Players of the modern bassoon are accustomed to using ornate fingerings to stabilize and correct certain notes that are difficult to tune. These ‘‘auxiliary’’ fingerings open or close tone holes far below the first open tone hole. The primary subject of the investigation was a modern German-system bassoon. Calculations of impedance versus frequency were made using a program based on the Plitnik–Strong model of 1979, with several extensions. The model, in turn, was validated by comparison with measurements taken with a system developed by Keefe et al. The authors also investigated the behavior of auxiliary fingerings on a replica baroque bassoon, and sorted out a puzzling ‘‘feature’’ of a replica Renaissance alto shawm. Based on this work, criteria for ‘‘good’’ note behavior are postulated. [Work supported by the International Double Reed Society.]