Building a highly responsive guitar: The bridge

The stiffest and heaviest brace on a guitar is the bridge. Changing the mass and/or the design of this important element will have discernible effects on the sound of the strings.

  • A relatively heavy bridge will cause the attack (response) to be slow when compared to a relatively light bridge.
  • A relatively heavy bridge will also reduce the overall volume as it takes more energy to move a heavier object than a light one. Thus a heavier bridge makes for a less responsive guitar.
  • However the law of inertia implies that it will also take longer for the heavier bridge to stop vibrating (An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.) So the heavier bridge augments sustain. How much that matters with the weights involved here is debatable.

Taking all this into account, my approach is to go for maximum attack and volume by using relatively light weight woods for bridges. My target weight is 20 grams for the bridge, not including the saddle. Using a lighter wood like sapele, I can get a bridge as light as 14 grams, which includes a tie block overlay of a denser wood like ebony or gidgee. I also save a few grams by making the saddle from a dense wood like african blackwood or snakewood. The end result, when used in conjunction with properly built composite soundboard with diamond bracing is a very loud and responsive guitar. No one has complained of lacking sustain on these instruments.

Building highly responsive guitars: Bracing

The road to building exceptionally responsive classical guitars is littered with failed attempts and discarded theories. As I experiment a lot I’ve had my fair share of both. But scattered among my failures are diamonds that have pointed the way to designs, materials and processes that consistently result in instruments deemed extraordinary by experienced professionals.

The bracing pattern outlined above is the basis for the most recent, and most highly acclaimed series of guitars I’ve built. I refer to it as the Spyder pattern. I seldom build two identical instruments, but all the Spyder braced guitars have this common conceptual beginning. This design is extremely flexible and seemingly minor variations, like the size of the center diamond, can have very discernible effects on the sound of the instrument. 

When paired with a composite soundboard, and properly constructed, this pattern is a great platform for a highly responsive instrument.

Innovations

The Classical guitar is the challenge that keeps me building instruments after 45 years. As a player I have always loved the responsiveness and lovely sounds that are possible with a well executed instrument. And while the traditional forms are lovely in themselves, many of them succeed in spite of themselves rather than because of them. Throughout the decades I have investigated many aspects of traditional guitar design and experimented with variations that made sense to me. In upcoming posts I will describe some of these variations that have made it into my current offerings.

2017 – Changes to the lineup

During the past few years  I have revamped the line of guitars that I will be offering going forward. The new lineup features:

  1. “Double Top” soundboards are now standard on classicals.
  2. New bracing specifically designed and tested for Double Top construction.
  3. French polish finishes.
  4. 5 piece neck shafts. More stable and less likely to absorb too much vibration.

The move to double top technology is based on the superior performance I get using it. Demonstrably louder, more balanced with greater overhead than my solid top instruments, this is an obvious move ahead of the pack.

New soundboard materials require new bracing strategies, like my split diamond bracing. The results of this flexible fan/lattice/kasha hybrid has produced exceptional results and we’ve just begun to explore the possibilities.

Years working with toxic finishes has left many luthiers physically weakened or dead. The only rational response is to return to the only truly nontoxic finish, shellac, aka French polish. Always the best finish acoustically, it does require more care than synthetics​.