I was telling a friend the other day about pianos made with glass soundboards, instead of the usual spruce. (Left: rear view of upright with glass soundboard.) Glass? If it's not wood, it's not a piano, he said. "We might as well just have digital pianos." Then he laughed, "Do I sound like an old fart?"
I'm not sure glass soundboards are the way of the future, but not all change is bad. In fact, the piano has gone through many changes over the years. The piano Mozart used had only five octaves (compared with the more than eight we have today) and no sustain pedals. Even poor Beethoven would only know 6 1/2 octaves on the piano (although he seemed to do okay with those).
As the range increased. the string tension increased. Piano makers also began to use triple stringing (three strings per note or unison in most of the piano), adding to this tension. This resulted in what was known as "cheek disease" -- the caving in of the treble end of the piano. Not to mention problems with tuning stability ...
How would they solve this? Metal braces and iron bars were tried, but it was the introduction of a one-piece cast-iron plate that would do the trick, and that we still use today. There was some grumbling. The plate caused "a decided injury to tone," said Thomas Loud Jr., a Philadelphia piano maker.
What would Tom Jr. say about the glass soundboard?
I watched some videos of people playing these glass soundboard pianos on Youtube, but I think I'd really have to hear it in person to come to any conclusions. It certainly has the benefit of being immune to changes in humidity -- this means it will last longer than wood, and will also allow for greater tuning stability. The maker, STEMCO, also claims it has a warm and more homogenous tone, among other things. What do you think?