where pretending that the music is in another clef achieves the desired transposition. This only really works if something is convenient; it's not any help if the transposition means you have to pretend it's French violin clef or something esoteric like that. It's rarely usable by keyboard instruments, since you have to find a favorable clef for both hands. And if there are accidentals it can get weird fast.

Answer 2

I play trumpet, and have transposed quite a lot, playing Bb parts on a C trumpet, and the contrary. Also older symphonic parts would notate everything in C and just write "in Eb" when the tonality changed to Eb.

I have only used the clef trick described by @MattPutnam, and wanted to add to it for accidentals. He is right that this strategy applies mostly for monophonic instruments, but I guess it's not impossible to use on keyboards.

Know which accidentals are associated with this specific transposition. Keep any other accidental as they are in the original music. For these "transposition accidentals", you need to either raise or lower half a step compared to the original accidental (even natural).

Example:

You want to transpose a tune a fourth up. If the original was in C, you want to play it in F. Find the clef that makes a notated C turn into an F (it's the second C-clef, mezzo-soprano). This means you need to be comfortable reading in other clefs.

The key signature difference between C and F is one added flat. This means that every time you'd play a B according to your new clef, play a Bb. Every time you'd play a Bb, play a Bbb. Everytime you'd play a B#, play a B. You lower the accidental (even natural) of any B.

Another way to look at it is that you change the key signature according to the transposition. Transposing a fourth upwards means adding a flat to the key signature. Assume original tonality of G major, one sharp. Adding a flat to a key signature is the same as removing a sharp, so your "one sharp" key signature of G major becomes "all natural" key signature. Again, the accidentals are unchanged except for all notated F.

• F# -> B natural
• F natural -> Bb
• Fb -> Bbb

(you lower the accidentals whenever you play any kind of B)

Answer 3

There are several reasons for people to be good in on-the-fly transpositions (not exhaustive):

• They play an instrument, which transposes, but frequently like to play pieces without having access to properly transposed scores

• They play an instrument, where transposition is a frequent requirement (e. g. French horn)

• They are used to it (piano acommpanists, which have to adapt to the vocal range of the singer)

In my opinion, none of these reasons helps you for your decision, and the same holds for the way a considered professional decides.

If are under stress (like in a public performance), you may not be able to concentrate in the same degree as in your exercise room. In that case I would always transpose it first.

Then there are cases, where transposition is really cheap, for example, because the score is already provided in a digital format, which can be transposed by a click of the proper menu option.

In the remaining cases simply try it, so over the time you'll improve in mental transposition.