Official Luthiers Forum! :: View topic - String Length/Scale Length Whats it all about

Well in my attempt to get a feel for designing an archtop, I have been looking at different models of guitars trying to use pixels to estimate their dimensions. I have been looking at the scale (we'll say it's 25") and counting the pixels between the bridge and the nut, then dividing the number of pixels by 25. This gives me how many pixels is one inch so I can measure from there. While reading this, it occured to me that my measurements are off. I assumed that the middle strings were to closest to the actual string length, but I'm not sure if that's right. I mean they are the shortest distance to the nut, but if I'm understanding this right, that assumptoin is wrong. So, is the length of the high e string closest to the actual length between the bridge and the nut since it's the thinnest?

Author:	johnwalkerwaldsmith [ Tue Feb 09, 2010 9:08 pm ]
Post subject:	String Length/Scale Length Whats it all about
Im currently going to roberto venn luthire school in tempe az, learned about string length today and im trying to wrap my head around it, I know that the string length is 1/16 more than the scale length... I just dont understand why this is.... or why it is.... anyone know?

Author:	bluescreek [ Tue Feb 09, 2010 9:34 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
actually the working length of the string is varied to each string . When we talk about scale length we are talking about the placement of the actual frets on the board. Now to manage intonation we have to match the working length of the string to the scale. Strings when they are plucked do not vibrate in nice graceful arcs but can look rather ungainly. If you look at a steel string guitar you will see the saddle is at an angle. This angle is about 3 degrees. This makes the 6th string 1/8 of an inch longer than the 1st. We will also compensate the length of the 1st string to the scale length. You will never get any fretted instrument to be perfectly intontated on every fret. You do the best you can by matching the players style to the set up. Next we look at what can influence the intonation . Action height is obvious , string gauge , and age. Fret height , and how hard you fret. It is important you understand all this so when you are setting up a guitar you can match the players style to the placement and compensation of the saddle . A blue grasser will attack the strings harder than a fingerpicker. With a higher action , the string will tend to be pulled sharp so if you are building a bluegrass guitar you may want to add a bit more in comp length and use a wider saddle to allow you to compensate the saddle for better intonation.

Author:	johnwalkerwaldsmith [ Tue Feb 09, 2010 9:57 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
thanks! im going to read this a few times to get a better hold on it, we are actually talking about electrics right now but its good to see the point of very from an acoustic at the same time.... i was thinking the string length thing is less important on a electric because you have at least a 1/4 inch adjustment on the saddles.... am i thinkin right about that?

Author:	johnwalkerwaldsmith [ Tue Feb 09, 2010 9:59 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
thanks! im going to read this a few times to get a better hold on it, we are actually talking about electrics right now but its good to see the point of very from an acoustic at the same time.... i was thinking the string length thing is less important on a electric because you have at least a 1/4 inch adjustment on the saddles.... am i thinkin right about that?

Author:	enalnitram [ Tue Feb 09, 2010 10:00 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
so the question is really about compensation. don't thinner strings begin vibrating closer to the saddle than the thicker strings do? I thought that's what it was. if you could be a little bug crawling on the strings you'd see (or feel) that the strings are stiff near their end points.

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Author:	enalnitram [ Tue Feb 09, 2010 11:32 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
johnwalkerwaldsmith wrote: is the whole string length thing all about compensation? I guess that's what i'm trying to figure out in your op. you said, "I know that the string length is 1/16 more than the scale length... I just dont understand why this is". did you mean to say, "1/16th inch more?" ... if so, it was a question about compensation. your question is all about compensation, i think. the whole scale length thing is a topic that includes compensation, but there is also more to it than that. it's not all about compensation, it's a part of it. string lengths need to be a little bit longer to allow for compensation. http://books.google.com/books?id=9CRSRY ... #v=onepage

Author:	Yukon [ Wed Feb 10, 2010 1:25 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
Imagine you have built the ultimate low action electric shred machine. In your brilliance, you have figured out how to have the strings actually lie right on the frets for the entire length of the fingerboard and yet still play clean. Since you do not have to press the strings down to the frets to sound a note you are not stretching the strings at all. You simply touch a string at a fret and voila, a wonderful clean note rings out. Okay, this is likely impossible but in this scenario your guitar needs no compensation - the scale length and the string length are identical. This means that the saddle(s) are parallel with the nut and are exactly twice the distance away from the nut as compared to the distance between the nut and the twelfth fret. Your saddles are set at point that is exactly the scale length of your guitar The sun is shining, the bills are all paid, and the Noodles are still playing at old Nita's Hideaway. On to the real world. You've got to have a little bit of room between the strings and the frets to make your guitar sing like an angel, or if you prefer scream like a demon. Three things have to change. John Reuter, bless his soul, has already told you about the order of all things neck, saddle, and nut. Each of these must be adjusted to get your guitar playing great. First you add a little relief by adjusting the truss rod, then you set the height of the saddle, and finally you set the height of the nut slots. Each of these steps has combined to create what we call the action of your guitar. So now your strings are not lying on the frets but are suspended above them. In order to fret your note, now you have to push the string all the way down to the fret. What does that do to the string? Right on - the string gets stretched. When the string is stretching down to the fret under your finger, the note that it is 'going' to make is being sharped right up until it touches the fret and it's the note you want. When else does that happen while you're playing? Exactly, when you are bending a note! You push a string across a fret, sharping it until you reach the note you want. Wow. I've been going on a while. By the time I finish this somebody smarter will probably have given you a better answer. Hang in there. We're getting to the cool part. So when you set your action you did three things - adjusted the truss rod, adjusted the saddle height, and set the height of the nut slots. But your saddle(s) is still set at a point exactly twice the distance from the nut to the twelfth fret. With everything else set up right, when you fret the string your note is going to be sharp. That sucks. You want the note to be right. What do you do? Well, you move the saddle away from the nut of course, because the further apart the nut and the saddle the easier it is to press the string down to the fret which means less stretching which means less sharping. So you move that saddle back until the fretted note is what you want it to be. What you're doing is making the vibrating part of the string (the part between the nut and the saddle) longer. That's the difference between scale length and string length. And the difference you created is called the compensation. If you made the string too long (saddle and nut too far apart) you'd notice that your fretted notes are going to be flat, so you make it shorter! Find an old crappy archtop with a moveable bridge and mess around with the bridge placement while comparing the open string note to it's twelfth fret note. In no time you're going to be a master of this mind-bending question of string length and scale length. Please give the folks at Roberto Venn my regards and good luck to you. Yukon RV Fall 2002

