An evening appointment with a friend in Bed-Stuy - a mysterious buzzing sound caused by firm blows on D# and E5 above middle C appeared in the last few weeks. I knew that some part of the piano was vibrating sympathetically with this general part of the sonic spectrum...I guessed that the culprit was a crack in the Sound board based on the sound, as well as the suddenness of the symptom's appearance - the Sound board is highly susceptible to swelling and shrinking in response to the environment's relative humidity, and this piano had two factors working against it - close proximity to a baseboard heater and an outside window. When the Sound board wood changes volume by sucking up or releasing moisture, it can bring the inside faces of a crack into just the right distance from each other for them to vibrate against each other in response to certain frequencies, causing an annoying buzz.
The D# unison had slipped out of tune more than the adjacent notes - equalizing the three strings to the proper tension prevented this note from exciting the buzz - I concluded that the note had moved out of tune towards the frequencies that vibrated this as yet undiscovered crack, and returning it to it's proper place ameliorated the condition. The E was still in tune, and caused intense buzzing. I didn't see any obvious cracks looking down through the strings from the top, so I had H. play the note repeatedly while I explored the underside of this Steinway baby grand - I soon found that pressing up on the second to last sound board rib stopped the buzz completely, and noticed an obvious crack.
The proper repair for this condition was beyond my capabilities and the customers' budget - we worked a small amount of Cyanoacrylic super glue into the crack, known for its ability to "creep" or seep deeply into small spaces, even without the aid of gravity, hoping this would stop the crack from vibrating against itself in the same way. This helped the situation somewhat, although it was very difficult to accomplish this upside down and we were getting more glue on our fingers than desirable. We stopped for the night, satisfied that we'd diagnosed the buzz, and H. plans to find a better way to work glue into the crack to perhaps completely solve the condition. Of course, it may go away again on its own as the humidity continues to change.
Since H. is a friend and it was an unusual late night appointment, we celebrated with a Heineken on the fire escape while listening to a record he prizes - a recording of Fritz Reiner (Who H. praised for his "militaristic precision - he was a complete asshole, but he got results.") conducting the Chicago Symphony in Ravel's "Spanish Rhapsody", "Pavane for a Dead Princess" as well as Rachmaninoff's "Isle of the Dead."
Thanks for an enjoyable evening's work H. and your tips on my playing on the Beethoven Sonata - I look forward to your report that the buzz is gone.