Round vs. hex core string stiffness

[David Jayne]

About the neck movement: it may be a red herring. It's possible that since these Lo-Riders feel 'stiffer,' I reduced the relief to get the action down so it felt better(yes, I know this is procedurally incorrect, bear with me). I DID sight the neck after putting the strings on and playing it a bit....it seemed awfully difficult to play immediately after putting them on.....when I sighted the neck I THOUGHT I saw more relief than usual so I took some out........but I never measured anything so......maybe I'll measure the action, swap the Sunbeams back on and measure again. That's what I should have done.

 

[KJung]

I'm still concerned about the neck movement, though. There's something strange there.

Just to be clear, I assume you mean you are concerned about neck movement only as an input to answering the question about tension differences. In the 'real world', who cares, since that is what the truss rod is for. Often, a neck will need adjustment when changing brands or models of strings of the same gauge. There is no 'problem' there at all.

It is an interesting but kind of meaningless issue for me. The hex core DR's definitely 'feel' tighter than the round cores. Why they feel that way is an interesting question from a science perspective, but doesn't really matter to the player. Adjust the neck up and be happy with either one. They do feel and sound different. Again, if you want a more aggressive stainless steel tone versus your Sunbeams, but want to keep that 'round core' buttery, slinky, rubbery feel, the DR Hi Beams or Fat Beams (a bit deeper sounding and not quite as zingy) would be the thing. If you dig a more rough upper mid grindy response and a tighter feel, the Low Rider steels are great.

 

[David Jayne]

The hex core DR's definitely 'feel' tighter than the round cores. Why they feel that way is an interesting question from a science perspective, ......

And that's why we're here, Ken. That's the only reason. Curiosity, that's all.

 

[96tbird]

Nowhere near science, just speculation. My dim, dusty mind pictures this: Hex cores lock the winding's in place, that's why you don't run as much risk on the winding's unwinding when you cut them; round cores don't lock the wraps, you need to bend before cutting or..... Even then; I killed a Black Beauty G, even though I bent it. It held up for a week and then just died. When I took it off, it laid out in an "S" shape instead of being straight.

I think that round cores feel "noodlier" because: as the string deflects, the wraps spread apart on the outside and compress on the inside of the wave, like a slinky. Because the wraps are round and not kept from moving on the round core, they don't impede movement. As they spread out on the top of the wave, they can roll a bit on the core, like bearings, unlike the locked wraps of hex core. The mechanical resistance on the wraps on a hex core (the wraps can't roll on the core) impedes the amplitude of the wave. Less travel for the same fretting or plucking force.

Braced for the flaming.

 

[Creese]

I think that round cores feel "noodlier" because: as the string deflects, the wraps spread apart on the outside and compress on the inside of the wave, like a slinky. Because the wraps are round and not kept from moving on the round core, they don't impede movement. As they spread out on the top of the wave, they can roll a bit on the core, like bearings, unlike the locked wraps of hex core. The mechanical resistance on the wraps on a hex core (the wraps can't roll on the core) impedes the amplitude of the wave. Less travel for the same fretting or plucking force.

I was thinking the same thing in addition to the inherent physical properties of a hex vs. round cross section. Like a laminate mat'l has different properties than the individual parts, so would a string. In effect creating a structural member.

But more importantly, I like "noodlier".

 

[KJung]

And that's why we're here, Ken. That's the only reason. Curiosity, that's all.

+1 Cool thread!

 

[David Jayne]

Regarding actual 'stiffness,' or resistance to bending, I did this little test, several times, several different ways. These are the same .105 E's from my other tests. If one string was more flexible than the other, I'd expect to see it here, and I'm getting no real result. If anything, this time it looked like the Lo-Rider was slightly more flexible than the Sunbeam.

 

[96tbird]

Aha, but that has one flaw, since they are the same gauge, it stands to reason that the hexcore has less mass than the round, no?

 

[David Jayne]

Possibly. See post #19. But the difference is so small I can't see it having an impact.

 

[ixlramp]

Interesting. Maybe that's what I remember Skip saying with regards to his strings - not that the hex cores are larger, but that he uses specific winding techniques to give his hex cores more mass.

Hey FMB, it just occurred to me what may be the cause of the confusion.
Perhaps knuckle_head was saying that, since the gauge of a hex core is measured from flat side to flat side not point to point, if you have 2 cores of equal gauge, one hex and one round, the hex core will have more mass. This is where your diagram is correct, the circle sits inside the hex.

However with 2 strings, one hex core, one round core but with identical outer gauge and identical wraps, the round core will have more mass since it completely fills the space inside the inner wrap, whereas the hex core just touches the inner wrap at it's corners, leaving gaps in the structure. In this case the hex sits inside the circle.

EDIT: I dimly remember the thread, perhaps KH said something like 'for the same gauge, hex core has more mass than round core' and was referring to the gauges and masses of the cores, not of a complete string.

 

[96tbird]

ixlramp, that's what I was getting at. There's space under the wraps = less mass.

Edit, I just grabbed a pack each of Sunbeams and Lo-riders, both 45's. The package says the E cores are .022 on both. This indicates to me that the gauge of the hex is measured on the points; at least in DR's eyes. It would have to be that way or it would double the inventory of wrap wire they need to have on hand. The wrap wires are the same guage on both sets. Now I understand that Lo-riders are stainless, but they make hex core nickel lo-riders too.

