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What kinds of things can be done to affect the string tension during guitar setup? Assuming a guitar already has light tension strings, is there anything else that can be done? The only thing I can think of is lowering the saddle, however the action is good so I don't want to do that. I've read reviews of other guitars where they mention the guitar has been setup to play with light tension. Am I missing something obvious here?

Thanks!

John

John, I understand the question some what but I am not sure of what you issue is. What problem are having in regard to string tensionMichaelP38706.6722569444

[QUOTE=John Elshaw] Am I missing something obvious here?[/QUOTE]

Nope. For a given scale length, the only way to adjust tension is to change string gauges, or the type of strings (nylon; silk-and-steel). Raising or lowering the action just makes it feel more or less stiff, respectively; it doesn't affect the tension of the strings.

I guess that should have been my question. The information I was reading said the guitar was setup for minimal tension and string stiffness, (eluding to easy playability), and I was just wondering what could possibly have been done other than picking strings with less tension or lowering saddle height.

Doesn't a higher saddle have lower tension? For example, scale length is determined from nut to saddle, but as saddle height is increased, so is the scale length (although very little, but still increased), right?

John

I really like the string tension on a PRS. What is the reason they are easier to bend etc. Aren't their fret scales like Gibson's? What is teh secret.

I have an old LP Special 3/4 - now I understand that great slinky action due to the smaller scale - but PRS??

Dennis

Isn't a PRS a 25" scale?

A PRS scale length is 25" while a Gibson is 24 3/4 a Fender is 25 1/2. Ever notice how a Fender fights back when you play it while a Gibson is a bit mushier. That is the scale length playing its part. As for the tension adjustment a try a minor change in the truss rod to acheive very different "feels" in tension. It is remarkable when I show a customer the difference between a straight neck and one with a bit of relief in it. Give the truss rod a turn in either direction and feel the difference. Some people perceive there to be more tension when the neck is straight , other people think there is more tension when there is relief in it. I like a straight neck but in my book the customer is always right.Hope this helps,
        Evan

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http://www.NewYorkGuitarRepair.com

[QUOTE=John Elshaw] but as saddle height is increased, so is the scale length (although very little, but still increased), right?
[/QUOTE]

Yeah, I guess in practice that would be true when you fret a string; but I think it would have to be really high to have it behave as an appreciable increase in scale length. The actual pounds of tension exerted by the open strings, though, would be unaffected by saddle height.

John,
   Raising or lowering the saddle height doesn't affect the scale length at all. A 25.4" scale is still a 25.4" scale no matter how high or low the saddle is. As long as the string is stretched to pitch between two points at a predetermined length, the scale is locked in, What changes is the angle at which the string breaks over the saddle and the overall length of the actual string including the ends beyond the nut and beyond the saddle.

   Another factor or dimension that affects that overall length is the angle of intersection between the neck plain and the headstock amd tuner placement. Those break angles are what you're experiencing tension changes through when you change sadde height.

   Some builders like a string plain that rides fairly high over the top of the guiyar and then enters the bridge behind a sharp break angle over a good amount of saddle height. These tend to exhibit slightly hgher tension than a set up that presents and lower strng plain and a lesser angle over the saddle to the bridge pin or anchor points.

   Both set ups can provide the very same dimensional results as far as string height off of the actual fingerboard surface and fret crowns while offering completely different heights for that plain off of the body itself. Tension is the very reason that we builders settle on our default dimensions and set up parameters for angles at both ends of the string in both scale and overall length beyond the scale length determined by nut and saddle placement.

   25 and a half is alwasy 25 and a half, but tension can vary widely from guitar to guitar depending on the combination of these dimensions and angles.

   The selection and use of a heavier or lighter guage string set is the very simplest way to vary tension after the guitar's string plain dimensions are selected and commited to by the builder/designer of the instrument.

   I just finished a full size J(Jumbo) model for a customer who travelled from Washington DC to pick it up. He prefers a true medium guage set of phosphur bronze strings for their obvious ability to deliver the volume and projection due to the additional mass compared to that of a light guage string set. I adjusted the head angle slightly and coordinated the neck approach angle for the neck set and the bridge height to allow the set up provide a final tension that was very deceivingly loose and light feeling. The playability was much like that of the same guitar with light guage strings and a standard neck/bridge/saddle height dimension configuration. Scslr length is stil my default 25.5", but I've had great succes in achieving various string tensions on different guitars over the years. On my first three hundred or so acoustic guitars, I used a set headstock angle and approach set up, but began to experiment and prototype instruments with variations at both ends of the string plain to document the differences and have adopted a set of those variations to achieve results in both directions. I guess it's alot more of a complicated issue than many luthiers want o tread or explore, but it is a fact that I've been able to apply readily and practically to this day and I'll break the 500 guitar mark in the coming year.

