The sound of the harp is generated by the vibrations inside the soundbox: mostly from the soundboard, and to some extent from the body.
Soundboard Wood
The soundboard is the soul of the harp. It receives the vibrations from the strings to amplify, and the quality of the sound and its resonance depends on the soundboard. The main wood is spruce, because it has an excellent balance between strength and suppleness, allowing a very good return of the vibrations.
Body Wood
The body wood subtly influences the harp’s sound. It is chosen according to criteria like solidity, and then for its aesthetic qualities. Generally, plywood is used (wood stuck together in numerous fine layers) for the neck and the base (the strings can cause up to 680kg of tension in concert harps), and plain wood for the column (which is not placed under so much tension).
Woods for finishes / Varnishes
Often, a fine veneer of higher-grade wood is used on the body of the harp. This has no effect on the sound. One model of harp (made of the same wood) can have several different finishes. Soundboards are rarely veneered on concert harps, because this would adversely affect the sound. Different colours of varnish are also used, and also painting (more rarely on the soundboard).
PLYWOOD VS SOLID WOOD
When you play a note on an acoustic instrument, this produces several sounds:
The fundamental frequency of the note, as well as the harmonics that surround it
(closely-related frequencies which add to the complexity and warmth of the sound).
Plywood
Used for the soundboard and body of most harps.
• Material made by sticking fine sheets of wood together. Often, only the exterior sheet is of fine wood, for aesthetic reasons. • Projects many core notes but fewer harmonics: it gives a powerful sound, but with less warmth and richness than the sound from plain wood. • As the wood is fixed by glue, there will be very little improvement with age. That said, if the harp sounds good in the first place, you can be assured that this will hold well.
Solid Wood
Used for columns and some soundboards, but rarely for the neck or the soundbox.
• A single piece of wood from the tree trunk. For soundboards, sometimes cut down the middle and stuck together following a butterfly principle • Projects a lot of core frequencies and harmonics, gives power and more richness that the sound from plywood • Transmits vibrations better, and they can resonate freely in time. As there is no glue, the sound continues to get better throughout the instrument’s life.
Spruce.
The Wood Of Soundboards.
These are the three types of spruce most commonly used.
Spruce has been the preferred wood for soundboards for hundreds of years. This applies to the soundboards of harps, pianos, guitars and violins.
It gives a very clear sound, crystalline in the upper register, combine a lot of sensitivity and a sweet, pleasing timbre. It responds to the slightest touch.
On the harp, the choice of body wood has little impact on the sound. Nonetheless, harp makers and harpist generally agree on the following sound specs:
Spruce being the wood most commonly used for the
soundboard, you will find below a selection of the woods used
for the body and finishes (and rarely for the soundboard).
Note: The big brands use mostly beech and maple for the body (and other woods for finishing). Independent luthiers use other types of wood more regularly..