Among other things, the balanced sound of Hey organs is founded on the painstaking care that goes into manufacturing each and every organ pipe. Larger instruments may well include thousands of wooden or metal pipes.

Only select domestic rare woods, such as oak, fir, pine, basswood, and various fruit-tree woods are used. Hey's extensive and well-stocked store of wood represents tremendous capital. Here, the increasingly rare, high-quality woods are available in sufficient quantities that have been stored naturally under optimum conditions.

The metal pipes are manufactured with  adequately dimensioned wall thicknesses, according to old formulas, from tin and lead alloys. Manufacturing technology, various standards, and the calculation of the scales are closely guarded trade secrets.

Hey organs have a clearly arranged tonal volume that is continuous even in the low fundamentals. To an organ expert, the balanced voicing shows the tradition, influence of and bond to the regional organ landscape, to the Rhoen, the Fulda region, Franconia (Main), and Thuringia.

The basic character of the Hey sound, which is founded on regional tradition, always remains recognizable, although every single instrument is voiced for the unique acoustics at the place of installation.

Hey aims to produce instruments that fulfill the demands of the liturgy and divine service while being equally suitable for use in concert, as a solo instrument or for accompanying choral works.

This versatility also applies in a historical sense, so that any era of organ literature can be brought to life on a Hey instrument. The great works of Johann Sebastian Bach sound just as good as compositions from the 19th or 20th centuries, for example, works by Franz Liszt, Max Reger, or Olivier Messiaen.