string tension

[FunkMetalBass]

Good ol' physics to the rescue again.

However, John's point is sort-of leaning in the right direction. Since the core of a string is more dense than the wraps, (theres no empty space in the core), upping the gauge by increasing the thickness of the core will increase the tension more than increasing the thickness of the wraps, because it adds more unit weight.

I don't think that's true unless the core is actually more dense than the wraps, and given the array of string-building materials, one can't make that blanket statement.

I'll do the geometry for it all and get back to you.

 

[fourfinger]

Short answer: Chromes.

Long answer:

Don't use D'Addario's string tension chart universally. It is not intended to apply to all brands.

D'Addario Chromes are among the higher-tension flatwound strings -- I have them on and I think they sound great, and don't play bad for the high tension they offer.

I have switched back and forth between Chromes and TI Jazz flats (similar gauge but have lower tension) -- it definitely affects action, and if the bass was set up right before, it requires a small truss rod adjustment.

 

[dj150888]

I don't think that's true unless the core is actually more dense than the wraps, and given the array of string-building materials, one can't make that blanket statement.

I'll do the geometry for it all and get back to you.

I was talking about in an "all other things equal" scenario. For example, a solid string with no wraps would be more dense than a string of the same gauge with wraps, solely because of the circular profile of the wrap necessitating empty space in there - thats going to reduce the overall density of the string taken as a whole. The larger the core, the less empty space that would be taken up by space around the wraps.

Edit - visual example of what I mean

Its the empty space between wraps that I'm talking about. Circle packing efficiency in that profile is terrible, so the less space taken up by the circular part of the profile vs the linear part of the profile, the less empty space, and so, the higher the density.

 

[FunkMetalBass]

I was talking about in an "all other things equal" scenario. For example, a solid string with no wraps would be more dense than a string of the same gauge with wraps, solely because of the circular profile of the wrap necessitating empty space in there - thats going to reduce the overall density of the string taken as a whole. The larger the core, the less empty space that would be taken up by space around the wraps.

I know what you're saying, and I still think that it only applies in the case of round core strings.

So let's do a thought experiment for hex cores!

String 1: core of radius* 1.5mm, wraps of radius 1.5mm = 9mm total outer diameter
String 2: core of radius* 2.5mm, wraps of radius 1mm = 9mm total outer diameter

Treating the outer wraps as tori, and examining a 6mm length of string,
String 1 has a total volume of V = (6)(A_core) + 2(V_wrap) = 8.769 + 266.463 = 275.232 mm^3.
String 2 has a total volume of V = (6)(A_core) + 3(V_wrap) = 24.357 + 207.052 = 231.409 mm^3

So, assuming uniform density of all materials (and assuming I did my math correctly), the string with the thinner core will actually have a greater unit weight and greater actual tension than the same gauge string with a larger core. However, the string with a larger core will feel more stiff.


*circumscribed circle's radius

 

[johnk_10]

Take a look at the pdf

Tension is determined by open note pitch, scale length, and the unit mass of the string. For a string on a particular scale, tuned to a particular pitch, it is unit mass that determines tension. Unit mass (also called unit weight) is the mass of 1 inch of string. Wrap layers add to the unit mass to a string, therefore increasing tension.

i read that years ago. are you going by what you read or by experience?

here's a good and simple to understand example for you.

take a stratocaster. put on a wound D string that is a .026 gauge, and feel the tension of it. most of them have a core gauge of .014 now remove it, and put an unwound .026 (solid) string on it. it will have ALOT more tension. it's the core and not the wrap that dictates most of the tension.

the first DR bass strings (1989) had smaller cores than most of the other conventional strings but they had a thicker wrap. this is what made them more slinky (less tension) than other brands of the same gauge.

 

[dj150888]

i read that years ago. are you going by what you read or by experience?

here's a good and simple to understand example for you.

take a stratocaster. put on a wound D string that is a .026 gauge, and feel the tension of it. most of them have a core gauge of .014 now remove it, and put an unwound .026 (solid) string on it. it will have ALOT more tension. it's the core and not the wrap that dictates most of the tension.

the first DR bass strings (1989) had smaller cores than most of the other conventional strings but they had a thicker wrap. this is what made them more slinky (less tension) than other brands of the same gauge.

