The instruments were held straight down from the mouth and the upper part of the joint was used as a mouth hole.
A variety of different versions of the flute were built. Thus, stretched, curved or horn-like flutes were made, as well as lip flutes, where the mouth hole was attached to the side. During the Baroque period the initial small flutes gradually developed into larger flutes, which were then also used in orchestras.
Basically, there are two types of modern flutes. There are flutes with a conical bore and a cylindrical head, and flutes with a cylindrical bore and slightly conical head.
All flutes from Heckel were built in C as standard. The conical drilled flutes were characterised by a noble and vocal sound, as well as a sophisticated key mechanics, which facilitated the playing of trills. Heckel Böhm flutes, on the other hand, had a rather colder sound, but were characterised by their easy handling and responsiveness. In addition to the regular flute and Böhm flute, Heckel also produced piccolo flutes, terz flutes, Böhm piccolo flutes and the Heckel love flute.
The last Heckel flute was built in 1949.