Some musicians have a hard time figuring out note names for transposing instruments. I’ve found this two-step process helpful:
- Take a transposing instrument in the key of [X].
- A concert [X] is a written C on that instrument.
A real-life example:
- The tenor saxophone is a transposing instrument in the key of Bb.
- A concert Bb is a written C on the tenor saxophone.
- The alto flute is a transposing instrument in the key of G.
- A concert G is a written C on the alto flute.
This doesn’t solve every transposition issue, but it can help us keep our note names straight.
Necessary disclaimer: The main problem this doesn’t solve is octave displacement. The trumpet and tenor saxophone, for instance, are both transposing instruments in the key of Bb, but the trumpet is written a major 2nd above its sounding pitch, while the tenor saxophone is written a major 9th above (P8+M2).
Likewise, double bass and tenor voice parts are often written an octave higher than they sound. They are considered transposing instruments, even though they are in the key of C. There are also related issues of instrument range, changes in timbre and instrument registers, etc. that go far beyond note names.
If you are concerned only with note names, you can safely use the two-step process above. If you need the correct note names in the correct octave, you will need to know the transposing interval and then make the calculation (e.g., concert Eb4, transposed for Bb tenor saxophone, is F5. [Eb4 + P8 + M2 = F5]).