Jon Page inquired in Digest 970924 about a new invention for the piano,
the harmonic mechanism.  The following is a translation of part of the
article posted at the web site listed.  Many thanks to Jon Page, Jan
Kijlstra, and Robbie Rhodes for reviewing the translation, and to Daniel
de Rauglaudre for posting a sketch of the mechanism.

If you would like more information, please write to the inventor of the
pedal:

        Denis de La Rochefordiere
        18, Avenue Balzac
        F92410 Ville d'Avray
        France

Joyce Brite
brite@ksu.edu       http://www-personal.ksu.edu/~brite/


 [ Translated from the French by Joyce Brite.  Abridged for MMD. ]


WORLD PREMIERE: A NEW PIANO SOUND IS DISCOVERED
    (http://pauillac.inria.fr/~ddr/piano/)

The Harmonic Mechanism: A New Sonority for the Piano

On March 17, 1997, you will discover a previously unheard piano sound.

Four renowned artists --  Anne Queffelec, Huseyin Sermet, Martial Solal
and Georges Pludermacher --  have agreed to play together at the
prestigious Theatre des Champs-Elysees for unveiling the possibilities
of this new instrument.

The harmonic mechanism, which was made specifically for this new
instrument, is the fruit of ten years of research by its inventor, Denis
de La Rochefordiere.  It consists of a revolutionary system of dampers
activated by a fourth pedal, which adds to the function of the usual
three pedals, modifies the pianos tone, and permits superimposing a
sonorous plane.

Musical contribution of the harmonic mechanism:

The harmonic mechanism was born from one fact: in the modern piano, with
its sonorous power reserve, the dampers are applied [to the strings] very
efficiently, which has the effect of restraining all the resonance of the
piano even though the loud pedal is not utilized.

It is very difficult to allow staccato play while utilizing the loud
pedal.

The contribution of the harmonic mechanism is revolutionary in that it
allows staccato play while maintaining all the dampers raised with the
exception of the notes played, which are suppressed by relaxing one's
touch.  The listener then notes a reverberation which enriches the
phrase. ...

 [ The patent drawing shows how this is accomplished.  Using the fourth
 [ pedal the pianist can lift all the dampers from the strings, but when
 [ a key is subsequently pushed, the connection to its damper is broken,
 [ thus that key-damper functions normally and damps its strings while
 [ a staccato passage is played.  -- Robbie

"Descriptive Technique of the Harmonic Mechanism"  (see sketch)

Damper release:

In a traditional grand piano, the loud pedal controls a hinged bar, which
raises all the dampers simultaneously.

 [ The numbers in the following passage refer to the patent drawing at
 [    http://pauillac.inria.fr/~ddr/piano/mecanisme.html

In the piano with the harmonic mechanism there are two hinged rails: the
loud rail (112) which raises the damper rack (104) collectively, and the
harmonic rail (111) which acts on the dampers as an intermediary on the
release rack.  Each release (14) is mobilized around an axis (30) which
provides an engagement with the harmonic rod and an end in contact with
the key.

*  When the harmonic rod is put in action, all the dampers are raised,
releasing the resonance of the wires.

*  When the play is brisk, it acts then in making the release pivot,
which allows the corresponding damper to fall back on the wire with the
relaxation of the touch, thus interrupting the note played.  The
resonances of the notes, in sympathy with the 200 wires, are freed from
the remaining dampers, enriching the quality of tone of the piano.

The "push rods":

The two bars of the mechanism are activated by a progressive mechanism
of push rods (5 + 19 + 20), which coordinate the displacement of the bars
along a determined movement.  Pressing the pedal more or less gives the
reverberation by sympathy.  When the pedal is completely pressed, it
maintains the notes in resonance although there is action on the
keyboard, like the traditional loud pedal.

The lyre has the three traditional pedals, with a fourth pedal isolated
to the right which controls the harmonic mechanism.