The rim of a grand piano is primarily responsible for maintaining the crown, or curvature, of the soundboard. This curvature is absolutely critical to a piano’s ability to project sound and maintain a tuning to proper pitch. As such, strong, rigid, dense wood makes for solid rim construction. Steinway pianos have a unique one-piece, continuous bent, hard-rock MAPLE rim, Boston pianos have a hard-rock MAPLE inner rim and the outer rim is MAHOGANY. Essex grands have BEECH inner rims and MAPLE outer rims. Many manufacturers do not specify their rim material, possibly obscuring the use of inferior materials or allowing for variations in production.