lydplanke

Lydplanke, or soundboard, is the thin, curved wooden plate that forms the primary vibrating surface of many stringed instruments. The name comes from the Norwegian words lyd meaning sound and planke meaning plank or board. The soundboard translates the vibrations of the strings into audible sound by transferring energy to the surrounding air and to the instrument’s body, shaping overall volume and tonal color.

Construction and materials: In most classical guitars and pianos, spruce is used for the top (the lydplanke) because of its lightness and stiffness. Other woods such as cedar or maple may be used in different instruments. The soundboard is typically braced on the inside with a pattern (fan bracing on classical guitars, X-bracing on many steel-string guitars) that determines stiffness and resonance. Its thickness varies across the plate to balance strength and vibrational response.

Function and role: The soundboard is driven by the strings through the bridge and saddle. Its bending and vibration set up air vibrations that radiate outward, while coupling with the instrument’s body reinforces and colors the sound. The geometry of the plate and its bracing, as well as humidity and temperature, influence sustain, brightness, and projection.

Variations by instrument: In violins, violas, and cellos the top plate serves the same function as the lydplanke; in pianos the large soundboard beneath the strings is central to sound production and projection. The term is used primarily in Nordic languages; in English, “soundboard” is the common term.

Maintenance: Soundboards are sensitive to moisture changes and can crack or deform if exposed to rapid humidity shifts. Proper climate control, careful handling, and occasional professional maintenance help preserve tonal quality and structural integrity.