Old wood

Instrument Building
#1

So, friends, what is that makes really old wood used in musical instruments sound better, richer, and more resonant? I have read dozens of articles over the years on this and they all offer different and most often conflicting theories and explanations.

It’s interesting to me because once wood has been sufficiently dried and seasoned it’s equilibrium moisture content does not vary a lot (people in America will probably disagree!) and so it can’t really be that, over centuries.

I’d be very interested to kick off a topic on this matter and hear what people know and have to say.

What know is that the spruce family is used for soundboards because it supports a very high velocity of sound and simultaneously has very high cross grain stiffness. Perhaps some long term change in wood characteristics at the molecular level increases velocity and/or stiffness?

In the vast world of violin making discussions, there are all sorts of wild and wonderful beliefs, including one quite interesting one that Strad. and Guarneri used alum to treat the wood, based on some microsampled examples and chemical analysis. Whether this is true I cannot say. and whether it makes any difference I also cannot say.

In our workshop we brush egg white (organic free range only :slight_smile: ) on both sides of the board and I am sure this improves the tone - seems to stiffen at least a shallow surface layer even more.

#2

I am no pro, to be sure. But I’ve made my fair share of harpsichord, both from kit and from scratch, and I noticed a marked improvement in tone if I brush very thin hide glue (ratio 1 glue to 10 water) on the soundboard, both sides, after having glued the bridges and the underside furniture. Just caressing the soundboard just after the glue size has dried lets you listen to a very different sound. In my experience, it isn’t subtle, you can really tell the difference.

I can say nothing about wood-aging. There is a noted harpsichord maker, Bruce Kennedy, who positively uses only ancient wood for soundboards. Of course his instruments are top class, but I don’t know if that’s the reason.

#3

I imagine most reputable makers let spruce dry for a number of years before gluing up a soundboard. Obviously the time required can vary considerably depending on the local climate. Here in Provence the dry mistral wind means that a wood’s moisture content drops rapidly whereas the same piece of wood in a damp British climate might continue to shrink over a period of ten years or so.
I suspect that once inherent moisture content has been lowered then oxydation and consequent molecular change as well as regular playing are paramount in how a soundboard develops. In my experience with lutes, as strange as it might seem, a very old piece of spruce that has been glued up and left for a number of years before being planed down and used for an instrument can take considerably longer to develop sonically than a fresher piece of wood.
I recall some makers referring to the difference in how wood was transported in earlier times as being a possible explanation for it being more convincing acoustically. Many logs of timber were conveyed by river, directly floating in the water and this would have helped clear the sap and accelerate the drying process once the wood had arrived at its destination.
Best,
Matthew

#4

The Appendix C of the Hubbard book is dedicated to extant inventories. For what we are discussing here (wood), I found:

Jean Denis 1672:
Twenty-eight boards etc…

Pierre Baillon 1682:
Several planks of sapin for soundboards

Philippe Denis 1705:
Thirty planks of various sizes both poplar and linden

Nicolas Blanchet 1722:
Six harpsichord soundboards in the rough
Seventy-two planks of pine for making harpsichord soundboards
Fifty-four pounds of ebony in thin sheet
Three bottoms and two soundboards for harpsichords
Ten planks of poplar nine feet long

Francois Estienne Blanchet 1737:
One hundred ninety-six planks of poplar and lime
Seven hundred thin sheet of pine

Francois Estienne Blanchet 1761:
One hundred fifty pieces of rough soundboard wood
Eighteen planks of various woods

Francois Estienne Blanchet 1766:
Boards of soundboard wood
Twenty boards of lime wood
Thirty boards of poplar
Six bosrds of pear wood
Fifteen thin boards of poplar

Taskin 1777:
327 planks of soundboard wood
One hundred ends of wood as much lime as poplar and pine and oak, for harpsichords
12 planks of thin poplar
12 planks of thin pine
A quantity of wood for harpsichord cases
24 thin planks of line wood and poplar
A small quantity of wood for the frames
Several planks of lime and poplar
Several frames and planks

Taskin 1793:
4 quarters of rosewood, each 2 feet 4 inches long
40 sheet of ebony

Hemsch 1769:
56 planks six feet long of poplar
13 curved planks of tge same wood
48 planks ok poplar 6 feet long
2 planks of oak
6 planks of willow
28 bundles of 24 or 25 to the bundle of pine for soundboards of harpsichords (i.e. 672 to 700 boards)
3 planks of walnut
3 membrures of beech

Jean Jacques Malade 1774:
74 planks poplar 6 feet long
21 planks of lime 9 feet long
12 planks of oak
325 planks of soundboard wood

And so on, an amusing reading.
So it seems the makers didn’t store much wood, excepted for the soundboard wood and, to a lesser extent, case wood. The case wood seems to be enough for 5-6 harpsichords, which is consistent with about 1000-1200 jacks some of the inventories record. The soundboard wood, on the other hand seems enough for a lifetime.

Any light from the esteemed pros on the list?

Dom

#5

Mozart’s letter of 1777 describes Stein’s method for preparing a fortepiano soundboard:
" He guarantees that the sounding-board will neither break nor split. When he has finished making one for a clavier, he places it in the open air, exposing it to rain, snow, the heat of the sun and all the devils in order that it may crack. Then he inserts wedges and glues them in to make the instrument very strong and firm. He is delighted when it cracks, for he can then be sure that nothing more can happen to it. Indeed he often cuts into it himself and then glues it together again and strengthens it in this way … "

In recent times small-scale piano rebuilders used a clever shop-made hygrometer using a strip of spruce to measure low levels of humidity. It turned out that with repeated cycles of humidity change, the wood strip became less reactive to rising humidity.

#6

Thanks Ed! Now I know where the stories I have heard of exposing soundboards to snow came from. I was trying to remember.

Exposing them to all the devils no doubt is the technique that contemporary makers are missing. :slight_smile:

#7

And so. Torrefaction. This has become a trend with guitar makers, large and small. Supposedly ages the wood rapidly. Any truth in it?