音響的にグレーディング - 保管庫

In the regular Sonically Graded collection, tops are sorted into broad density categories—Low, Medium, or High. You get low density, and the range of Q only goes so high. Additionally, each set includes a sticker on the top with all the data. 

The Vault, however, offers greater control. You can filter by specific density, MOE, or Q values, matching what you’ve used before or dialing in a target tone. Vault tops also include the highest Q values in our inventory, not available in the standard sonic sort. 

For luthiers looking for tonal consistency or trying to replicate the response of a previous build, the Vault offers a unique opportunity: the ability to select a precise set based on real sonic data, not just a general grade.

Sonic grading has been a game-changer for our suppliers. While luthiers relied on instinct, touch, and ear to separate ordinary wood from true tonewood, sonic grading helps guide your choices better. It’s not as if it replaces the tap altogether, but it gives you more consistent data to work with. We use the BING method developed in France. A small steel ball is dropped on the board, and sensors record its natural vibration. The data is analyzed to determine three key parameters — density, stiffness (MOE), and damping (Q). Together, they predict how that soundboard will perform acoustically. The process is entirely non-destructive, so each board arrives exactly as tested.

It depends on your playing style, tonal goals, and the size of the guitar you're building.

• Low density (350–400 kg/m³): Highly responsive and warm. Ideal for fingerstyle players or light-touch techniques. Best suited for smaller-body guitars where delicacy and nuance matter most.
• Medium density (400–435 kg/m³): Balanced across the tonal spectrum with good projection and warmth. A versatile option for mid-size guitars and mixed playing styles.
• High density (435–500 kg/m³): Offers strong projection, clarity, and dynamic range. Well-suited for jumbo or large-body guitars, or for players with a heavier attack who want more headroom and focus.

Each category is clearly labeled so you can match tonal goals to measurable wood properties.

Currently, we offer Sitka spruce and Lutz spruce, both selected for their stiffness-to-weight ratios and tonal reliability. Every board is first visually vetted for grain and color, then sonically tested. As research continues, we may expand to other species in future collections.

Not visually, no. The sonic tops you see in the Vault collection are not the actual tops. But the sonic data is real. Each listing in the Vault represents a set with actual measured values. You can filter by your preferred specs (density, stiffness, Q value), and once you find a match, you’re purchasing that specific set with those exact properties.

All Vault sets are dried, stabilized, and conditioned in our dehumidification kiln. Moisture content is kept at 8.5% +/-range for long-term stability and tonal reliability. We store them in a climate-controlled environment. That being said, we always recommend that you dry and acclimate the wood according to your own schedule/protocols.

Tap-testing remains valuable, but sonic grading adds objective precision. The BING system quantifies what the ear senses; from stiffness and resonance to sustain, giving luthiers confidence that each top meets specific acoustic standards. It doesn’t replace intuition; it complements it with data that’s measurable, repeatable, and comparable across builds.

New pieces are added about 1–4 times a year, sometimes sooner, depending on what comes through the mill. Because each set is truly unique, availability is limited, and pieces often sell quickly. To get early access to pieces added, you can sign up for our Luthiers’ Edge Vault Newsletter.