Band instruments are often labeled as having a specific tuning- such as B^b, E^b, F, C, etc. Each tuning actually sounds a different pitch than the pitch that they are reading on the music. If for example a B^b instrument, such as a clarinet, would play from piano music (C tuning), different notes would sound. For example, a D would sound when reading a C from the music, for an E^b instrument an A would sound when reading a C from piano music. This is why individual scores had been transposed for each instrument in the orchestra. If the music for all instruments was written in C tuning, too many ledger lines would be needed for many instruments and the notes would be too far off the scale. That is why music scores and band instruction books have been transposed for the different instrument tunings. This greatly simplifies sight-reading.

This transposed tuning can cause a problem when buying a tuner since all chromatic tuners are in C key. When the clarinet player, for example, plays an A the tuner will register a B. When an alto sax player plays an A, the tuner registers F^#. This can be very confusing. The chart provided here can be used to identify the transposition of the popular band instrument tunings.