Investigating the secrets of the violin
The golden age of violin-making harks back 250 years, when the Italian families of Amati, Stradivari and Guarneri of Cremona carved some of the finest musical instruments ever made. Today they sell for millions but what makes these violins sound so powerful? Scientists from MIT have measured hundreds of these Cremonese violins in the hope of unlocking some of the secrets and it could come down to the f hole - the slim opening either side of the strings. Graihagh Jackson's been hearing how...
Graihagh - Nick's love affair with stringed instruments began 10 years ago after a trip to Istanbul. What you can hear is Nick playing the lute. It's similar to a guitar except it has a mere 26 strings and the body is shaped a bit like half an egg. It wasn't until Nick was leafing through a friend's sheet music collection that his background in science and music really came to head.
Nick - I happened to see a renaissance song book that a friend of mine had lying around. On it, I saw a picture of something that looked like a violin that an angel was holding and it didn't have an F-hole on it. I thought, "Hmm, this is interesting." It had more of a C-shaped hole. I thought, could there have been an evolution?
Graihagh - It turns out there was, from a C-shaped hole to an F-shaped hole. F-holes are these slim cousins either side of the bridge in the strings that reveal the innards of the violin. The thing is, the violin complete with F-holes was first designed in 1555 by Andrea Amati. After the Amati family's reign of violin making, there was the Stradivari family and then the Guarneri family. All three families carved out these F-shaped holes. All three families were from the Italian town of Cremona and all three family's designs of violin are still revered to this day. However, by the 1750s, this Cremonese dynasty of violin makers died and with them, their trade secrets.
Nick - For us now, to go back and understand what their methods and approaches were is a bit of a mystery for violin makers as well as scientists. And so, what we're trying to do in our analysis is go back and look at the physical remains and see how they changed.
Graihagh - Everyone wants to recreate the sounds of these famous Cremonese violins, but it's pretty hard. Each violin has its own distinct sound even when building like for like because of the handmade nature of the trade.
Juliet - I'm Juliet Barker. I've been a violin maker for 60 years and I've been teaching violin making to amateurs for 50 years now. I actually play the violo.
Graihagh - So talk me through how you might go about making a violin. I'm sure there are many, many steps involved.
Juliet - Well, there's also many, many ways of doing it. The best job of all of course is choosing the wood and you look at all the pretty maple for the back, the ribs and the scroll. And then you look for a nice piece of spruce to make the front. So, you have to shape a couple of blocks, bend a couple of ribs, and then you've got your outline fixed. And then you can get onto the carving. For us, the things that matter is the choice of material to begin with and then getting the right curves on the outside, the arching, and thickness in the wood, correct for that piece of wood and every piece of wood of course is different. And they're the things that will make the instrument sound good or not.
Graihagh - For Nick, the MIT professor, it was the F-hole that caught his ear. Like a detective, Nick took measurements of 470 Cremonese violins, plotted them against other design variants and...
Nick - One of the fascinating things that we found is that the F-hole length increased from the Amati time period to the Guarneri time period.
Graihagh - And how did that affect their sound?
Nick - Well, what it's going to do is it's going to make instruments with a longer F-holes, more powerful in that low frequency register. What we found going across the Cremonese period, it was about 60% increase in power. And some of the other design changes that we found that led to increasing power was also an increase in the back plate thickness.
Graihagh - This would make sense. Amati violins are usually chosen to play in smaller venues, are quieter less powerful whereas Garneri's violins with their bigger F-holes are known for very powerful and are used in huge concert halls. But why does increasing the size of the F-hole increase its power?
Nick - If you consider what happens on a windy day near a tall building, the wind comes and the skyscraper is obstructing the flow. Well, that air has to escape somewhere. It goes around the skyscraper. So, if you're standing near the base of the skyscraper, you're going to feel it's very, very windy at the perimeter. If you walk some meters away from the perimeter, away from a building, you can find it's a lot less windy and that's essentially what we found. So, if you maximise the perimeter length and minimise the void area, you're actually more efficient acoustically. So, the circle is going to be the least efficient, has the most wide area and the smallest perimeter. And something like the F-hole that turns out has very, very high perimeter and very little wide area so it's extremely efficient.
Graihagh - Does that mean we can now build these sort of optimal violins that are super powerful?
Nick - Well, I wouldn't say that. what we do know for sure is that at these frequencies, we're very confident that these are the effects that are important. How everything plays together and how the coupled evolution with the other frequencies and the other ranges, we can't answer those questions yet. But that's the way science works. It works one piece at a time. and the nice thing about this is that the physical data that we've uncovered from the Cremonese instruments is consistent with basic physics. So, what this has enabled us to do is eliminate a lot of trial and error and guess work, and repetition when you have a physical principle guiding you.
Kat - Music to my ears. That's Graihagh Jackson speaking with MIT's Nick Makris and violin maker, Juliet Barker.
Chris - Indeed it must be Kat because you're a string player, but of harps so slightly different technology there.
Kat - Yeah, I am. Interestingly, yes. I think my sound board of my harp is also made of spruce and I had to take it to be repaired once: it's fascinating going to a harp workshop.
Chris - I'm lucky enough about 10 years ago almost to interview a gentleman from Texas A&M University called Joseph Nagyvary. He was interested in this same question of why these violins from this part of Italy and this segment of history all sounded so good. He had luckily managed to get hold of some bits of wood from some of the Stradivari and Guarneri violins when people send them in for restoration, you get little fragments of wood.
He did some analysis and his conclusion was that the wood had been chemically brutalised by boiling in various copper and iron salts and things because you could still see the chemical fingerprint of that having happened. And they suggested that this had in turn affected the acoustic properties of the wood. Others have suggested that the wood got brutalised in that way merely as a form of kind of insect control because furniture from that period is riddled with woodworm but these violins never are. So, one wonders if that might be part of it too.