> > The piano came back "dead". Very limited sustain - less than 5 seconds in > octaves 6 and 7 (many notes). Extremely dead rear duplex - less than 2 > seconds in top two sections. Weak upper partial volume and sustain > throughout. Bass is tubby. False beats throughout; weird out-of-tune partials > in the bass. All these tonal phenomena occur whether the string is struck by > a hammer, or is plucked. > > After racking my brains about this piano (I service it about 2x per year), I > finally had the idea to measure the height of the bridge cap above the > soundboard, on both the speaking length side, and on the rear duplex side. > The rear duplex side is anywhere from 2/32" to 6/32" inch _higher_ than the > speaking length side. Tom, Is this the original, or had it been recapped with the restringing? A negative front bearing will kill sustain and make noises you can't tune out, but won't affect the back duplex. What's the bearing front, rear, and overall? Is there any crown in the soundboard - all areas? > > Does this sound like a rolled bridge? How is a rolled bridge caused? Is there > an accurate way to diagnose a rolled bridge? Can it be fixed in the field? No, it sounds like a dead soundboard and a bad bridge capping. Bridges don't roll. They are supported by soundboards, and follow wherever the soundboard goes. If a bridge "rolls", it's because the soundboard has failed. Bridge roll isn't a cause, it's an effect. Check the bearing (front, rear, and overall) and crown (bass, tenor, treble as far as you can reach, not just at the long rib). >From your description, I'm guessing you will find no, or negative crown in the killer octave, and negative front bearing in places. It likely needs a board and bridges. Ron N
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