7th string as the "chanterelle"

Discussion in 'Sevenstring Guitars' started by droic, Sep 10, 2021.

  1. InfinityCollision

    InfinityCollision SS.org Regular

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    D'Addario NYXL strings hold up well at A4 on standard scales, and are much easier to source than O4P. I use a single NYXL as my A4 string, with standard strings for the rest. Barring that or a shorter (<610mm) treble scale, I would echo the suggestion to tune down to G#4 or G4. That was my approach for several years before the NYXL strings were available.
     
  2. ixlramp

    ixlramp SS.org Regular

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    A quick comment on gauge ...

    For a plain steel string: As you vary gauge, tensile strength varies identically to tension. Both are proportional to gauge squared.
    What this means is that, theoretically, the breakability of the string (due to tensile strength withstanding tension) is independent of gauge, so you can use whatever gauge you prefer for A4.

    Of course, additional real-world factors will probably make a difference. A thinner string might be more prone to breaking due to being damaged by imperfect hardware. So this makes me think a .008 might be less fragile than a .007.
    I have noticed that Octave 4 Plus seems to have shifted towards larger gauges for A4 compared to a few years ago, like .008 or even .009, maybe the above is why.
    Of course, the larger gauges will be high tension, but the extra mass will help the volume of the string.

    Anyway, i also suggest not being trapped by standard tuning (which is bad anyway). Consider tuning 1-2 semitones lower.
     
  3. LostTheTone

    LostTheTone Elegant Djentleman

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    The reality is that available string gauges simply aren't made to tune that high. After checking the calculator, A4 on a 007 string on a 25.5 neck results in 15lbs of tension. That's not all that different from a 009 string tuned to E4. But the 007 string cannot take anything like the same amount of stress before it snaps.

    The thing is that stress is force over cross sectional area. The difference in diameter between 007 and 009 is 2 thou, but area comes from R squared. The area of a 007 string is something like 975 square microns. The area of a 009 string is 1600 square microns, like 70% greater area. If you run the numbers back through, the stress on the 007 string at 15.6lbs is 71MPa, where the stress on a 009 string at the same tension is 43MPa.

    And this is why everyone is saying you need a seriously short scale, because that kind of stress is simply not reliable. If you tune down to G#4, you already cut that strain down to 63MPa, and if you tune down to G4, that becomes 56MPa. Yes, that's still higher than the 009 tuned to E, but at least there is some scope for you actually pick the string without snapping it.
     
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  4. ixlramp

    ixlramp SS.org Regular

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    That can easily be misinterpreted, sorry, i do not mean 'standard tuning is bad' =)
    I mean: In my opinion, it is bad to trap yourself in standard tuning.

    The A4 subject has been discussed a lot on this forum, lots of information here https://www.sevenstring.org/threads/the-a4-and-beyond-thread.162586/

    In agreement with the previous post, A4 on 25.5" is simply on or just over the borderline of practicality due to the tensile strength of typical string steel, whatever gauge you use. So you either need special materials (Octave 4 Plus or D'Addario NYXL) or a shorter scale.
     
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  5. Captain Shoggoth

    Captain Shoggoth literally just vibing

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    Thanks for this explanation! What calculation tools could a layperson use to test out the MPa of different scale length /string gauge configurations?
     
  6. InfinityCollision

    InfinityCollision SS.org Regular

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    Manufacturers tend not to divulge their exact specs on strings - composition is a trade secret, maybe the alloy was developed in house, blah blah blah blah blah. A228 steel (piano wire) is a good choice for estimating limits on common plain strings. I don't believe good info is available for NYXL or the like. I laid out some formulae on this subject in the A4 and Beyond thread years ago, around the time Ernie Ball's M-Steel strings were announced. The short version of the ensuing math is about what you'd expect from collective experience: A4 is just barely possible at standard scales, but you're pushing to the very edge of yield strength on standard strings so results in practice may vary (usually unfavorably).

    I also gave some guesstimates for practical M-Steel tuning limits/scale lengths given marketing data. D'Addario's information on NYXLs is very limited, but arrives at a similar conclusion: both strings should be able to handle slightly beyond A#4 at standard scales, so A4 is entirely practical and even allows for small bends. This also aligns with my experiences using NYXL strings for A4 on two 25.5"/650mm guitars.

    There are several important considerations to remember here: any values given are within a defined tolerance, account for yield strength (when permanent/"plastic" deformation occurs, not just when it outright breaks according to tensile strength), and remember that small faults and rough points along the string's length (bridge/tuner burrs, breakpoints, etc) are likely points of failure that may reduce your practical window further.

