I get a lot of questions from clients who call after an appointment and report that something is wrong with the sustain. It’s often described as follows: “the top octave is sustaining starting at the second F from the top.”

This is normal, and all pianos are designed to do so. The reason the rest of the notes don’t sustain all of the time is due to the dampers, or, the felts that mute the sound when the key is released or when the pedal is returned to rest. Well then, why?

One reason is to allow the notes in the top, which aren’t used as much, to vibrate and ring sympathetically with the notes that are being played below. The sounds from the discant add to the overall voice of the piano, and give it more complexity.

Another reason is because those strings have a much shorter sustain that the longer strings. Play the first A note (not the very last one on the end!) and watch the time it takes for that note to completely stop ringing. On a Boston upright 126E I measured it to be over 40 seconds! Now play the second to last A in the treble, do you notice a difference? That note only rang for around five seconds. So, the dampers stop at around F6 because there really isn’t much use for them up in the top octave.

Included is a photo from an upright piano to show you the dampers and exactly where they stop. The piano is a well used Boston 126, designed by Steinway & Sons.