In a piano a panel, which takes the place of the usual cast iron string plate or frame, is provided for supporting the strings. The panel is a sandwich construction making it exceptionally strong and capable of withstanding the string loads without bending or otherwise yielding and without requiring auxiliary support such as the massive wooden backs or trusses to which cast iron string plates are usually attached. The string panel has a relatively thick low modulus of elasticity core layer, a portion of which is made of laminated hard wood to serve as a pin block, and relatively thin layers of high modulus of elasticity material, such as steel, bonded to the core layer. If desired the string panel may be used as the main frame of the piano to which other major components, such as the soundboard, key bed, side cheeks, housing and feet, are directly attached.