This is not s snide remark so: You could use some rubber, like a piece of rubber band, under the strings near the bridge. You may have to experiment a bit to get just exactly the effect you wish. This approach will not effect the tone or other charastics of the piano but will help to suppress the extra sustain time. If the bridge approach doesn't appeal try some rubber cement directly on the strings to experiment. Rubber cement has the virtue that it is easily removed. Would that all pianos had such a problem. There is no room to install more dampers but I have given this much thought because of a piano that was made without some dampers in the upper area. If need be I will share my so called thinking. Newton nhunt@rci.rutgers.edu
This PTG archive page provided courtesy of Moy Piano Service, LLC