In the case of round-cored strings, the maths I was discussing explains why a thicker core will have MORE effect, but increasing the gauge by just increasing the the wrap gauge will have a more-than-negligible effect. I can't remember the precise packing density for a circular profile like that which would be on a guitar string, but off the top of my head, I think its 78.5%. That means that on a circular core string, increasing the gauge by increasing the thickness of the wrap will increase the tension by (in simplified maths, approximately) 78.5% of the tension increase by increasing the core alone. Its a large difference, but not nearly as large as your posts imply.

Going by a lot of your posts, you seem to have some sort of problem accepting that your observations can be explained by physics and psychology. I take the opposite stance.

What your post doesn't address is hex-core strings. Funkmetalbass has provided some maths that suggest that in hex-core strings, the opposite is true. I'll check over the figures when I get a chance and get back, but it seems sound to me on a quick scan.

Funkmetalbass, you correctly noted that my point was only relevant to round core strings, my apologies for not taking hex-cores into account!

 

[ixlramp]

However, John's point is sort-of leaning in the right direction. Since the core of a string is more dense than the wraps, (theres no empty space in the core), upping the gauge by increasing the thickness of the core will increase the tension more than increasing the thickness of the wraps, because it adds more unit weight.

Yes that's true.

However with gauge constant at for example .100, a huge change in core size, for example .020 to .025, will replace .005 of wraps-with-gaps with .005 of solid core, which results in a only tiny increase in mass. So I get the feeling the result of increasing core size is a very very slight increase in tension. Also, the core size is very restrained, as not to cause stiffness, so the leeway for increasing core size is small.

The effect would be bigger for thin roundwounds, such as .025, and of course a plain .022 is significantly tighter than a wound .022.

 

[ixlramp]

So, assuming uniform density of all materials (and assuming I did my math correctly), the string with the thinner core will actually have a greater unit weight and greater actual tension than the same gauge string with a larger core.

Hmm ... it seems obvious to me that the larger core string will have more mass and more tension. EDIT: AH! of course, the hex core itself has gaps in it's structure!

take a stratocaster. put on a wound D string that is a .026 gauge, and feel the tension of it. most of them have a core gauge of .014 now remove it, and put an unwound .026 (solid) string on it. it will have ALOT more tension.

Yes i totally agree with that. But for larger strings the effect is small, and far outweighed by the effect of adding wraps. Adding wraps to a string adds mass, and by string physics, that increases the tension, that's the laws of nature.

 

[johnk_10]

IME, it's not just about the overall mass. if you have a thin core with a heavy wrap, verses the same gauge with a thicker core with a thinner wrap, the thinner core string will have less tension.

i remember rotosound making multi-cores (IMO, they were horrible strings). they felt slinky, but when you tried to bend them, the rolled under your finger instead of sliding across the fret.

 

[dj150888]

Yes that's true.

However with gauge constant at for example .100, a huge change in core size, for example .020 to .025, will replace .005 of wraps-with-gaps with .005 of solid core, which results in a only tiny increase in mass. So I get the feeling the result of increasing core size is a very very slight increase in tension. Also, the core size is very restrained, as not to cause stiffness, so the leeway for increasing core size is small.

The effect would be bigger for thin roundwounds, such as .025, and of course a plain .022 is significantly tighter than a wound .022.

A change of .005 on a string of .100 gauge is going to be less significant than a change of .005 on a .040 string of course, but the relative difference in how much tension is increased by upping core radius vs wrap radius stays the same.

To use an example, using my simplified figures from before, if changing the gauge from a .040 to a .045 by increasing the wrap radius, the tension increase will be 78.5% of what the tension would've increased by if upping the core radius. Likewise, when upping from a .100 to a .105, increasing the wrap alone will still yield a tension increase of 78.5% of the increase that would be obtained by upping just the core radius. On large strings, a larger increase is needed to have a comparable increase in tension, but the relative difference between increasing core vs increasing wrap doesn't change. While it mightn't seem like a huge difference, 21.5% is significant enough for me to want to take it into account.

Disclaimer - this discourse refers to round core strings only!

 

[dj150888]

IME, it's not just about the overall mass. if you have a thin core with a heavy wrap, verses the same gauge with a thicker core with a thinner wrap, the thinner core string will have less tension.

