Dec 30, 2012

Violin Modifications by Rowell & Siders Luthiery

I'd like to explain a little about the process of "tuning" the body of a violin. In previous posts I eluded to this process but didn't go into much detail.

Using the following techniques can turn a $200 violin into a $2000+ violin. The good thing is that you can get a very fine violin that is 90% finished for very little money. The bad thing is that it still takes about 10 hours of complicated work to get that 10 fold increase in quality.

The cost of making one from scratch is a thousand dollars and as many hours of work. The obvious option of just buying The 'Lady Blunt' Stradivarius of 1721, currently the most highly valued violin in the world (almost $16,000,000) is beyond the scope of this article, and the budget of anyone I know personally.

  In this particular case, the violin was a pawn shop Chinese violin made of good woods but mass manufactured and with very poor sound quality. All the musicians that tested it for me mentioned it's "tinny", "flat" sound and poor playability (difficulty in avoiding the dreaded "screech").

Standard wisdom dictates that overly thick top and bottom plates are probably the culprits. This makes it a good candidate for improvement as overly thin plates cannot be made thicker (ideally).

First the violin was disassembled, the front, back, neck and finger board removed. We then test the front and back plates against traditional specifications for thickness, weight and most importantly tone.

Two techniques are used to evaluate tone.

The "tap tuning" method entails recording the sound of the wooden plate with specialized recording software while tapping it with a mallet (not too hard ).

The other, more in depth method is called "Chiladni patterns" (a complex procedure where sound waves are injected into the plate causing granular material to form patterns at certain frequencies).

The tapping technique tells you how much material needs to be removed. The Chiladni technique tells you where is the best place from which to remove it.

It sounds very scientific and definitely outlines what would otherwise be a completely nebulous activity. But it's hardly an exact science. Ultimately there is what's considered "best", what's achievable with the particular pieces of wood, and what your client personally likes.

There are guidelines as to what the targets are: higher pitch for a solo instrumentalist (i.e. bluegrass) and lower pitch, ostensibly for beginners and easy playability.

The higher pitch makes it a little louder but also requires greater control from the musician to get a good tone. The lower pitch sounds warm and mellow by comparison, is slightly less loud, but the whole instrument resonates more easily with the bowing of the strings.

Aside from volume, this distinction is strictly subjective. I'm more partial to the melodious violin so that's where we set our targets for this one.

Once your targets have been set and your starting points established, the wood it's self presents limitations as to whether those targets can be reached.

For example, there are two important tones for each wooden plate, and the relationship between them is critical. But changing one also changes the other, you have two moving targets to shoot for. The proverbial "herding cats" scenario.

For another example, you many need to remove wood to lower a tone, but the wood is too thin already. Removing more wood, making it thinner may risk breaking. You have to balance all these factors to get the best out of what's available. It's a juggling act!

There are many other steps in getting the violin back together again once this critical tuning step is complete. The position, shape and tuning of the bass bar on the top plate, alignment and position of the neck, and fingerboard, fitting of the front and back plates including new linings for this particular violin. (the Chinese factory used some kind of soft spongy linings, more like cane than wood).

The bridge alone is a very involved step as it has to be fitted exactly to the violin to match the neck angle and curved top plate. And finally the setting of the sound post, by far the easiest step in improving a violin's sound.

Hear Jim Hughes play the violin we've just described here.

We always use the traditional hide glue for all parts so that the pieces can be disassembled in the future for further repairs. It's far more difficult to assemble with hide glue compared to the ease of using modern synthetic glues. But the modern glues don't soften with heat, so when a repair is needed, even more damage is done trying to get them apart.

Instruments get better and become more valuable with age. Hyde glue insures it will be repairable and ever more valuable hundreds of years from now.

So that's a very brief description of how we fine tune a violin here at Rowell & Siders Luthiery. Give me a call if you'd like an evaluation of your violin (or mandolin).

Rowell & Siders Luthiery
Keith Rowell

Example of Chiladni patterns on a violin back.

For those not yet bored by the subject, here's a little more detail of the most crucial step.

In the Chiladni patterns, mode 2 and mode 5 should ideally be one octave apart and tuned at a particular note (see video). You adjust the notes lower by removing wood, (going higher is not an option, it's a one way street). Let's say the modes are too far apart, you can't raise the lower one, so the upper one has to be lowered to bring them into harmony.

Now in doing so, you want to make sure you don't fall below the ideal set by historic standards. It's not just how much wood is removed either. From where the wood is removed dictates which mode is modified the most. Remove wood from the wrong place and a mode that is already too low becomes even lower (thankfully, the Chiladni patterns exercise defines these areas pretty well).

Once you've mastered how to achieve these goals, the fine art is to discern what a violin needs and the least invasive way to achieve it.

All of this however doesn't even begin to scratch the surface of the long standing debate of 440hz vs 432hz historical orchestral standard for the note "A". Some subjective judgement is required.

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