http://www.ars-nova.com/Theory%20Q&A/Q145.html Why are there transposing instruments?Question: I don't understand why we have transposing instruments. If a trumpet is playing a C it is sounding a Bb. Why not call it a Bb and write it that way? (Similar to the bass clef instruments.) - CarlAnswer: I'll bet that question is asked by a great many people.Here I cannot rely on first-hand knowledge, s..