Sound and Range:
The dimensions of the pipes and the lip have been so designed, that the commencement of the note (the attack or "chiff") and the sound of the pipes are not affected by the movable beards. Using closed pipes, the range is two chromatic octaves, from g to g2.
By means of a special mechanism with movable beards on the flue pipes, each individual note can be tuned precisely. Each pipe has movable beards on a vertical axle. Each key, and therefore each pipe, has a slide which moves these beards via a lever mechanism. A replaceable plastic sheet, on which the position of each tuning can be marked, is mounted next to each slide.
The movement range between open and closed lips, that is the pitch variation produced by these tunable pipes, is approximately ± 25 Cents (100 Cents = one equal-tempered semitone).
In order to reproduce historic temperaments, the instrument has two alternative semitones in each octave: D sharp and E flat have separate pipes, as do G sharp and A flat. The keyboard has split keys for these notes.
The instrument has a removable modular air supply, with a choice of electric air pump or manual bellows. Manual bellows should be prefered.
The exterior of the instrument is designed to show the proportions of the musical intervals. For example, the height of the left side and the depth have the proportion of an octave (2:1), the height of the left side and the height of the right side have the proportion of a fifth (3:2), and the height of the right side and the depth have the proportion of a fourth (4:3). Numerous intervals are thus visible on the instrument, which has been developed partly for the purpose of teaching the perception of pure intervals.
Dimensions: height approx. 90 cm, width approx. 80 cm, depth approx. 45 cm (with bellows approx. 90 - 120 cm).