Cello Restoration

Repairing An Inherent Tonal Problem.

In late 2011, an instrument came to us with the following story: it had been acquired new by a professional cellist in 2005 from an experienced maker and possessed a sound that she liked enormously. A year or so after the purchase the sound deteriorated noticably, and no set-up combination seemed to correct that. Some time ago she took it to a luthier who put a small soundpost patch in the cello, a bit thicker than the graduation there, apparently in an attempt to add/change the wood in this critical area. It helped minimally but the cello was still a considerable distance from how it played initially.

We took a long look at the cello, played it, and tried various string and tailpiece combinations. Melissa, Rob, and I all felt that the cello had a weak sound: thin and whiney in nature. It had many of the symptoms of a top that had been made on the thin side, including the initial good sound followed by a thin, weak tone that can come from a piece of wood whose “spring” has worn out after a period of time.

A close look at the cello told us that the instrument had been very well-made and nicely varnished: it was a wide model with somewhat flat arching. A thickness gauge revealed about 4.4mm at the thickest part of the top near post: possibly sufficient for a narrower, higher arched model, or at least for a much stiffer piece of spruce, but apparently not here. Pushing down with a finger depressed the top much more easily than we would have liked. A further complication may have been the bassbar which was smaller than usual, especially for the type of top (wide, thin, flat, flexible) on the cello, and also made from a grade of spruce surprisingly low considering what had gone into the rest of the instrument.

After discussing first among ourselves and then with the owner, we arrived at the following repair.

We would remove the top, remove the bassbar, fit a new thicker and taller bassbar made of much better wood, then add stiffness and mass to the top by strategically fitting and glueing 60 mm X 14 mm cleats in a pattern so that they would overlap in a way that would not invite a crack between rows of them. The cleats would be concentrated more in the belly area of the top leaving the flexibility near the rim in tact (see photograph). Note that the cleats had to be glued and shaped before the bassbar was installed; so the bassbar was fitted and eventually glued over the cleats like it would be in the event of a repaired bassbar crack. This allowed for a uniform addition of stiffness and mass throughout the belly area.

It is worth noting that none of what we did was irreversible or affected the integrity of the maker's work. We took nothing away from what was original; everything we added could be removed, another bassbar could be installed (bassbars, like necks {not pegbox/scrolls} and fingerboards are expendable and do not influence the inherent value or integrity of a violin-family instrument) and it would be effectively the same as the original.

Though the jury is still out for the long term - it's only been a month in the owner's hands – the initial change is dramatic. There is a noticable power, complexity, and roundness that were not at all present when it came into our shop, and we can no longer easily depress the top with our fingers.

It is our opinion that the luthier who put the soundpost patch in was of the same opinion – there was too little wood and therefore too much flexibility in the top. The owner is very pleased and the overall cost was considerably less than other solutions she had considered – new top, large chest patch - to name two.

The success of this repair gives hope for instruments that have been either initially made too thin, or overly regraduated.

December 4, 2011

Paul Perley

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