    Wrapped strings are a whole other can of worms, but also aren't much of a concern here so we get to dodge that problem.
     
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  7. LostTheTone

    LostTheTone Elegant Djentleman

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    There is not a simple tool, unfortunately.

    I used the venerable String Tension calculator to get the tension calcs, and that's where you can set the scale lengths too. String gauges are the diameter of the string in "thous" (thousandths of an inch) so take that, divide by two, then do Pi R Squared to get the area, in "square thous". There is a formula to convert thous to microns (thousandths of a millimeter) which I can't remember, but if you stick it into google that will sort you out.

    Once you have the tension in pounds (or kilos, pour les francophones) and the area in microns then you can use this calculator and just punch in those numbers and it'll spit out the Pascals or PSI.

    In principle strumming and fretting add strain in a linear fashion, which is not related to thickness and that is broadly the problem here. I have no idea how much strain it actually adds to deform a string by picking it or bending it on the fretboard, but that extra strain is (more or less) the same no matter how thick the string. That same calculator can take you through Young's Modulus and all that if you want to get into it in depth.

    Even without knowing that exactly; you can start to get a sanity check just looking at the broad numbers. Thinner strings are less strong, but need to survive the same amount of strain. A 009 at E is fairly robust, but we've all broken them. A 007 at A is physically weaker, and is inherently under more strain at the same tension, and then your fingers add the same amount of extra force on top of that.
     
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  8. bostjan

    bostjan MicroMetal Contributor

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    If yield strength were the issue, I'd expect the string to detune during normal use. I don't believe that is generally the observed case, though.

    I know I've brought this up more than once before, but consider the pedal steel guitar. Scale lengths are variable from one pedal steel to another, but they are generally very near regular guitar scale lengths (24"-26", typically), and standard E9 tuning includes a G#4 with a pedal that bends up to A4. That's the way it's been for 60-ish years. The people who make those instruments know the value of having a wider bend radii around the nut and saddle, so as not to break the string.

    I've been playing around with high A strings since the 1990's, and I was able to achieve a useable, musical-sounding string on a fairly cheap guitar without using any special strings. It might be worth noting that I had some trouble repeating my success on my nicer guitars. In retrospect, I now think that the bridge design had something to do with it. Steve Vai originally wanted the UV to have a high A4, but Ibanez told him it was impossible, yet Fender, around the same time, successfully developed one with the high A with a 25.5" scale length (but notably, it went through multiple bridge iterations).

    Why do you think this is?
     
  9. Robstonin

    Robstonin SS.org Regular

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    OP: I had an Epi SG tuned to CGDAea (low to hi) with a 60 for the low C and NYXL 007 for the high a. Never broke the high a even though I didn't go easy on the bends. The 24.75 scale length definitely helped so what about a 7 string Heafy LP to test drive your chanterelle idea IRL, or one of the older 7 string PRS SEs with the 25" scale?
     
  10. olejason

    olejason SS.org Regular

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    I'm surprised no one has built a tunneled high A string. Kinda like the flipped version of a banjo.

    [​IMG]
     
  11. bostjan

    bostjan MicroMetal Contributor

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    Then the tuner would be in the way of your fretting hand, no?

    Plus, why?
     
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  12. LostTheTone

    LostTheTone Elegant Djentleman

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    I am no expert on steel guitars, but you play them with a slide don't you? Which I suspect explains why there is more leeway with them tuning up higher. You don't need to deform the string anything like as much to get the note you want.

    Notably, pedal steel guitar bridges aren't shockingly different to a guitar bridge. But they do seem to favor rollers or cylindrical contact points over saddles. And I think you're right that this does make a difference. In an absolute sense, I don't think we're talking about pure breaking strain on strings. It's much more about where force can get focused. When you have a nice, polished smooth surface like a slide or steel bridge piece there the force gets distributed evenly and so the string is ok.

    I think that if you took a les paul, put on a bridge with roller saddles, and then played it with a slide, I think that would work just fine. You might even be able to tune up higher. But if you want to play it like a guitar, and particularly if you want some whammy bar, then you are going to have real problems.

    A 007 string at A is under the same tension as a 009 at E. It's not some super light floaty thing. You still have to positively fret it, and you still need some effort to bend it.

    I agree that an optimal bridge/nut/tuner combo would result in elastic deformation before a clean snap, but I think on a real world guitar the margins of the 007 will just be too small to observe it. You might see that happen as you tuned up, perhaps. Maybe if you just very gently pulled the whammy bar you could get it to stretch first. But I think that in practical playing situations where you want to work in whole semi-tones, then you would just go for a note and take it past the point where it will snap.

