Alpine Spruce (Swiss Moon) — Picea abies (Moon-harvested)
Compared to all Alpine Spruce (Swiss Moon) samples on the platform
This sample propagates sound waves longitudinally at 4861 m/s. For violin Spruce tops, values exceeding 5000 m/s are exceptional, yielding rapid transients and bright projection typical of fine classical instruments.
Measured density is 433 kg/m³. Premium Spruce tops prefer low density (380-430 kg/m³) to reduce inertia and enhance sensitivity, while Maple backboards prefer higher density (580-640 kg/m³) to act as stable acoustic reflectors.
Young's Modulus is 10.2 GPa. It indicates longitudinal stiffness. Higher stiffness prevents the soundboard from warping under raw string tension, allowing luthiers to shave it thinner for better resonance.
Radiation coefficient is 11.23 m⁴/kg·s. A higher radiation ratio means the wood converts structural mechanical vibrations into audible sound waves in air more efficiently, maximizing volume output.
Acoustic resistance is 2.10 MRayl. Low Z (< 2.2) is preferred for soundboards to allow easy energy transmission from the bridge; high Z (> 2.5) is ideal for backboards to bounce internal wave energy.
These results are calculated from dimensions and weight entered by the user and tap tones recorded with the ToneWood iOS app. The app analyzes resonance peaks using Fast Fourier Transform (FFT). Results depend on the device, environment, support, and tapping technique and are not an independent laboratory certification.