A couple more elusive groans I have encounter: 1. On some korean grands, the lid prop hinge is mounted on the music desk guide block. To support the weight of the lid, they have installed under the guide block, below the hinge, a bolt that can be turned down till it contacts the plate. There is a lock nut on this bolt to hold it in place once it has been adjusted. If that bolt loosens up it can cause such a groan. 2. I found some excess glue drippings under the bass bridge between the shelf and sound board on a baldwin once. It was a last ditch effort, but I took a piece of sound board steel (from apsco catalogue) ran it under the bass bridge shelf and all that loose glue came out. It eliminated a very elusive buzz that plagued me for three tunings. good luck, John Gunderson, Neptune City, NJ harvey wrote: > BB, > > No opinions on the signal Ginny, except it seems a lot of effort for what > could be disappointing results. Here are a few elusive grunts I found, in > no particular order -- 'cept for the first one from last week: > > - decorative concrete cat on carpet, adjacent to rear leg with brass > ferrule. Strangely, F4 was the frequency that caused the cat and the leg to > get together; > > - keyframe bedded, but one keyframe glide was waffling side-to-side in the > keyframe due to hole being drilled oversized (frequency dependent); > > - bulkhead mounted sostenuto rail mounting bracket loose (freq & velocity); > > - "dancing" washer under loose plate lag (freq/velocity); > > - loose leg mounting plate; the part on the piano, not the leg (Kawai-style > mount, although it wasn't a Kawai); > > - microscopic gap between plate and nose bolt "shelf" (Paul Monroe found > this one, and it may have been more of a buzz or sizzle than a grunt) > > I'm sure there are more, equally elusive, but at the moment, they're > eluding my memory too! FWIW, I now have an F4, velocity dependent grunt on > a Yamaha CFIII. The typical/easy/reachable stuff has been checked, but nine > feet is a lot of area to cover from the keyboard, even with my trombonist's > arms. I too need to somehow excite the piano while doing a walk-about. > Funny, there's never an extra hand when you need 'em. Good luck! > > Jim Harvey, RPT > > At 10:45 PM 7/11/99 -0400, you wrote: > >I'd been listening to a grunting sound, like a fallboard-to-front-stretcher > >or loose metal lyre brace, during the tuning of a Falcone 74, sympathetic > >to F4. In trying to chase it down, the best I could come up with was that > >it was coming from inside the action cavity (loud and clear). > [cut]
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