But thats because of the overall mass. In the example you mentioned, the string with the thinner core will have less tension because it has less mass, even though they're the same gauge.

 

[ixlramp]

that's why as set of true flat wounds (flat ribbon) generally have more tension that roundwounds, even if their outer diameter is the same gauge as their roundwound counterpart.

Flat wrap has no gaps in it's structure, so the string is denser, has more mass for the same gauge, and therefore more tension.

 

[johnk_10]

i don't not believe it's just about the mass.

take a string's wrap (say an .010") without a core on it and pull on it. it will just uncoil with practically no resistance. now take a straight wire the same gauge as the wrap and pull on it. it will have quite a bit of tension.

IME, small cored heavy strings can flop around due to their mass/weight, but heavy cored thinly wrapped strings are very stiff.

 

[ixlramp]

take a string's wrap (say an .010") without a core on it and pull on it. it will just uncoil with practically no resistance. now take a straight wire the same gauge as the wrap and pull on it. it will have quite a bit of tension.

Yes, the wrap wire is under zero tension. Some people then assume it therefore doesn't affect tension. But it does so indirectly, by adding to the mass of the string. A heavier string needs more tension applied to it's core to get it up to pitch.

I go by the laws of nature and string physics.

I'm very interested in the possibility that with hex core, a larger core reduces the mass, I may have to do the maths on this ...



KNUCKLE_HEAD!!!

 

[dj150888]

i don't not believe it's just about the mass.

take a string's wrap (say an .010") without a core on it and pull on it. it will just uncoil with practically no resistance. now take a straight wire the same gauge as the wrap and pull on it. it will have quite a bit of tension.

IME, small cored heavy strings can flop around due to their mass/weight, but heavy cored thinly wrapped strings are very stiff.

So what is it about then? You seem to be missing the substance of my posts entirely. Yes, the thick cored string will have more tension (in the case of roundwounds or wrapped versus unwrapped at least), but that can be accounted for by the mass of the string.

Pitch, scale length and unit mass. You can attribute any change in tension to one of those things.

 

[knuckle_head]

Part of the reason a hex core has more mass by measure than round core is that hex core is measured on the flat surface of the hexagon - there is 18% more mass in an identically gauge hex core than round core.

FWIW there is a way to wind a .100 to have more mass than a .105 so formula is not moot.

A stiff string may not be in your interest - it arrests harmonics, and a thick core will do the same thing.

 

[dj150888]

FWIW there is a way to wind a .100 to have more mass than a .105 so formula is not moot.

I was hoping you'd chime in!

Could you elaborate on this point a little?

 

[ixlramp]

take a stratocaster. put on a wound D string that is a .026 gauge, and feel the tension of it. most of them have a core gauge of .014 now remove it, and put an unwound .026 (solid) string on it. it will have ALOT more tension. it's the core and not the wrap that dictates most of the tension.

Looking at the unit weight values for a plain .026 and a wound .026 on the D'Addario pdf, the plain has a much higher unit weight, this is what creates the higher tension. I'm agreeing with you that a larger core may well increase tension, but it will do so by increasing the unit weight. Everything is taken into account in the unit weight.

The physics published by D'Addario are correct and match academic sources, I even derived the string equation myself at school

 

[knuckle_head]

I was hoping you'd chime in!

Could you elaborate on this point a little?

The more wraps you have the more latitude you've got, and in general no manufacturer wants to use a wrap finer than .006 because it takes too much machine time and material, but if you consider the gaps - yes, mind the gaps - the finer the wire used the more solid it is as a layer.

There are things you cannot force a wound string to be by formula as you end up with warbles that make a string look ugly - though they will function just fine.

Too much more and each of you will be my competition . . .

 

[dj150888]

The more wraps you have the more latitude you've got, and in general no manufacturer wants to use a wrap finer than .006 because it takes too much machine time and material, but if you consider the gaps - yes, mind the gaps - the finer the wire used the more solid it is as a layer.

There are things you cannot force a wound string to be by formula as you end up with warbles that make a string look ugly - though they will function just fine.

Too much more and each of you will be my competition . . .

So its a case of approaching as close as possible to a solid wire using as fine a wrap as is still structurally and aesthetically stable?

You can count me out as competition at least, string manufacture and design is too much physics and engineering for me, I'm a simple chemist! Too much maths and not enough explosions for my liking in your field!