henry copeland: We're hearing a thud, the echo of last century's piano boom: pllqt.it/t4eKN6So from 1900 to 1930, the golden age of piano making, American factories churned out millions of them. Nearly 365,000 were sold at the peak, in 1910, according to the National Piano Manufacturers Association. (In 2011, 41,000 were sold, along with 120,000 digital pianos and 1.1 million keyboards, according to Music Trades magazine.) The average life span rarely exceeds 80 years, piano technicians say. That’s a lot of pianos now reaching the end of the line.