Judging Wood's
Acoustic Merits
Taptone Testing
In the Appalachian dulcimer, both the top and the back influence the voice quality. The top is by far the most influential, but the back's quality can modify the voice also.
To judge a back or top for its qualities, we tap it. To tap it properly, do this:
- Hold the piece to be judged about a fifth of the way down its length, suspended between thumb and fingers.
- Now, hold your ear at the edge (you won't be able to get the right effect by listening to the sounds coming off the face)
- Gently but firmly rap on the wood. Find the place where your tapping hits so that there is minimum wobbling when you hit (if you are familiar with baseball, you will know that there is a "sweet spot" on the bat where it wants to be hit – same thing here). Experiment with tapping above and below that spot, listening for differences in the sound of the wood.
- Notice whether the wood has a "tenor", "baritone", or "bass" general character. Also notice whether there is a separate ringing tone which persists while the first response is dying out.
The resulting sounds tell the experienced ear what the resulting instrument will sound like. For instance, if we are designing a well-balanced yet mellow teardrop, we will find a back which has a baritone/tenor tone, and a strong ring in the tenor region. We will match that back with a redwood top which has a rich bass/tenor or bass/baritone. Depending on the exact matches we get, we may further match the two for specific harmonic relationships. We might, for instance, want to augment a baritone/tenor top with a loud tenor ring by selecting one which is a third or fifth below the tenor ring of the back.
After a top and a back are chosen, these qualities, along with notes about grain character and figure, are written in the Bear Meadow Tonewood Log. This log contains an entry for every instrument built at Bear Meadow. After each instrument is completed, it is checked against the original judgment of what kind of instrument voice was predicted for these woods. That final assessment is also noted in the log, so that the experience gained with every tonewood assessment is captured for later reference.
