Tin whistle
In recent years a number of instrument builders have started lines of "high-end," hand-made whistles, which can cost hundreds of dollars US each — expensive in comparison to cheap whistles, but nevertheless cheaper than most other instruments. These companies are typically either a single individual or a very small group of craftsmen who work closely together. The instruments are distinguished from the inexpensive whistles in that each whistle is individually manufactured and "voiced" by a skilled person rather than made in a factory.
Physics of whistles
There are a number of whistles that possess the characteristics of both monopole and dipole sound sources. In several of the whistles described below, the driving source is dipole (generally an edge tone) and the responding source is a monopole (generally a tube or cavity in proximity to the dipole).