Thursday, May 26, 2011

My Tonewood

I have a special relationship with my tonewood. Many pieces are like old friends. I go back to visit them each time I peruse my wood collection, choosing materials for an upcoming commission. In fact, I prefer a certain amount of my work to be un-commissioned ... in part because I can through my wood and decide the time has come for a certain piece, even when there may be no standing order for it.
The piece I'm holding below is an interesting case in point. I got a call from a contact in Bosnia that scouts wood for me. A beautiful curly maple tree had been found high in the mountains. 

This week, time has finally come for one old friend. I will build a personal model violin and make it available to someone who would like a part in the next chapter of its long future.
I flew over to Belgrade and went up into the forest to have a look at this tree. It was spectacular! Large enough for many cello backs! However, there was a problem. The downhill route out of the mountain led through Bosnia-Herzegovina and it would have been impossible to move such a trunk uphill to the road, even when cut into 3 foot lengths. So we had to split the wood in the field and with curly maple that was a real pity as the yield was greatly reduced. You can still see the scars from that day on the piece I am holding. Nevertheless, I got a wonderful supply of maple that now beginning to use.
Piles of top wood. Although maple is more costly, the contribution of spruce to the final sound of a violin is far more dramatic! I have piles and piles of spruce, sorted according to various qualities that I feel are important.
The thing about wood is that 'speed of sound' is only half the question. What if the sound is pretty fast but the wood is also heavy?? In fact heavy, stiff wood is often quite fast. The speed comes from the stiffness ...think of bow wood for example. I want top wood that is maximally fast while also being maximally light ... low density. Some makers look only at density, but this too is only half of the story. What about super light wood that is punky and weak?? i.e. the opposite of bow wood? Not so good either, if you follow me.To really nail this question, you need an equation that takes both factors into account. This so called "Figure or Merit" actually exists in engineering terms and, luckily for us, a formula for tonewood is out there, albeit little used in the violin making world. It is calculated as the suare root of the speed of sound (along the grain x across the grain) divided by density. The higher the result, the lighter my top can be for the same target tap tones and modes. I find lighter weight plates are generally more responsive and give higher sound amplitude for the same amount of energy put in. Oliver Rodgers wrote a Fortran program for calculating the Figure of Merit in pieces of wood. And, my friend Thomas King re-worked it as an Excel spreadsheet which he shares on his web site.

This piece of wood will become GA203 later this summer. A violinist in the Euclid String Quartet has been using my violin for some time. Now the other Euclid violinist, Jacob Murphy, will be joining him.
When a big piece of wood is roughed out, some internal tension is released and altered as well. So I prepare my blanks ahead of time and let them rest and move. The square notches in the top piece are not just for the joining clamps. By cutting them ahead of time, the top moves less when the final outline is completed.
I like to talk to my clients about their wood. We send pictures back and forth in order to include them in the creative process. But players come to me for more than just pretty wood. Its like going to a famous tailor for a custom made suit. Everyone can sew straight and buy fine cloth; that is assumed. You go to a tailor that will make you look good!

I educate my clients about wood because I want the instruments they sponsor to make them sound incredible!!!
This set of wood was prepared for a client in England for whom I am building a personalized Stradivari. After reviewing some photos, he wanted to swap the back with the one shown below. This one won't be wasted. It's a bit playful, but I really like flipping down one side of a flitch a one piece back. So I will finish it as a personal instrument, following some new ideas that are on my mind this summer.
Work underway today, roughing out the arching for the new back.
It's the same wood, from the same tree. But the flames slope upwards from the center joint, like the Betts.
A few hours later and Dr. Winter's GA204 is back on schedule.

Dear Friends,

I'm off to Prague on Monday for a meeting of the Entente Internationale des Luthiers et Archetiers (EILA). I will be representing my American colleagues as the US delegate and presenting a talk about "Trends in Today's Violin Making". Stay tuned ... I'll send photos back to the shop to tell you about the trip next week!


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