Sonically Graded Tonewoods
Superior sound through the science of acoustics.
"At Pacific Rim Tonewoods we offer luthiers the world’s largest collection of sonically graded tonewood."
Soundboards with a difference
Introducing our new collection of Sonically Graded Tonewoods, the first of its kind in the guitar making industry. In this collection, we select Sitka and Lutz spruce that first meets our aesthetic criteria. Using BING technology, we then sonically test and evaluate each soundboard for:
• Stiffness – Modulus of Elasticity (MOE)
• Damping (Q)
Not all the wood we test makes it into our inventory; in fact, over 50% of the wood tested is rejected from our sonic grades. Each piece that does meets our standards is catalogued with its unique sonic properties. This enables luthiers to specify a similar sonic profile reliably and repeatably.
Making the Grade
Sonic grading is fundamentally different from traditional grading; the process relies entirely on data and mathematical models. To have reliable models, you need data – lots of it. Through thousands of BING tests and multiple research studies we have amassed enough data to define ideal ranges of density, stiffness, and damping (Q) for a soundboard. Our sonic grades are based on three major criteria:
Density: Only boards with a density between 350 kg/m2 and 500 kg/m2 are accepted.
Stiffness(MOE): Stiffness is immensely important to the performance of a soundboard, yet it proves the difficult to model. In general, as the density of a soundboard increases, so does its stiffness. Each test we perform evaluates stiffness at the given density of that unique board. To meet the sonic grade, the measured stiffness must fall within +/- 10% of the average stiffness.
Damping(Q): Most important, the measured value of damping(Q) must be above average. This eliminates half of all the wood we test. If the value of Q is under 150, it is rejected from our sonic grades.
The soundboards that make it through all the above criteria are then further divided into three major density ranges (all units in kg/m3):
350 <= low <= 400
400 < Medium <= 435
435 < High <= 500
The result of this testing and grading is a soundboard that truly stands above the rest, having made it through a process that rejects over 50% of all tested samples. Each sonically graded soundboard comes with its own data sheet specific to that piece.
Shown is a sample of 1700 sonically tested boards, of which more than 50% have been rejected from our sonic grades. Note the consistency of the blue data points.
Luthiers on Sound
In his book, Contemporary Acoustic Guitar Design and Build, Trevor Gore, a renowned luthier based in Australia, provides a logical and scientific method for designing guitars, and gives real answers to questions that have challenged luthiers for centuries.
Miroslav Tadic, musician, composer and luthier, plays a Trevor Gore guitar crafted with a Pacific Rim Tonewoods Sitka spruce sonically graded soundboard.