   As I played for the very first few chords I was immediately happy with the final results since i prefer a light guage set on my personal guitars. He asked if it had the mediums on it when he first played it since it had a very loose lower tension feel with nice low action. He and hid friend who was with him played and tepped and bent for about an hour before they headed out and made several comments about the comfortable tension feel that the guitar offered even with the medium strings.

   Just some thoughts that come from nothing more than my experience and experiments or the years and hundreds of acoustic guitars and thousands of set ups and repairs.

Regards,
Kevin Gallagher/Omega GuitarsKevin Gallagher38707.6897916667

Greg,

Thanks, that's great info. It's starting to make more sense now. I have a question regarding your setup you described. It sounds like you built the neck/saddle angles to lower tension, but your customer used medium strings because he liked the volume. Will lowering the tension through setup decrease the volume since the strings are no longer transfering energy to the soundboard as effectively with lower tension vs. higher tension? Does the setup not make enough difference to affect volume differences from different types of strings?

Thanks!

John

The scale length really does not change, as it was previously said. The fingerboard is fretted and bridge placed for whatever scale length you cut them at and then are fixed. If you move the saddle or the nut one way or the other (up or down), you will change the length of the string, but not the scale length you built the guitar for (after it is properly set up, that is). Sorry if this has already been said.
However, moving the saddle or nut height up or down as much as 1mm on a 24.5" scale would only net a difference of .0000315" (Robbie, this is WAYYYYY smaller than a skoshe).
I would challenge any human being to be able to tell the difference on that string length. The difference would be felt in the way the action played but not the string length.
The relationship between one particular string, the note it is tuned to, and the scale length is fixed. Changing one of these variables will change your tension or your note.
As far as a personal playing preference, you may try tuning down a 1/2 or whole step and capo'ing up a fret or 2. That would loosen up your action and keep your notes where you need 'em.
-j.

_________________
“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

The pitch of a string is determined by three things: mass, length, and
tension. The break angle is not going to change the length and mass of
the string, and hence it's tension at a given pitch will not change either.
The tension of the string between nut and saddle at a given pitch cannot
be affected by break angles. But that isn't the end of the story.

What some people experience as a difference in string tension when
break angle changes at the bridge may be a change in the flexibility of
the top as the string is plucked. If the top is torqued more with a higher
saddle, it has less room to flex with the tension increase from plucking,
and the string is experienced as more tense.

Another factor that may be experienced by the player as a difference in
string tension is a difference in the length of string between the nut and
tuners, and between saddle and tailpiece (the differences in the length of
string between saddle and pin with a pin bridge as the saddle height
varies are pretty negligible) IF the string can move freely across the nut
or saddle, the stretch of the extra string beyond the nut or saddle can
make the string feel like it is at lower tension. This is especially
noticeable on bent notes. I suspect that the reason higher break angles
at the nut are experienced as higher tension is that the string does not
move freely across the nut so the stretch of the upper part of the string is
not a factor in the feel.

I also think a sensitive player can feel the difference between a stiff and a
flexible neck when plucking the note, other things being equal.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard,
   Howard I agree with much of what you said, but have experienced tension differences from guitar to guitar with their break angles varying, but scale lengthe being identical and hav built so many with those variations being applied intentionally that it is a given for me and is very obvious from one to another.

When you said that ptich is determined and affected by mass, length and tension, I have to disagree with the mass and length since pitch is generated solely by tension. Whether a string is long or short, heavy or light, it can be pulled to a particular note or pitch as long as the stucture supporting it can endure the tension and stesses created as a result of it.

   You can easily take a low "E" string measuring a whopping .070" in diameter and pull it to concert pitch at a true "E" note. On the other hand, you can just as easily thake a string intended for use and an "A" string measuring a much thinner .042" in diameter and pull it to that same true "E" note or pitch over the same scale length.

   The length is the same, the mass is signifigantly diifferent, but the tension that each is exposed to generates the note that is heard when they are activated. Tension creates the note. Mass and length are applied through the science and calculation needed to achieve consistent tension and consistent feel for the player asthe strings are pulled tight enough to offer the six notes in the open guitar register. A perfect exampl of that calculation system being applied is the grand piano.

   Mass at the tension necessary to generate a desired not will have a huge bearing on the comfort level for the guitarist and length of a string stretched to a desired note will also have a noted affect on the comfort since it obviously takes much less tension to generate a note on a shorter scale than it does to generate the same note on a longer scale.

   Many players who use drop tunings or alternate tunings as a standard for themselves use a heavier "E" string at the bottom to maintain that even tension while dropping the note.

