In our last newsletter, I wrote about backboards and what they do. I suggested
indicated that there are basically three categories of backboards (from a functional standpoint): resonator, closing (lid), and sound producing. Mandolins feature sound-producing backboards, and getting them to produce the ideal tone is a critical element in the construction of a mandolin.

One question that comes up often is "what affect does wood figure have on tone?" Actually, the figure in and of itself, has very little affect on tone. I say "very little" because the figure doesn't affect a wood's density and mass. However, it can affect a wood's stiffness. A piece of maple with curly figure is a board whose grain is irregular. The irregularity is seen as wavy grain when viewed from the side and is the result of that segment of the tree sagging from its own weight. The curly figure in maple occurs under heavy limbs and along sides of the trunk where the tree is sagging badly to that side. Hold you hand up, palm towards your face, and then bend your hand down. Notice how the skin at your wrist wrinkles up. That's what happens to a maple tree that is heavily laden. As a result, the irregular wavy grain makes that piece of maple more spring-like, which translates into wood that is more supple. This is a good thing for backboards and a bad thing for necks.

The important part of the answer to the questions above is that it is not really the figure per se that has an affect on tone, but the wood that hosts that figure. For example, bird's eye maple is a figure that only occurs in Sugar maple (Acer saccharum), which is also known as hard maple or rock maple. Sugar maple is very heavy and dense (the heaviest and most dense of the Acer family) and as a result, it produces a very hard bright tone that lacks bass- and mid-range response. Quilted figure only occurs in Big Leaf maple (Acer macrophyllum). Big Leaf maple is among the lighter and more supple of maples. As a result, it produces excellent bass- and mid-range response. Curly figure occurs in all maples (in fact, it occurs in all woods, from those as light as pine to those as dense and heavy as ebony). The curly figure in Big Leaf maple is typically more "flame" whereas the curly figure in Sugar maple is more wispy and stripe-like.

So, it is really the density and suppleness of the wood that has the greatest affect on tone, not the figure. Several months back, I showed you this photo of a mandolin that Kali and I made. She selected California claro (a species of walnut) for the backboard and rim, and then she chose a highlight color on the rim for me to match when coloring the soundboard. Claro walnut (and other walnuts) is an excellent wood for mandolin backboards because it is so light and supple, and this instrument really sounds great.

Luthier Robb Brophy (Elkhorn Mandolins) has experimented with several unusual woods for backboards. Not only does he finish them beautifully, but he is very focused on preparing soundboards that complement the tonal attributes of his backboards using combinations such as cedar soundboards and cocobolo backboards like this one pictured here.

Regarding the final steps of adjusting a backboard so that it performs properly, I can't say enough about tap tuning - I know this is something you hear about a lot from me. Tap tuning is a subject and process that I consider to be very important and is, in my opinion, the key to success in building instruments that sound great and produce consistent tone, instrument after instrument. We prove it every day in our shop (and Campers get to experience it during our Luthierie Camps). To help you understand tap tuning better, Kali will be posting (in about 3-4 weeks) a short introductory video on tap tuning to our Facebook page and YouTube. In that video, I show some of the tools used in tap tuning, and I demonstrate tuning the tone bars on an F5 mandolin. It's the only way to make sure that you get the best tone out of any wood you choose. I hope you will take a moment to watch the video.