Hi, 1. Strings contacting bridge pins/notches 2. Damper stop rail too high? Lim <blockquote type="cite">On 10-Mar-2012 10:34 AM, "Tom Driscoll" <<a href="mailto:tomtuner@verizon.net">tomtuner@verizon.net</a>> wrote: John, A few things come to mind . First is to do what you have done already. Look , listen, tighten , touch . On thing that can help is whilst the pianist is activating the buzz get your head right over the board . First put one ear down toward the board wherever it seems the loudest then quickly turn the other ear down. Essentially crawl all over and under the piano doing this. I'm not sure why but for me the stereo effect of doing this can lead me toward a location. Finding where it's coming from is a good start toward a solution. If I think it's a case part I remove the lid and listen then remove each other part with a test each time.Top stick, stretcher, even the music desk holders inside the rim. Sometimes the problem follows the case part. Also remove the lock from the stretcher if the stretcher can't be removed. I'll bet we all have goofy stories about this type of problem so here is mine. A long time client with a fairly new Bosendorfer calls about a buzzy awful noise . We both do just as you did with your client. No luck and I was getting frustrated so I stepped back while she played. Problem solved ! It was an old rusty metal bathroom medicine cabinet on the floor 12' from the piano waiting to go out to the curb on trash day. We had both heard the noise IN the piano. Good luck, Tom Driscoll ----- Original Message ----- From: "Rebecca and John Silva" <<a href="mailto:misc@rjsilva.com" target="_blank">misc@rjsilva.com</a>> To: <<a href="mailto:pianotech@ptg.org" target="_blank">pianotech@ptg.org</a>> Sent: Friday, March 09, 2012 6:59 PM Subject: [pianotech] What's causing this vibration? Hi, When playing a particular note on a piano I saw today (Baldwin L) a harsh vibration would so... John= </blockquote>