Nut compensation

[Roger Häggström]

This is the last installment of my trilogy containing the "composite saddle bone", the "spruce bridge plate" and now the "nut compensation".  These three things works in harmony on my restored old guitars and to my ears gives them a way better sound than expected :-)

Intonation is a field with many theories and opinions. Here I describe a practical way to use the nut and not just the saddle to improve intonation on any fretted instrument. The information found in the site setitupbetter.com is the base for the method.

To use the nut for intonation purposes gives the possibility to have almost "perfect" intonation on two different spots on the fretboard. With standard intonation the intonation will be great at the 12'th fret only. The intonation in the upper fret area of the fretboard are really bad indeed. Incidentally, that's where the majority of all guitar players play their chords ;-)

The main problem is that all fretted notes have a higher pitch than the open strings due to the stretching of the fretted strings. Another major problem is the need to have the nut a bit higher to avoid fret buzz from open strings (they are longer, vibrates more and are often played harder than fretted notes, back buzz behind a capo is another problem). Chords with a blend of fretted notes and open strings will sound out of tune with the standard intonation, especially the chords taken near the nut.

After reading the info on the site mentioned above, I came up with a way to measure the intonation points in the nut and the saddle. Using the measures I then cut the fingerboard shorter (around 1 mm shorter) at the nut and use a dremel and files to shape the nut and saddle so the string leaves the nut/saddle at the measured intonation points.

I use a stroboscope tuner and use it to make sure that the open string, the fretted third and 12'th notes on each string is in tune. I do this by moving the intonation points at the nut and saddle to a forth (retuning after every movement) until the equation is solved and all the three notes on the string is in tune. The positions are measured and written down.

While measuring, the "nut" consists of small bits of tangless frets acting as an adjustable "zero fret" and the "saddle" is the back ends of drills rolling on top of the bridge. A temporary tailpiece is used to fasten the strings. A small piece of spruce is used to make the fretboard a bit longer at the nut to make room for the movable frets, a 0.15 mm feeler gauge gives the "nut" a bit more height to emulate the optimal string height at the 1'th fret. Another piece of spruce is needed to fill out the saddle slot if there is one.

It's easier on an electric guitar, no need for a tailpiece and drills.

The final intonation points on the electric guitar above. Small compensations on the nut was needed on this one, but I had to extend the width of the nut about 1 mm closer to the 1'th fret.

I measure the distance from the back side of the 1'th fret to the middle of the "zero" fret for each string with a digital caliper and the distance from the same backside of the 1'th fret to the intonations point at the saddle with a ruler. I put the measurements in a table (mm and cm).

It's important to check the string height at the 12'th fret, it shall be the one used when playing. For the electric guitar I use a standard 2,5/1,5 mm between the top of the fret to the underside of the string. Having the stringset that the player likes and will use is another good thing to make the intonation as good as possible. The tuning shall be the one most used when playing. The fretboard should have the right relief too. In a nutshell, all the setups and choices should be done before the measuring for intonation.

By cutting the fretboard shorter at the position for the intonation point closest to the 1'th fret, the nut can be rectangular and all the other intonation points can be reached with a dremel. The nut looked like this when cut. Only with a close inspection of the nut you will notice the jagged cuts.

Not a great example, the G and D came close and I decided to leave both of them uncut when measuring the nut blank on the guitar... I should have cut in 0.16 mm on the G string...

Every guitar have small variations of the intonation points. There is no "one size fits all".

On acoustic guitars I have noticed though that it's the A or b strings that usually comes closest to the 1'th fret. At the saddle the strings G-e is often a straight line and the E-D strings can vary a lot. The electric guitar example above is not typical, the variations at the nut is usually bigger.

I made a special tool to shuffle the fret bits at the nut like this.

I found a drill bit set with drills in steps of 0.1 mm between 6 mm to 0.1 mm. Very handy to adjust the string height at the 12'th fret with a radiused fretboard. I mark the position of the intonation point on the nut blank with small bits of tape to make it easier to cut in to the right spot.

I made a jig for the Dremel using my modified version of the Stewmac saddle slot jig.

Here is the finished nut, a rather typical one for an acoustic guitar.

Doing a nut compensation like this makes the guitar chords near the nut play beautifully in tune. I believe that even a capo will play better since the saddle is only intonated for fretted notes (as the capo is) instead of a blend of fretted notes and the problems at the nut!

Without a nut compensation, every fretted instrument WILL be out of tune when playing chords near the nut. The difference is is a major one.

The nut intonations is quite stable. The intonation is very good even when a different set of string gauges or alternative tunings are used. I for one is not as sensitive to pitch as the stroboscope tuner is! On an electric guitar it's always a good thing to intonate the "good old way" for the new set of strings, that will make the guitar play cleaner in the lower part of the fretboard. There are always variations between different sets of the same string brand, but most of the time the difference is small.

