Sunday, May 29, 2011

SOUND POTENTIAL

Sarah Mnatzaganian of Aitchison & Mnatzaganian, the English cello specialists, asked me some questions for an article she is writing. ( She and her colleague Robin Aitchison, have organized a number of exhibits of contemporary cello bows.) Sarah’s questions have to do with the sound a bow generates on an instrument and they are good questions that nearly everyone wonders about.

Sarah: What makes bows sound so different?

Bows of course do not make sound themselves but they accentuate different ranges of an instrument’s potential sound spectrum as well as simply mobilizing more or less sound from the instrument. There are a number of elements contributing to the bow’s sound generating potential. First and foremost is the wood. The wood’s density, it’s grain structure, presence of perturbations in the grain, it’s stiffness and the quantity of extractives such as pigments and waxes in the wood can all effect the sound. Secondly there is the bow’s structure; it’s camber, it’s graduations or diameter from tip to butt, the height of frog and head, weight of frog and winding. Of course the qualities of the wood are reflected in the bow’s structure, strong wood will permit finer stick diameters for example. In addition the quality and quantity of hair has an effect. All these qualities of wood and structure are combined in an infinitely variable way in a given bow. The response of different instruments to this bow also varies, although certain qualities such as brilliance tend to be consistent.

Sarah: As a maker, how much control do you have over the sound of a bow during its manufacture? (for example, if a player asked for a bright sounding bow, would you be confident of fulfilling his/her request?)

As a maker one can definitely affect the bow’s sound generating potential. It helps greatly to have a stock of wood from one region that one comes to know over the years through trial and error. For instance when a stick from a particular board has certain qualities one can assume the sister sticks on the same board will be similar. Also one associates a certain look in the wood to a certain result. In the same way through experience one associates the mass of the frog or the amount and type of camber with a certain result. Brilliance in the sound can be achieved through choice of wood and other physical traits one puts in the bow.

Sarah: What makes the tone of some bows so much more interesting/complex in tone colour than others?

Richness or complexity of sound is a result of matching the right stick and the right dimensions. Once again we are beholden to the wood. There is always some magic to the overall sound signature a bow can produce; there is no simple formula and the maker is inevitably going to use their intuition as well as their knowledge. When players use poetic metaphors like ‘chocolatey’ or my favorite, ‘buttery’, the maker is going to mine all their experience to dig a stick out of their stocks that simply feels right in addition to having qualities that in their experience will produce the desired result. The instrument the bow is destined for is a large part of the equation as well.


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