In the 16th century the lip‐reed instruments most commonly used in sacred and chamber music were the cornett (Italian “cornetto”) and the sackbut (Italian “trombone”). The sound ideal described by contemporary writers for these instruments was clearly distinguished from the ceremonial and often military splendor of the trumpet ensemble: the cornett and the sackbut were expected to produce dynamic levels and timbres comparable to those of human singers. The acoustical features, which make it much easier to approach this ideal on the renaissance instruments than on modern trumpets and trombones are explored through measurements on original instruments and modern reproductions.