Tap Tone Tuning Instructional Guide, (C) 2009 David Langsather

(Revised 9/2009)

...Much has been written about tap tones over the years but I believe that this instructional guide will help you make sense to the technique so that you can use tap tones with confidence to make the necessary small adjustments that make a violin family instrument come allive and become pleasing to the ears of both player and listener.

.... A few words about tap tones on wood might be useful. For example, if we tap the center of a piece of violin plate stock (before it is carved and shaped) with our knuckle, and record the sound with a condensing microphone and a computer-based sound analyzer, the sound spectrum would look like figure one.

Figure One

You might practice hearing the fundamental tone by listening to orchestra music and selecting only the notes of the double bass during the performance; in other words, a key skill necessary for using tap tones for tuning stringed instruments is to train our ears to hear the lowest fundamental part of the tap tone sound spectrum when needed.

I believe that this sound chart illustrates a major difficulty in harnessing tap tone tuning as a useful tool for instrument making and adjustments: Our ears more easily hear the higher frequencies, so we must listen closely to hear the equally important 'fundamental' (low) tap tone.

...When we start with a solid block of violin making wood, such as a neck block, or spruce block before we begin to carve out our violin, tapping on these pieces of wood will yield a tap tone spectrum such as drawn above. However as we begin to shape and thin the wood to useful size, the range of tap tones (from highest to lowest) begins to widen and we can hear definite high and low tones to the tap if we listen. When the wood is to instrument thickness, the range of tap tones is large. The main rule to remember is that as the fundamental tap tone gets lower (as we thin the wood section), its high overtone goes higher as the same time (that is its range of tap tones increases).

...On the next page I will describe how to use this information with two pencils as our tapping tools.