[CAUT] Sperrhake Harpsichord wire

[Ron Nossaman]

Fred Sturm wrote:

>For a given note (length 
> and pitch), a thicker gauge will be at a higher tension to achieve that 
> same pitch than a thinner one.

Correct.


> The intuitive thing to do when a wire breaks, and when the same size 
> breaks again, is to reach for a thicker, "stronger" wire. And it almost 
> never works (if it does, there was something else happening). Any note 
> on any piano can be strung with #13 wire and it won't break (all right, 
> it has to be a normal piano). Won't sound good, but it won't break. Any 
> wire on a piano can be replaced with a thinner one and it won't break. 
> Think about it. Try it. 

Incorrect. If it does work, it's because the smaller wire has 
a slightly higher tensile strength by virtue of having been 
drawn through a few more dies, which modifies the crystalline 
structure.


> It's a question of thickness, which is really mass in the equations. The 
> extra mass slows down the vibration of the string, meaning higher 
> tension is needed to speed them up. Like with wrapped strings. Add some 
> wrap, and you will slow the vibration rate. To speed it up, you need to 
> raise tension. Same thing with thicker wire, but you don't notice the 
> increase in mass as readily.

The mass of the larger wire requires more tension to reach 
pitch, true, and the smaller wire less tension. The 
misconception inherent here is that tension and break% are the 
same thing. They aren't. The smaller wire will break at a 
lower tension than the larger wire. As a result, the smaller, 
original, and larger wire are all at very nearly the same 
break% at pitch. This is what the math shows, and this is what 
empirical testing has indicated. All these strings will break 
at about the same pitch, on average.
Ron N