CAUT

Hello,
I'm working on rebuilding a Yamaha C3. I found a scaling discrepancy and I'm interested to hear if anyone else has encountered this on a Yamaha grand or other pianos.

Here is the anomaly. For notes 29-32, which are the 3rd to 6th notes in the tenor, the wire measures at 0.038 - so 16 1/2 American Gauge. This puts it in between gauge 18 and 17 and where I would expect to naturally find 17 1/2. Also, the ink stamps on the bridge from the manufacturer would indicate that as well (except that they are all 1/2 gauge different - a higher number - from American Gauge).

I did measure carefully using different tools to be sure. Two Mitutoyo dial and digital micrometers that are very accurate, and a dial caliper. All of the tools agreed and I have checked and re-checked. That group of strings definitely drops to 0.038" and then the next group up jumps back up to 0.039"

Perhaps we could hypothesize that the manufacturer elected to drop the wire size there to increase string tension closer to breaking-point in order to reduce inharmonicity that can happen with smaller grands in the tenor.

Any thoughts would be appreciated. Many of you are very well-versed in the mathematics and physics at play, and you also have experience dealing with piano scales. You also may have encountered this and made educated decisions on how to respond. I'd like to keep that scale exactly as Yamaha strung it because I suspect that they had a reason and that it was not a stringing mistake. But I'd like to verify the likelihood of that and also not risk string breakage. Using 17 1/2 in that section would be logical and safe - rather than 16 1/2. Also, a compromise could be to use 18 or 17, more so the 17.

Thanks kindly

Totally from memory - but a C3X uses 17 on C#4 on note 41. I know this because I have a warranty case with a loud buzz which may be due to longitudinal waves which cause high and sometimes cause sizzling and phantom partials. 

I replaced the string with a 16-½ but was then told to replace with a 17-½. 

I have yet to return with a second technician to help located the buzz and upsize the string,  but these high-tension scales can have shimmery tonal characteristics and according to Yamaha this is something they do to correct the problem. 

I'm wondering if you're running into a wire changed for this reason. 

Let's us know what you find!

V

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Vincent Chambers

Apollo Piano | Stanford
San Francisco, Chico CA
(530) 924-4469 Mobile; 732-642-1100
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