---------------------- multipart/alternative attachment Trent Thanks I missed it. I don't read everything. Dale Hi Dale, You probably saw this already, but, just in case, Ron Nossaman touched on one example like you're talking about in a recent post talking about an upright with the break between C3 and C#3, that comes standard with all plain wires on the long bridge. Ron said (emphasis added): "For instance, that 38.75" C#-3 with plain wire trichord will be at about 24% of breaking tension (regardless of wire size, within reason). That's pretty low, and will be very reactive to tension changes resulting from humidity fluctuations, meaning it will go out of tune quicker and farther than unisons farther up-scale, or down scale in the high bass. Tension will be determined by the wire size used there. For instance, unison tension with #20 will be about 404 lbs, or about 369 lbs with #19. Going to a bichord unison, dropping two or three half sizes for the core, and figuring wrap to get back near the unison tension that was originally there will raise the break% to around 40%. That's going to be a more stabile unison with humidity changes, and sound better too. The trouble is, that puts you at the bottom of the list of available copper wrap sizes, requiring about a 0.007" wrap to keep the tension down around where it was with the plain strings. Arledge uses as small as 0.006" for copper wrap. That takes care of C#-3, if the impedance and inharmonicity connects reasonably with the high bass. Now you'll probably want to go 2-4 notes higher with wrapped bichords to blend the impedance and inharmonicity into the rest of the treble. What happens? You maybe need 0.006" wrap for D-3, and smaller than is available for the next one or three. There's the problem, and the reason this doesn't always work that well, and the reason for transition bridges. The speaking lengths are too long at that pitch for wrapped strings. " Maybe that'll help get your discussion going. ( : Regards, Trent ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/8e/17/11/6a/attachment.htm ---------------------- multipart/alternative attachment--
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