# FWIW: String Set Tension, D'Ad 9s vs. 10s

Discussion in 'Tech-Talk' started by PCollen, Sep 21, 2021.

1. ### PCollenSenior StratmasterSilver Member

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Just re-arranging my supply shelf. Got some sets of D'Ad EXL110s and EXL120s . On the back of the packs it states the total string tension of the installed set: EXL110 (10s) = 102.52 lbs, EXL120 (9s) = 84.44 lbs.

The above tension is calculated on a 25.5 inch scale length fretboard (such as a Fender Strat or Tele) and tuned to standard pitch (EADGBE).

On the D'Addario web-site there is a much more detailed string tension chart with formulas for making calculations .

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2. ### FuncleMansonStrat-Talker

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I'm kinda nerdy, so I find this interesting. Thanks!

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3. ### ThreeChordWonderSenior Stratmaster

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f = (1/2.L).sqrt(T/u)

f = mode 0 natural frequency ( half sin wave)
L = string length
T = tension
u = string weight per unit length

So it follows that in order to achieve the same frequency f, if the string gauge and therefore weight per unit length goes up, then the tension must too.

4. ### Thrup'ny BitGrand Master Curmudgeon

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And the EXL130s I use are lower tension still.

5. ### ToneRangerMost Honored Senior Member

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I'm so nerdy on this that I have an Excel spreadsheet tension calculator.
I tried the D'Addario balanced tension strings, and the lower strings feel a little floppy, so I'm currently using what I would call a "progressive" tension set that increases evenly in tension as you go from high E to low E.
Standard 9's are the worst though - the swing in tension from string to string is almost silly - there is nearly a 4lb difference in tension between the B and G alone.
Standard 10's aren't perfect, but much closer to being balanced for a stock set.

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6. ### LOSTVENTURESenior Stratmaster

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If you do any shopping at "JustStrings" you'll see that in their product description they break down the tension per string.

7. ### kurherStrat-O-Master

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If you want to calculate the tension, the formula supplied by @ThreeChordWonder is the one to use (provided you know the unit weight).

Keep in mind that tension calculators are only valid for the products of the manufacturer that supplied them because the unit weight is rarely identical from brand to brand.

Having said all that, tension is not the only important consideration. Ideally the tension between the strings in a set should be close but there are many other important variables like the tension to stiffness ratio and geometry/winding method on wound strings, not to mention materials.
Then again guitars can vary so much that experimentation is probably the best way to find what works best for you.

8. ### PCollenSenior StratmasterSilver Member

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What do the periods in the formula denote .. multiplication ? If so, is the value within the first para calculated as 1/2L or L/2 ?

Last edited: Sep 21, 2021
9. ### ThreeChordWonderSenior Stratmaster

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One divided by two times the scale length.

[1/(2 × L)] x sqrt(T/u)

The 0th (zeroth) mode which corresponds to 0th natural frequency- the one you tune to - is a half sin wave so the full wavelength is 2 x the scale length.

Physics huh?