This clavichord is built according to ideas presented by the Royal Swedish Academy of Science. The scale is Pythagorean down to A, i.e. the sounding string lengths are doubled for each octave. The 4-foot strings also follow the same Pythagorean scale down to A1.

The 8-foot bridge has a flat top for the strings G# - c2, with the strings resting on small pieces of wood perpendicular to the strings and with bridge pins on both sides, making the two strings of the course the same sounding length. Also the hitch pins are positioned side by side so that the string lengths from tangent to hitch pin are the same. This construction can be seen also in N57244 (Johannes Broman, 1756)

There are no string gauges showing the string thicknesses. According to the Academy all strings should have the same thickness. Where the scale is Pythagorean all strings will have the same tension and were supposed to stay in tune with each other even if temperature changes affected the pitch. Variations in humidity, however, play an even greater role in tuning instability and the behaviour of the instrument must have been a disappointment for the Academy.

The Stockholm Music and Theatre Museum has a harpsichord built by Johan Broman in 1756 (N83118). This was the first instrument built according to the ideas of the Academy. As the scale is Pythagorean for most of the compass this harpsichord is very long.