Steinway Model D

The Model D is the largest piano Steinway makes: just under nine feet long, a little over five wide, and close to half a tonne, its rim bent from long laminations of hardwood and its cast-iron plate holding a string tension of more than twenty tonnes. Most buyers are concert halls and conservatories, because the instrument is too large for most homes, and on American stages, by one estimate, more than nine in ten concerts played on a concert grand are played on a D.

Its design was settled in the 1880s by the founder's sons. Henry Steinway Jr. worked out the action and string scale, C. F. Theodore Steinway the iron frame, hammers and laminated rim, and Albert Steinway the pedal mechanism. The firm's concert grand had won at the Philadelphia Centennial Exposition of 1876 and was renamed the D in 1878. After a prototype was tried in concert in 1883, the company unveiled a new D in 1884, with a longer bass section, a redesigned plate and a bent rim, the instrument it has made ever since.

What has changed since is small. In 1936 a soundboard tapered from its thick centre to a thinner edge was introduced, and the action has since been adjusted to need less force at the key. An experiment with Teflon bushings in the New York action, begun in 1961, caused clicking and stiffness and was abandoned in 1982. The very first D of 1884, identified from the firm's delivery ledgers, was bought back and put into Steinway's concert rental stock as CD-001.

The D is built in two factories, in Queens and in Hamburg, and pianists distinguish their sound, the New York instruments often described as mellower and the Hamburg ones as brighter. The company has passed from the Steinway family to CBS and through several owners since. Of roughly 600,000 pianos it had built by 2010, about 25,000 were Ds.