Author:	Alan Carruth [ Wed Feb 10, 2010 3:51 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
Thanks Yukon. I'll just point out that, as you already know, the amount that a string bends, and the compensation that it needs, depends a lot on the string. A nylon E string is hard to bend because it's so stretchy, and doesn't need much compensation. A plain steel G string, which is pretty slack and doesn't stretch much, will bend a lot and needs a lot of compensation. In the end, it's all about trying to get the guitar to play every note in tune. It's impossible, but we still have to try.

Author:	Yukon [ Wed Feb 10, 2010 5:09 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
As Al said, there are countless variables depending on the instrument, the gauge of strings, the kind of strings, setup preferences, playing style, etc. You can look at my description as a general rule of thumb if you like - a jumping off point.

Author:	Howard Klepper [ Wed Feb 10, 2010 7:01 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
If your teacher hasn't made sense of compensation, do the rest of the class a favor and ask for a better explanation. You are at a place where they are supposed to teach this stuff.

Author:	bluescreek [ Wed Feb 10, 2010 7:51 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
Howard has great advice. if you are paying for the class , your instructor needs to get this point across so you understand it .

Author:	johnwalkerwaldsmith [ Wed Feb 10, 2010 10:48 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
THANKS A BUNCH, I will be sure to let them know you say hi, and i did ask and get it now, I was just at home and thinking about it and still didnt really get it and wanted to know NOW, haha thanks alot though

Author:	Robbie_McD [ Thu Feb 11, 2010 8:35 am ]
Post subject:	Re: String Length/Scale Length Whats it all about
This document is a pretty decent overview of string length/intonation: http://www.lmii.com/CartTwo/Intonation.htm

Author:	Yukon [ Thu Feb 11, 2010 8:42 am ]
Post subject:	Re: String Length/Scale Length Whats it all about
That's great John, anytime you have a question feel free to come back. You will get lots of opinions to mull over. Be sure to tell your buddies at RV that this can be a good resource. You can also reach me directly at yukonarizona@mac.com I had a great time at RV and it was the first step in what has become a successful career in guitar repair.

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Author:	Lemagr67 [ Fri Feb 12, 2010 7:47 pm ]
Post subject:	Re: String Length/Scale Length Whats it all about
Well in my attempt to get a feel for designing an archtop, I have been looking at different models of guitars trying to use pixels to estimate their dimensions. I have been looking at the scale (we'll say it's 25") and counting the pixels between the bridge and the nut, then dividing the number of pixels by 25. This gives me how many pixels is one inch so I can measure from there. While reading this, it occured to me that my measurements are off. I assumed that the middle strings were to closest to the actual string length, but I'm not sure if that's right. I mean they are the shortest distance to the nut, but if I'm understanding this right, that assumptoin is wrong. So, is the length of the high e string closest to the actual length between the bridge and the nut since it's the thinnest?

Author:	sttelnoj [ Fri May 28, 2010 6:03 am ]
Post subject:	Re: String Length/Scale Length Whats it all about
Lemagr67 wrote: Well in my attempt to get a feel for designing an archtop, I have been looking at different models of guitars trying to use pixels to estimate their dimensions. I have been looking at the scale (we'll say it's 25") and counting the pixels between the bridge and the nut, then dividing the number of pixels by 25. This gives me how many pixels is one inch so I can measure from there. While reading this, it occured to me that my measurements are off. I assumed that the middle strings were to closest to the actual string length, but I'm not sure if that's right. I mean they are the shortest distance to the nut, but if I'm understanding this right, that assumptoin is wrong. So, is the length of the high e string closest to the actual length between the bridge and the nut since it's the thinnest? string scale is measured using the high or low E strings. due to the string stretch compensation talked about earlier, there is no 'right' placement for your bridge. its just a case of a healthy balance or fully adjustable saddles.