The Sound of Wood

Have you heard?  You mean, when building a cabinet you haven’t sometimes been aware of a ping here, a plunk there? No, it’s not the heater expanding. It’s your wood . Wood is sensuous. We gaze on its beauty; we relish its aroma; we delight in its texture .

Taste is not important, unless you happen to be a termite; but sound can have its place-though that is certainly not the first consideration in selecting lumber. Listen up .Good Vibrations From resonant redwood to tinkling teak, the sound of wood begins with cells. Their length , the direction in which they grow relative to the vertical axis of the tree, and the ratio of the different thicknesses of their walls comprise the wood’s elasticity.

This causes vibrations when the wood is hit. It works like this : When wood is struck by an object (for example, a hammer missing a nail) , that section of wood becomes deformed. Its elasticity, however, will cause it to try returning to its original shape.

But because of excess energy from the blow, the wood will continue to bend up and down (vibrate) until all the energy is lost.

While vibrating, the wood is transferring energy into the air. This air energy takes the form of sound waves, which reach our ears as sound, or pitch . Due to their individual cellular makeup and elasticity, therefore, different woods have different sounds. So? Familiarity with the different pitches of woods can benefit you in your woodworking. Say a customer wants a good solid sound when he closes a cupboard.

Or a whisper for a bedroom door. Becoming attuned to the various pitches of wood will help you know which to select.

Other applications include door knockers, drawers, wood chimes, gavels, toys, special effects, dance floors and musical instruments.

Anywhere one piece of wood is hit by another piece of wood or object. Building a Pitch Detector To hear the ocean, listen to a seashell. To hear the pitch of wood, build a xylophone. (“Xylon” is Greek for “wood”;”phone” is Greek for “a sound.”) To build this detector of wood sounds: cut 5/8″ x 3/4 x 9″ sections of the different species you want to chart. The sections should be quarter sawn and clear of any knots.

Next cut four lengths of dowel sized so that your samples can lay across them with about Ys” in between . Figure in at each end of the dowels so that they can be fitted into the uprights that will serve as legs for the xylophone.

Drill holes in one end of each section for a screw to mount them on top of the dowels. Make the holes oversize and don’t tighten the screws all the way so they won’t dampen the vibration . Glue a layer of felt along the dowels before attaching the samples. Rank the species in order from the lowest to highest pitch by using a small , round , wooden mallet. Hit the bar directly in the middle and chart the pitch numerically with I being the lowest. (l have found willow to be I; cherry 2; oak and maple 3; pine and walnut 6; alder 10.) Sound good? With your xylophone and your knowledge of wood pitch, you and your maple will soon be making beautiful music together review