    I think the "one tuner someplace else" idea has some merit though. You could, in principle, have a separate little micro-bridge for the high string that was a couple of inches further up the guitar body. Either make it a headless style thing, so you tune the extra string at the bridge, or have a normal tuning machine up top. Either way you get a shorter scale length without having to go with a more extreme multi-scale affair.

    Of course, you'd then have to reposition pickups or only have one pickup, and I guess it's up to the player whether they would rather have a fanned fret that goes down to 23" or whatever else. Personally I don't want a top A string anyway, but from an engineering perspective I think this is at least viable.
     
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  13. bostjan

    bostjan MicroMetal Contributor

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    Basically. The "slide" is solid, though (not that it makes any difference). However, there is significant change in tension applied to the string by the pedals. A standard E9 tuned steel guitar has three pedals, two of which are used very consistently (pretty much like you'd use your gas and brake pedals driving through heavy traffic). One of those two pedals bends the high G#4 up to A4.

    Having played steel guitar for a couple years on a mostly daily basis, I can say that the high G# was the string that broke 99% of the time. I only recall one instance of it breaking during a gig, though, and I'd usually get at least a couple weeks out of it. My main steel guitar is 24" scale, but my backup is 25.5".

    Have you ever seen those Manson custom guitars from the 80's/90's? This was before fanned frets really were known, and the luthier made these designs where the strings were different scale lengths, but as a step function, rather than as a slant. I'd need to look at photos again, but I want to say some or most were headless. I think that'd be the way to go with a design like that. With a banjo, though, when chording up high, the thumb string is tuned the same as the highest normal string, so it's fine, but you get a re-entrant tuning for strumming. If the string was on the treble side of the fretboard, I'm not sure what the point would be, unless it was tuned to a short interval fretted, which could be cool but take a while to get used to.

    But it might also be a guitar that would be very difficult to resell if you stopped digging it.
     
  14. olejason

    olejason SS.org Regular

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    No, the string is tunneled through the neck and the tuner is still on the headstock. The purpose is that you can have a high A (or whatever) string in a more playable gauge and tension. Functionally, you're moving the nut for the chanterelle further up the neck.

    The downside is you have a bulge where the chanterelle terminates but it can be fairly seamless. Chording would also run the risk of feeling a little strange. It would be a very niche instrument for sure, definitely not something for the masses.
     
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  15. bostjan

    bostjan MicroMetal Contributor

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    Ahh, I see. I thought I was looking at some unique 6 string banjo, but that makes more sense.

    One could achieve the same concept by simply clamping the high string down at the desired fret.
     
  16. jwade

    jwade Doooooooooom

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    Can you post a picture/clip of that Samick? I was completely unaware of them making one! My Samick SG is by far the best playing guitar I’ve ever owned, genuinely stomps every Gibson SG I’ve ever played.
     
  17. bostjan

    bostjan MicroMetal Contributor

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    I don't have a picture handy, but it's the same model and colour as this one: https://reverb.com/item/5690765-sam...sign-pickups-in-transparent-green-korean-made

    I don't really recommend too highly, though. Everything on my Samick 7 was installed kind of misaligned. I think I only gave something like $120 for mine, new.
     
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  18. ixlramp

    ixlramp SS.org Regular

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    Perhaps you know this, perhaps i misunderstand you =) but ...
    This might achieve a more robust open A4, but 'on the frets' the highest string will actually be less than a fourth above the adjacent string, so this would essentually be the same as having a smaller interval between the top 2 strings.

    Thought i would mention some tricks for the top string that Oakland Axe Factory used when building Garry Goodman's most recent 12 string (single course) ERG (29" scale with an A4 string):
    * Headstock break angle minimised.
    * Tuner as close to nut as possible (so conventional inline headstocks are the least suitable).
    * The top string is actually clamped to the saddle block to eliminate the section from saddle to string anchor (actually similar to the concept i have been promoting elsewhere).

    It seems that the lengths of string beyond nut or saddle increase the chance of breakage for extreme high strings, as does more extreme break angles.
     
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  19. jwade

    jwade Doooooooooom

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    Pretty cool look though. Kind of has an Ernie Ball vibe. I really like the black saddles on chrome baseplate.
     
  20. MaxOfMetal

    MaxOfMetal Likes trem wankery. Super Moderator

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    Manson out of the UK gave that a try on some of their headless designs in the 90's.

    E9B2061D-8D38-46EF-B079-1C4A063CD168.jpeg

    Sorry for the shitty quality, a lot of Hugh's work has proved the old adage "that once something is on the internet it can't be deleted" wrong.
     
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