Richard, It is possible that the buzz is coming from the soundboard glue joint, but it is not very likely. If you can stop the buzz by applying pressure on the board at the edge, then that would confirm it. If you cannot stop the buzz this way, then look elsewhere. Don't focus on the scrunching or creaking - this doesn't mean there is a buzz. If the board is really loose from the liner, then the board will easily move when you push on it lightly. What else in the piano have you investigated? Is the buzz a high metallic buzz, a low growl, or a woody mid-range buzz? Don Mannino RPT (One who is somewhat familiar with certain Korean pianos)
This PTG archive page provided courtesy of Moy Piano Service, LLC