string calculations threads

[John Delacour]

At 1:12 pm +0200 4/10/06, Ric Brekne wrote:

>...I am getting the sense that while end lengths are extremely 
>important to get consistent during the actual string making process, 
>they are not so important to consider in a scale design program / 
>spreadsheet.

Take for example a single-covered string 1000 mm long of overall 
diameter 3.3mm with copper (rho=8.95) wound on a No.19 steel core 
(rho=7.85)

Suppose we leave 10mm uncovered at the soundboard bridge and 15 at 
the top, totalling 25mm.  The theoretical density of the speaking 
length will be 6.96 g/cc.  If we leave a total of 40mm. uncovered, 
the density will drop to 6.83.  This will produce _theoretical_ 
values of K (see my formulas) of 20345 and	20742 respectively. 
You can calculate what difference this will make in practice.

>One other point.... Hex string.  I would very much appreciate any 
>comments pertinent to how inharmonicity  works out when hex core is 
>used.  I seem to recall that inharmonicity is generally lessened 
>when hex core is used.

Which respectable maker (apart from Grotrian and Ibach 100 years ago) 
has ever used hexagonal cores?

JD