# Can someone please help clarify intonation for me?



## stringer (Jun 17, 2009)

Hi all. I hope someone can help me. I replaced the strings on my mij strat with a different gauge and want to adjust the intonation. I've read up about tweeking the nut and the floating trem etc but I need some clarification on step # 2 : "1. Armed with a high-quality electronic tuner, bring each string to pitch. But this time, instead of playing an open string and tuning it, strike the 12th-fret harmonic and tune it to pitch.
2. Starting with the 1st string, play the 12th-fret harmonic and then fret and pluck the same note. If the fretted note is sharp compared to the harmonic, move the saddle away from the neck. Conversely, if the fretted note is flat, move the saddle toward the neck. Make small adjustments—_and retune the harmonic each time you make an adjustment_. Continue comparing the 12th-fret note to its reference harmonic until the former matches the latter." 

What I would like to know is if the harmonic at the 12th fret is supposed to be the exact same pitch as when you tune it as in step 1, or do you just match whatever the 12th harmonic is with the 12th fretted position? i.e. electronic tuner says G but 12th harmonic is a bit sharp so do you set 12th fret pitch to match the slightly sharp harmonic or are they all supposed to be perfect G? Does that make sense?

I have to do this myself as there are no guitar techs / luthiers where I live. NONE!

Thanks folks.


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## zontar (Oct 25, 2007)

You want them to be the same and to be whatever note you tune that string to--so in your example--they should both be the same G


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## stringer (Jun 17, 2009)

zontar said:


> You want them to be the same and to be whatever note you tune that string to--so in your example--they should both be the same G



Thanks buddy. I just got the same answer from a co worker that I just discoverd is a player.

End thread.


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## dradlin (Feb 27, 2010)

The open string and/or 12th fret harmonic will always be the same. You must match either or both of those to the fretted note at the 12th fret.

Move the saddle back to flatten pitch at fretted 12th fret, move it forward to sharpen. Retune the open string after each saddle adjustment.

Use a moderate and consistent pick attack, ignore the initial sharp pitch spike at pick attack but don't wait too long (wait about a second).

Observe how finger pressure at 12th fret and proximity to 12th fret affects pitch, be moderate and consistent.

Many electronic tuners and their readout are only accurate with +\- a couple cents. That will get you functionally in the ballpark but not truly precise.

The guitar should be held in playing position when intonating. Be observant of how hand pressure on neck affects pitch and don't induce errant results in handling.

The process should performed with fresh strings. Intonate after install, and check again a day later after settling.

Strings should be inspected prior to installation. Even the subtlest kink or irregularity along the speaking length of the string will greatly and negatively affect intonation. 

I like to start with the saddle back then intonate it forward. I don't want a kink to form over the saddle then intonate back to expose the kink in the speaking length.

Magnetic pull from pickups can pull the strings out of tune - don't get too close to the strings.

Intonation is the last task performed after all other setup tasks. If your nut is cut too high, neck relief too deep, or action too high, intonation will be negatively affected.


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## LydianGuitars (Apr 18, 2013)

When checking intonation, it is important to check at the 12th fret, but checking at the first 5 frets is equally important.


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## dradlin (Feb 27, 2010)

LydianGuitars said:


> When checking intonation, it is important to check at the 12th fret, but checking at the first 5 frets is equally important.


On the equal temperament tuning, my priority is the octave.

The 5th fret is still somewhat affect by end tension at the nut, and inherent errors designed into the temperament.


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## LydianGuitars (Apr 18, 2013)

dradlin said:


> On the equal temperament tuning, my priority is the octave.
> 
> The 5th fret is still somewhat affect by end tension at the nut, and inherent errors designed into the temperament.


I think you're missing the fact that the intonation can be way off if the nut slots are too high. 

The effect of an improperly cut nut is bad intonation in the first 5 frets or so. Its simple to check and can make a world of difference.


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## Bastille day (Mar 2, 2014)

LydianGuitars said:


> I think you're missing the fact that the intonation can be way off if the nut slots are too high.
> 
> The effect of an improperly cut nut is bad intonation in the first 5 frets or so. Its simple to check and can make a world of difference.


So how does one determine if the nut slots are too high?


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## LydianGuitars (Apr 18, 2013)

Bastille day said:


> So how does one determine if the nut slots are too high?


An easy method is to fret each string at the 3rd fret position and measure the distance between the top of the 1st fret and the bottom of the string. 

To keep things simple, a 10 gauge string should have just enough room for it to go between the string and the fret. Some people go for a smaller gap. Incremental steps in a good idea when making adjustments.

You'll get better intonation and you'll have lower action without fretting out.


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## dradlin (Feb 27, 2010)

LydianGuitars said:


> I think you're missing the fact that the intonation can be way off if the nut slots are too high.


That's an elementary point. I'm missing nothing.

I think you don't know the theory on which the equal temperament tuning system is based.

But I digress...

"End tension", a term I used in a prior post, is the increase in string tension induced when fretting notes close to the nut. The higher the nut slot is cut, the more end tension is induced when fretted close to the nut, and the more notes close to the nut are pulled sharp when fretted.

"End tension" is NOT treated by intonating the bridge, it is treated by compensating the nut.

As an example, the Buzz Feiten Tuning system (I'm a licensed retrofiter) moves the breaking edge of the nut forward towards the first fret a specific measure proportional to the string gauge and scale length. That compensation plus a properly cut nut slot minimizes the effect of end tension.

As I stated in my initial post, intonation at the bridge is performed after nut setup, truss rod adjustment, and action setup at the bridge.


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## dradlin (Feb 27, 2010)

LydianGuitars said:


> An easy method is to fret each string at the 3rd fret position and measure the distance between the top of the 1st fret and the bottom of the string.
> 
> To keep things simple, a 10 gauge string should have just enough room for it to go between the string and the fret. Some people go for a smaller gap. Incremental steps in a good idea when making adjustments.
> 
> You'll get better intonation and you'll have lower action without fretting out.


Equipped with a 10 gauge string and lacking gauged nut files, it is practically a certainty that the nut will be scrapped.

It is far better to use feeler gauges stacked to the fret height plus the desired clearance under the string... with a gauged file cut the slot depth down to meet the top of the feeler gauges. The feeler gauges will ensure that you can't cut too far.


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## LydianGuitars (Apr 18, 2013)

dradlin said:


> That's an elementary point. I'm missing nothing.
> 
> I think you don't know the theory on which the equal temperament tuning system is based.
> 
> ...


Without going with a Buzz Feiten nut, any high nut slots will create issues in terms of tuning and intonation. I think we both agree on this. 
When intonating a guitar, the nut is a key component to look at. A majority of guitars are poorly set up and this is a key area to examine. There's no need for personal attacks here. 




dradlin said:


> