One of my regular clients, a local pharmacist who is an accomplished pianist, called me yesterday. His 1936 Bluthner grand was about due for tuning, but he was concerned about extraneous noises he could hear when playng certain notes. He played a few over the phone but I couldn't hear what he meant. So I went along today (he lives very near me) to find out what was what. I couldn't at first hear what he was referring to, then I got it. A very high-pitched ringing, or buzzing, a "feather" on the edge of the decay of the wave envelope. In addition, in the treble, a "tapping" sound with quite a few notes. I think both phenomena may be down to the same cause, which I'll come to in a moment. I checked the bridge pins on the most "offending" notes. Solid. Seated the strings across the bridge with my thumb. Tuned the unisons carefully. Not much difference. Checked hammer fit to strings - even. Hammers need refacing mind you, and because he is a good pianist and uses the una corda pedal, the hammer have six grooves, not three. Refaced the "worst offender". Not much difference. So: Examination of the soundboard shows two hairline cracks, one quite long and visible because the edges seem discoloured, which makes me think it may be an old fissure, the other VERY hairline, and shorter. I listened from above and below the soundboard while he played individual notes and some Rachmaninov. Listening to the problem sounds, they were clearly worse in the Rachmaninov than in the single notes. So: I conclude that the problem is the soundboard cracks and worse when complex Rachmaninov being played, as larger and more complex movements required of the soundboard. The tapping sound in the treble, I felt might be due to loose hammer flange screws, and so it proved. So at least I was able to get rid of that particular annoyance! Now, why has the customer only noticed this "feather on the sound" phenomenon over the last week or two? (He's had the piano about 5 years). My theory for what it's worth, is this: We are currently having the longest sustained cold snap in this area for years. Other parts of the Britain are getting many inches of snow, but right here, it snowed a couples of weeks ago, and has frozen ever since. I believe what may have happened is that ambient humidity may have gone down considerably (there is no frost on the car in the mornings now, as no moisture in the air to condense and freeze). I suggested to the customer that lower ambient humidity could have aggravated the effect of the soundboard fissures. In addition, it might have affected the hammer flange screws. As an experiement, I have suggested that he put a wet towel on a stool under the soundboard, just to see what happens. In the meantime, I would appreciate advice about what might be done with the soundboard? The very narrow splits are not nearly wide enough to shim. What, if anything, might be done? The customer took some pics while I was there and emailed them to me, and I am attaching a couple. Many thanks, David Boyce. -------------- next part -------------- A non-text attachment was scrubbed... Name: Bluthner1a.jpg Type: image/jpeg Size: 24425 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100106/db4c1672/attachment-0002.jpg> -------------- next part -------------- A non-text attachment was scrubbed... Name: Bluthner4a.jpg Type: image/jpeg Size: 30267 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100106/db4c1672/attachment-0003.jpg>
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