The measuring process usually take me one hour. Making the compensated nut and composite saddle another couple of hours. All in all, it's about a half a days work if nothing goes wrong. The upside is the result obviously, but the measurements also makes it impossible to cut the saddle slot in the wrong position :-)

[Roger Häggström]

Looks like Earvana and Music Man had a legal battle over a nut compensation patent. No such patent should be granted, people have done this forever. And both of them had it all wrong... Earvana won in a rather amusing way, read all about it here!

https://thepatenttrade.wordpress.com/2013/02/21/heres-a-nutty-case-...

[Christopher Parker]

It seems that identical instruments with the same string gauge and scale length should be compensated identically. Right? It occurs to me that if you were to use a wound G string you would have to change the compensation as well.

I don't care to read about the patent lawsuit between Earvana and Music Man, because I find it infuriating that companies are granted patents for things they did not invent. Neither Earvana nor Music Man invented the compensated nut, so it's absolute BS that either should be granted exclusive rights to the idea. Furthermore, Ralph Novak did not invent the fanned fretboard either so why should I have to pay him for making one? I think Buzz Feiton has a patent on the "advanced" nut, (regular nut moved forward a small amount). He did not invent this concept either. These patents should not exist. To be fair, the above concepts should be public domain. But the law has nothing to do with fairness and it never has.

[Roger Häggström]

The assumption seems logical, but my experience is that in real life every instrument have variations in the compensation pattern. I see common trends (A and/or b strings closest to the 1:the fret, b closer than e, D closer than G etc.), but the pattern is never identical on different instruments with the same setup and strings. Why it's like that I don't know. I do different guitars all the time, maybe the compensation pattern is more similar between guitars of the same model and maker. Wound or plain G strings are compensated differently.

In the very first book about guitar building from 1830 there was a good advice to "cut the fretboard shorter at the nut" :-)

I agree with the fact that no patent should have been allowed for this.

Please read the link I provided. It's great fun if you like some mathematical humor!

[Christopher Parker]

Well, if the distance from bridge to nut is the same, and the distance from the nut to the first fret is the same, the only variable is the strings, so (assuming you're going for identical results) the amount of compensation would be identical unless your strings are not identical.

What is the title of the "very first book about guitar building"? I would like to read it.

I read the article about the patent dispute. I guess the court doesn't care who invented the concept - they only about who registered the patent first. I think I'll see if I can register a patent for the wheel. Maybe nobody's thought to do that yet. 

[Roger Häggström]

The assumption seems logical, but maybe something in the woods make a difference. I have yet to do a nut compensation of two brand new lookalike instruments of the same brand. I don't know. The mensur is a major factor för the compensation and I work with a plethora of them, 59,5 cm to 65 cm.

I wish I knew. Some time ago this fact came up in a discussion and I remembered it. Made a Google search and maybe it's "Methode por La Guitare, Ferdinand Sor" from 1830. I found a PDF file but unfortunately I can't read French.

I though the mathematical reason to deny Music Mans patent was hilarious, I know about the Fourier series from school. Every continuous periodical function can be described by a set of sinus waves with different amplitudes. A mathematician would ROFL!

[steven gallagher]

>> Every continuous periodical function can be described by a set of sinus waves with different amplitudes.

Actually, you need sine and cosine waves. And the function doesn't have to be continuous; the first example they teach is usually a square wave. 

[Roger Häggström]

There you go :-)

[Ron Frazier]

 A long time ago I read in the American guild about some one compeced the nut and he said that it was in tune better but no one would play with him as it wasent in tune with them!

I read some where that Willie Nelson has to use several sets of strings to make up a set that will play in tune.

Back in the days when every one talked on the  CB radio it had a delta tune dial you could tune the one you were talking to to come in clear. I upgraider my radio to a ham radio and no one would talk to me any more . I found out that cb radios had a transmit  cristle for transmit and one to receive and each one could be off by sever frecincreys so you used the delta tune to correct them.  My ham radio transmited  and received on the same frencey !

I am not a profesinal player and I tend to grip the strings harder when I want to play louder and it plays out of tune! I think our tecknick needs worked on.

Ron

   

[Hesh Breakstone]

Roger no offense intended but nut compensation is bull shit if one would simply cut the nut slots properly.....  

On your Strat nut the slots are WAY too high and anyone fretting in the first five positions or so will surely pull the string sharp  since the nut slots are so very high.

I do set-ups every day and often 4 - 6 of them and this has been my life for a decade now.  In example after example I have yet to have a client, all guitars that I repair are client guitars I don't work for a store, who was not happy as a clam with the improvements resulting from simply cutting the nut slots very low and properly.....

Not here to argue nor will I but in my considerable experience even with clients reading some BS on the Internet and then specifically asking for/about nut compensation I have yet to have a client who was not completely satisfied with a well cut nut with no compensation.