 

[jasper383]

Nowhere near science, just speculation. My dim, dusty mind pictures this: Hex cores lock the winding's in place, that's why you don't run as much risk on the winding's unwinding when you cut them; round cores don't lock the wraps, you need to bend before cutting or..... Even then; I killed a Black Beauty G, even though I bent it. It held up for a week and then just died. When I took it off, it laid out in an "S" shape instead of being straight.

I think that round cores feel "noodlier" because: as the string deflects, the wraps spread apart on the outside and compress on the inside of the wave, like a slinky. Because the wraps are round and not kept from moving on the round core, they don't impede movement. As they spread out on the top of the wave, they can roll a bit on the core, like bearings, unlike the locked wraps of hex core. The mechanical resistance on the wraps on a hex core (the wraps can't roll on the core) impedes the amplitude of the wave. Less travel for the same fretting or plucking force.

Braced for the flaming.

I think this is right on the money.

There are, in my observing strings, two things at work in how a string "feels": the tension, and the side-to-side stiffness.

Round core strings, all other things constant, will have more of that side-to-side flex that translates into the string feeling slinkier.

This is why flats feel like they have so much more tension, even if a set has the same tension as a comparable set of rounds. Flats don't have nearly as much side-to-side give.

 

[Lee H]

I can tell you, though, that I've taken a caliper to strings and found that they can vary by as much as +/-.0025" from what the manufacturers claim they the gauges are.

I would not find this unreasonable. You are dealing with a material that is subject to significant expansion and contraction with temperature. The likelihood of you finding the exact same temperature of the manufacturing facility, on the day the strings were made is not all that probable. I have seen machine shop variances based on time of day, do to the heaters being on a timed cycle.
Even measuring tools can be off with temperature. That is why micrometers come with a standard to reset them to zero

 

[David Jayne]

This is why flats feel like they have so much more tension, even if a set has the same tension as a comparable set of rounds. Flats don't have nearly as much side-to-side give.

I don't agree with this 'stiffness' theory at all. Take a look at post #47. There is virtually NO difference in bending resistance. And the amount of bend shown is much, much greater than you will ever create while actually playing the strings.

 

[Eublet]

I haven't read all this, but there's more to this than pure tension. Different shapes also have different flexibility characteristics. In the end, the round core strings allow a manufacturer to get a certain mass in a specific diameter which isn't possible with hex cores. There really isn't much one needs to understand here. Just find a string with the tension, flexibility and tone you like.

 

[Eublet]

Regarding actual 'stiffness,' or resistance to bending, I did this little test, several times, several different ways. These are the same .105 E's from my other tests. If one string was more flexible than the other, I'd expect to see it here, and I'm getting no real result. If anything, this time it looked like the Lo-Rider was slightly more flexible than the Sunbeam.

Your test doesn't take into consideration many other things though. There are just a lot of factors to be considered here. If one wants to understand them all just for fun, then that's cool. I just don't think it's necessary if you just want to find a string you like.

 

[David Jayne]

If one wants to understand them all just for fun, then that's cool.

That's the only point of the thread. Curiosity.

 

[ixlramp]

I just grabbed a pack each of Sunbeams and Lo-riders, both 45's. The package says the E cores are .022 on both. This indicates to me that the gauge of the hex is measured on the points; at least in DR's eyes.

I can understand that measuring point to point would simplify the design of string formulas since this is the diameter the inner wrap sits on.

 

[FunkMetalBass]

Aha, but that has one flaw, since they are the same gauge, it stands to reason that the hexcore has less mass than the round, no?

If it is the case that the hex core has a smaller cross-sectional area than the round core, it stands to reason that it is likely more flexible as well (again, I haven't figured out how to determine the sectional modulus of a hexagon, so I can only speculate). However, the hex string has less mass, so there is less gravitational force pulling it down.

The differences in mass and core cross-sectional area are so minute that they would appear to be the same from the naked eye anyway. In fact, I bet the difference with more precise measurements is still trivial.

This is why flats feel like they have so much more tension, even if a set has the same tension as a comparable set of rounds. Flats don't have nearly as much side-to-side give.

There's a lot going on with flats that makes them feel stiffer. Consider this profile view of a string (cut lengthwise):

For one, they use flat wraps instead of round wraps, so there is appreciably more mass on a flatwound string with the same gauge as the round (in fact, ~1.27 times as much mass per wrap if we consider one-wrap strings). Secondly, because all of that open space isn't there, the the wraps have less ability to move and roll, decreasing flexibility.

I can understand that measuring point to point would simplify the design of string formulas since this is the diameter the inner wrap sits on.

I agree with that claim also. Although in order for the outer wrap to "grip" the hex core, it would undergo mild compression at each point. I suspect the point-to-point measurement of the hex cores is slightly larger than the diameter of the round core.

 

[Mulebagger]

I have absolutely no scientific knowledge to back this up, but I thought the round core would oscillate more freely based on it's shape versus the hexcore. I didn't think it was related to mass because I've played hex cores that were lighter gauge than some round cores and they still felt stiffer.

The round cores like (DR) that are my personal favorite, feel like they twist or roll more freely under my fingers and give the feeling of being more rubbery.

I hope a string person can help out with the debate.