Kevin Gallagher/Omega Guitars

Man, this is getting way too complicated! I think Howard is right on the money in his description of what's happening. It's the COMBINATION of mass, length and tension that creates any given pitch. The pounds of pull created by any string is the result of its mass being stretched between two anchor points to a desired frequency of pitch--i.e., a bigger (more massive) string equals more tension at any pitch. You can't change that with any kind of setup. If you change the tension, you change the pitch. It can't be any different. As Howard wrote, the feel, or stiffness, of a string can be affected by a number of factors, but the pounds of tension created by a string at pitch must remain constant, or the pitch will change. Some seem to be confusing "tension" with "stiffness." They're not the same.

As for John's statement about a higher saddle equaling an increase in scale length, I think he meant that it would create a functional, rather than an actual, scale increase. At least that's what I meant in my response. If, for instance, you had a 3/4" tall saddle, and didn't change the normal angle of your neck, the effort to fret a string at the end of the board would stretch it far enough to have the EFFECT of of a longer scale, because you will have increased the string length considerably. The scale and tension of the open string, however, would be unchanged. Any saddle height used on a playable instrument, as J. Brown mentioned, would have no appreciable affect on scale length.

Carlton,

    My point was simply that mass and length do not generate pitch, but only determine the tension necessary to do so. It's solely the tension that any string of any mass or length has applied to it that determines its pitch or note. It's a pretty clear fact. A string of .046" tuned to an "A" will present the same note as a string of .052" tuned to an "A" at the same scale length. It's the same note being generated by the two very different strings, but because of the difference in their respective masses, the tension varies greatly to porvide the desired note with each.

   It's really pretty simple and is applied every time we select a guage of strings to give us the tension we desire while tuning to the very same notes with each guage available. A lighter string tuned to concert pitch offers less tension or resistence for the player as he frets and bends the strings and a heavier string offers higher tension or resistence since it takes more "tension" to bring to concert pitch. The length is the same but the "tension" has to change due to the mass difference between them. It's pretty clear that the actual mass has nothing to do with the pitch of any string, but the tension that is needed to create the desired pitch will have to increase or decrease according to the mass of the strings.

   The same needs to be considered for the length of the string course. A long or short string can be drawn to a desired not, but the tension needed to attain that note will also have to increase or decrease according to the length present. In either case, its the tension that must vary to accommodate the changes in either of the other parameters.

   Not very complicated. I guess I'm just simplifying it since it's what I've done all day every day for the past twenty two years or so.

   Sorry for the confusion.

Kevin Gallagher/Omega GuitarsKevin Gallagher38707.6956134259

Something else to keep in mind is that not all strings of the same external gauge are equal internally, ie the core that the wind is wrapped on. This will cause different manufacturers strings to have different tensions for the same gauge at the same pitch.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Wow, that solidifies my thoughts on why my slinky Yamaha plays so well. The bridge is shaved low (I like playing close to the body)

Also it is a shorter scale. I can't figure why more fingerstyle guitars aren't using shorter scale. (I suspect I'll verify my suspicions shortly...IE altered tunings, articulation)

I think my most recent guitar sounds a little tight. It has a Cocobolo bridge and Engleman top. GC body style. The bridge is 11/32", and Coco may be a little more mass.

My thought was to shave the bridge down a little, adjust the heel a bit. (I still haven't glued the tongue down)

Thoughts? Kevin - I'll be bringing this, and maybe a couple other guitars with me for you to look at when I visitTerry Stowell38707.8173263889

Kevin,

It looks like we're in basic agreement here. My point, in regard to the original question here of setup affecting tension, is just that it takes an interaction of mass, length and tension to reach a desired pitch, and that any setup can not change the pounds of tension on a string without affecting its pitch. As you and Howard have said, in different ways, a setup can affect the perceived ease or difficulty of playing a guitar. The tension of the strings at a given scale length, though, can only be changed by using a different gauge or type of string.

After all the discussion here, I decided to pull the saddle off my Martin OM21 and tune it up a little. First question: what are Martin saddles made of? It definitly isn't any type of bone because it didn't smell in the least when I sanded it down. I took it down a little too low, but I'm not worried because I'm gonna replace it with a real bone saddle anyhow. There were two huge differnces, both of which were expected. First, playability was really increased by less stiffness in the strings, and closer action. It didn't seem to affect intonation at all. Second, there was a HUGE drop in volume of the guitar. I never noticed it much before on classicals because of the low tension nylon strings, but it was really prominant with the steel strings. Time to go start shaping a bone saddle.

Cheers!

