I had that"D buzz" myself....same note(s)... it turned out to be comming from slighly loose bolts on the piano truck, where the legs sit. Get down under there and bang that sucker with a closed fist right in the middle. :-\ In the small hall here , the overhead lights or curtain tracking also likes to buzz to that pitch. Moving the piano makes it go away. On the other D I found the hinge pin buzzes mentioned as well. Sometimes the locks on some pianos will buzz but not every day. I have called the dealer out on occasion, when the piano teachers complain. But neither of us was able to locate it, because, ofcourse it would not buzz when we were there. I think it was the teacher's portable metronome. Anyhow...I have also found that the prop stick on some pianos is a very good source for this, acts kind of like the soundboard peg in violins. Grab one sometime and see how much vibration is going through it! good luck, Richard
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