We have an expression in the states and this is not by any means directed at you and it's called KISS.  KISS stands for keep it simple stupid...;)

I suspect that I would make more money if I just gave folks what they asked for and compensated nuts when asked but my clients see my business partner and I as "trusted advisors" and as such we have a duty to be ethical, honest, and good stewards of our clients dollar (your currency may vary).  With this said we don't do nut compensation and I'll add that my business partner is trained in one of the big compensation names and he thinks it's bull shit too.  

Our shop is pretty busy and again with NO music store work we service over 1,100 instruments (all plucked, stringed) annually with only 2 Luthiers.  We maintain a five star rating with Facebook, not easy to do I will add.... with dozens of reviews.  I'm mentioning this because we have no time or patience for snake oil and there sure is a LOT of it in the Lutherie trade....

I appreciate your sharing but please be advised that there is not agreement that things such as nut compensation have any value what so ever.....

Happy Holidays to you as well.

[Roger Häggström]

I know intonation is a minefield topic filled with opinions. Maybe because people are not hearing the same thing. Some people are very sensitive to intonation problems, others simple don't care or even likes the guitar to sound a bit "off".

The intonation problems at the top en of the fretboard is very dependent on the extra string height over the 1'th fret (compared to the height given by a zero fret of the same height as the 1'th fret). The lower you get, the less the intonation problem. If you play soft you can have the height as low as from a same level zero fret, if you play hard you need some extra height. With a low action at the nut combined with a straight nut moved about 1 mm closer to the 1'th fret from the theoretical position the intonation will be good. Really. But not as good as it could be.

There is nothing wrong with the physics. With an intonated nut you can always get better intonation at the top frets and the whole fretboard too. The question is if the individual player needs it and if it's worth the extra work.

The intonation problems is less of a problem on electric guitars due to the lower action and string height on both ends of the string. An electric guitar is also simpler to intonate the standard way.

If you like me is an acoustic guitar chord player the effect of a good intonated nut is great, not so great if you are a single string melody and solo player. I would say that cheap acoustic guitars used by beginners using the standard chords near the nut would benefit most of an intonated nut.

I do like to keep things simple. But for me the great intonation you get from an intonated nut using the method I describe is well worth the effort. I did my first intonated nut because I was curious about it. I didn't expect anything, the vote was out. After playing a minute or two I knew that this was something I must have on my guitars. The method I describe above is easy enough to follow if you are as curious as I was.

I ask customers if they want to have an intonated nut (and composite saddle bone). Most of them are curious or have played another old guitar of mine, they usually say they will have both.

As for the string height at the 1'th I might be on the hight side on the electric guitar coming from the acoustic world. I have 0.4 mm between the top of the fret to the underside of the E/A/D strings and 0.35 mm for the G/b strings and 0.3 mm for the e string (measured with feeler gauges). Would be interesting to hear your numbers.

[Christopher Parker]

Hesh makes a valid point here. Nut slot depth is arguably the most critical adjustment on the guitar. A couple thousandths of an inch too low, and the open notes will buzz, a little too high, and the action is uncomfortably stiff, and the open chords play out of tune. A tiny change in slot depth makes a huge difference in terms of playability and open chord intonation.

Looking at your pics again, the high E of the strat nut is definitely too high to play in tune. If you leave all your slots that high, it's no wonder why you think nut compensation is necessary.

The nut slots should be cut so that the strings are about as high as they would be if they were laying on a fret - or maybe slightly higher, depending on the player's expectations. Most players are sensitive to open string buzzing, so I usually allow a slight amount of margin. Unwound G strings can be particularly prone to buzzing, and some players play open notes hard and expect them not to buzz. Plus, the nut could wear more quickly than the frets, so there's another reason to leave it a few thousandths high. As with many things, I determine the final adjustment based on the player's technique. A heavy handed blues player's nut doesn't get slotted as deep as a metalhead shredder's.

Perhaps the reason you're not getting consistent results with your compensation form guitar to guitar is due to variances in slot depth. But if you actually slot the nut to proper depth, you might begin to re-think the entire premise of whether nut compensation is even necessary. 

Another cause of open chord out of tune-ness is if the first fret is left high. This is a very common problem on factory built guitars, and guitars that have had their frets dressed by someone who is inexperienced or unskilled. A high first fret will cause the action to feel stiff even when the nut and everything else is adjusted properly. If the high first fret is left undetected, the resultant tuning problems could lead one to believe that a compensated nut is necessary, just like they would if the nut slots were left too high.

There are only two types of players who I will build a compensated nut for - a slide player who needs their nut left high, but wants their open chords to still play in tune, or a heavy handed player who has given up on ever achieving proper technique. Everyone else does just fine with a properly slotted traditional nut.

[Hesh Breakstone]

Thanks Christopher - I completely agree with you and appreciated your comments.