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 whistle phenomena in which heat plays a role. The temperature in a sound wave varies, but since it is so small normally it is common to neglect its effects. When amplification can occur a small variation can grow and have important influence on the sound field created. The most well known thermal whistle is the Rijke tube. Peter Rijke placed a heated a gauze material inside a vertical tube.