I'm not sure who said what in this latest exchange. However, whoever it was who said the piano will go flat when the lights come on, is right. The strings of the piano will quickly go slightly flat when the hot light beams hit them, because they warm up rapidly, but the plate does not. The plate is a big heat sink. Three or four hours later, if the piano stays under the lights that long, it will be back up to pitch when the plate warms up. The thermal coefficients of cast iron and steel are similar, but not identical. It will take longer for the lights to dry the board out and the piano to go flat again. Playing against this, you have the fact that wind instruments go about 1.7 cents sharp for every degree F temperature rise, but the orchestra's strings go flat. So the orchestra re-tunes, but the piano just sits there. More often than not, the piano gets rolled out on stage either after the first number, or after the intermission. I don't need to say more. You know what happens. Having said that, I'd still like for everyone in the music industry to agree on a standard (we already have one) and stick to it. This up and down stuff makes no sense. Again, thanks for all your comments. Jim Ellis
This PTG archive page provided courtesy of Moy Piano Service, LLC