calculate the tension if detuned

Discussion in 'Strings [BG]' started by jamersonburton, Sep 27, 2013.

1. jamersonburton

Jul 22, 2011
Can someone calculate the tension of 45-100 d'addario XL nickels (long scale) strings if they were detuned to DGCF (1 full step down).

In E standard:
E- 34.72
A- 40.05
D- 48.35
G- 42.52

Thanks!

2. line6man

At what scale? And why?

3. megafiddle

May 25, 2011
You can look up the detuned tension in the tables at the D'addario website:

That page explains how to use the tables and there's a link near the top of the page

All their strings are listed with tensions for various tunings.

The calculation is relatively simple, though. First find the frequency ratio between the standard tuning tension,
and the detuned tension. The frequency ratio is approx 1.059 for each half step. So for a whole step, the ratio
is 1.059 x 1.059 which equals 1.121

The tension is related to the frequency squared; so square that value to get the tension ratio - 1.121 x 1.121 equals 1.257

Now just divide each standard tension by 1.257

...

4. khutchPraise Harp

Aug 20, 2011
suburban Chicago
Here is what I get. I don't know why my spreadsheet does not return the same results as the D'Addario chart and I don't have time to check it out now but the results should be close.

0.100 E-1 36.24
0.080 A-1 41.70
0.065 D-2 50.94
0.045 G-2 42.50

0.100 D-1 28.76
0.080 G-1 33.10
0.065 C-2 40.44
0.045 F-2 33.72

5. iiipopesSupporting Member

May 4, 2009
If you're taking the original tension figures off the web site instead of the old pdf download; D'Addario has refigured their individual string tension specs.

The mathematical formula, however, is the same. Tension varies as the square of the pitch. So the detuned tension will equal (lower pitch in Hz)^2/(higher pitch in Hz)^2 * current tension.

Jul 30, 2002
Seattle
Owner; Knuckle Guitar Works & Circle K Strings
You'll lose about 9 pounds tension per string.

7. khutchPraise Harp

Aug 20, 2011
suburban Chicago
Yeah, my spreadsheet uses the unit weight numbers from the pdf. If they changed the weights then the numbers will change but of course if they didn't measure them right the first time we can't be sure they are right the second time either....

8. iiipopesSupporting Member

May 4, 2009
They're working on that.

9. ixlramp

Jan 25, 2005
UK
^ What megafiddle said.