John

CarltonM,
Agreed. There are multiple phenomenons that occur as the slightest change is made to any of a number of dimensions, angles and parameters in guitar setup and structure. The physics of string tension and its applicationto a guitar's top, bracng and neck are comlexed and confusing alo tof times and it is nearly impossible to lock in any set deductions since the materials are organic and completely unique from guitar to guitar.

   I guess that's ne of the things that keeps it new and interesting for luthiers and repair people.

   

Terry,
most builders who have focused some of their efforts on guitars specific to the fingerstyle and alternate tuning genre have adopted a longer scale length to accommodate the drop tunings. As the tunings are lowered, the longer scale can compensate for the more slack rotataion of the strings as they vibrate and help to eliminate buzzing if the action is set to a nice low dimension.

   I've built for many fingerstyle players who live in alternate tunings with the "E" string being dropped as low as "C" along with a few other strings being lowered as well so the tension is greatly reduced as is the resistence and ability to function without excessive buzzes beinf present. Some have chosen to experiment with different guage indivual strings to have these guitars in their favorite tunings while still enjoying consistent tension and resistence across the register. If a player likes the tension of a standard light set with a low "E" of .054", he may end up using a low "E" string of more than .057" when it is tuned down to "C" in order to simulate the tension of the standard guage tuned to concert pitch.

   Hope we can get together soon after the holidays.

Kevin Gallagher/Omega Guitars

[QUOTE=Kevin Gallagher]
   I've built for many fingerstyle players who live in alternate tunings with the "E" string being dropped as low as "C" along with a few other strings being lowered as well so the tension is greatly reduced as is the resistence and ability to function without excessive buzzes beinf present. Some have chosen to experiment with different guage indivual strings to have these guitars in their favorite tunings while still enjoying consistent tension and resistence across the register. If a player likes the tension of a standard light set with a low "E" of .054", he may end up using a low "E" string of more than .057" when it is tuned down to "C" in order to simulate the tension of the standard guage tuned to concert pitch.

   Hope we can get together soon after the holidays.

Kevin Gallagher/Omega Guitars[/QUOTE]

I play a lot in alterered tunings mainly DADGad, I grew up listening to Davy Graham live. I firmly believe that the best system for these tunings, after nearly 40 years of experiment, is to use balanced string sets to maintain normal tensions on a dedicated guitar. I use my normal 25.4" scale on a cedar/mahogany OM.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Kevin, are you saying that you change the back angle of the headstock? is it more angle for more tension and less for less?

if so, I would imagine the best setting would be just enough back angle to get a clean note at the nut and no more...

My question is, how low can you go? 10 degrees?

forgive me if i am off track here.
Matt

[QUOTE=John Elshaw] After all the discussion here, I decided to pull the saddle off my Martin OM21 and tune it up a little. First question: what are Martin saddles made of? It definitly isn't any type of bone because it didn't smell in the least when I sanded it down. I took it down a little too low, but I'm not worried because I'm gonna replace it with a real bone saddle anyhow. There were two huge differnces, both of which were expected. First, playability was really increased by less stiffness in the strings, and closer action. It didn't seem to affect intonation at all. Second, there was a HUGE drop in volume of the guitar. I never noticed it much before on classicals because of the low tension nylon strings, but it was really prominant with the steel strings. Time to go start shaping a bone saddle.

Cheers!

John [/QUOTE]

Micarta saddle, corian nut is standard for newer Martins

I would imagine the volume drop is mainly due to the change in break angle at the saddle. Hiw much did you change the action - must have been a fair amount (not surprised - most Martins I see straight from the factory are setup so I can barely play them ). So IMO to ways to get back some angle, and some volume. One, deepen the string ramps from the pin holes to the saddle, amking the string leave the bridge closer to the saddle slot. The other if the bridge is tall enough, is to shave it some. If you can take the bridge down to a height of 5/16, thats pretty much optimal. Otherwise, the neck angle is wrong and it needs to be reset in order to get about 1/8 of saddle showing above the top table of the bridge, and thus improve the break angle.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

The volume drop is most likely because of the lowered action height. The energy in a plucked string depends on the tension and the square of the amplitude: raising the action by a little less than 50% will double the available energy before the string buzzes. This should translate into another 3dB of power output, which will be just barely noticable close up, all else equal, but may translate into more 'carry'. That 'all else equal' is one of the biggest short phrases in the book.

String height off the top can make a difference in the tone owing to the fact that the strings change tension as they vibrate. This signal is basically at twice the frequency of the string, so you'd expect a little 'brighter' sound perhaps, when the saddle is raised.

This has nothing to do with the break angle. So far as I've been able to tell, you don't need much more than about 15 degrees of break angle to stop the string properly; anything more should just be 'gravy'. Many archtops use 11 or 12 degrees and they can play them hard.