Brandenburg Concertos been debated what instrument Bach had in mind for the "fiauti d'echo" parts. Nowadays these are usually played on alto recorders, although traverse flutes are sometimes used instead: it is also theorized Bach's original intent may have been the flageolet. In some performances, such as those conducted by Nikolaus Harnoncourt, the two recorders are positioned offstage, thus giving an "echo" effect. Bach adapted the 4th Brandenburg concerto as a harpsichord concerto, BWV 1057. Title on autograph score: Concerto 5 à une Traversiere, une Violino principale, une Violino è una Viola in ripieno, Violoncello, Violone è Cembalo concertato. "Concertino": harpsichord, violin,
Piano concertos by Wolfgang Amadeus Mozart of "fiddling" with all the themes, instead is left with the ritornellic impression: Mozart truly uses "art to conceal art". One further point of great importance is the interaction between piano and orchestra. In the earlier concertos, such as the not totally successful No. 13 in C major, and even more so, perforce, in the concertos for two and three pianos, the interaction between the two is limited, but the later concertos develop the subtle relations between them to a high degree; for example, in No. 16, K. 451. His later concertos are truly described as concertos for "piano and