In a major scale, all notes A-G, no matter sharp or flat, are expected to appear exactly once. I only just learned this, but it has to do with how the notes get named out. Nobody likes seeing double sharps in a key signature. So if you're writing a piece that could be in F# or Gb, and you're going to include an alto sax, they'll be looking at either three flats or nine sharps (yes, nine - double sharps on the F and G).įlat keys are preferred for any piece that includes the transposing instruments. And the Eb instruments like alto sax or alto clarinet are going to need three more sharps, or three less flats. When a C is written, Bb sounds - so they need two more sharps or two fewer flats. As a consequence, French horn music will have one more sharp (or one less flat) in the key signature to sound the same as the C instruments.Ĭlarinets, trumpets, and tenor saxophones are 'in Bb'. But not all instruments are C instruments.įrench horns are 'in F' - when a C is written, an F sounds from the instrument. If you're writing for only 'C instruments' (which produce a C pitch for a written C, even if that pitch is in a different octave) there's no general preference. The keys of F# vs Gb are a toss-up: you have six altered pitches either way.īut the second consideration is the one important to your question, because you mentioned clarinets - they're a transposing instrument. You'd prefer B over Cb because the key signature will have five sharps instead of seven flats. In general, Db would be preferred over C#, because your key signature will have five flats instead of seven sharps.

But there are two things to consider.įirst, the number of sharps or flats in the key signature. In equal temperament, the keys are equivalent.

C flat major key signature