Most Louis XVI harps of 1770-1800 were staved-back with 7-9 sides,
rather than rounded, with a maple box and a spruce soundboard.
Unlike modern harps, there were round holes in the soundboard, but were
none in the soundbox.
Accidentals were made with seven single-action pedals, attached by
rods in the front pillar to hook (crochet) or pincher
(Bequilles) mechanisms in the neck. In 1786 the forked
disc mechanism was developed by Sebastian Erard, and by 1820 most
pedal harps had it.
Decoration in the Louis XVI style includes an forward-turning spiral at
the top of the pillar. The harp was usually varnished in brown, and had
bouquets of flowers decoration the soundboard.
The sound of these harps provides a transition between the baroque and
classical eras. They had a bright, brilliant and transparent treble,
but a more powerful bass through the use of copper-wound bass strings.
Single-action pedal harps most certainly were not tuned to equal
temperament, so that, unlike a keyboard, on the harp it was possible to
differentiate between D# and Eb, and between G# and Ab.
There remains much to learn about these harps, since few are signed or
precisely dated. I would be happy to advise a study group in this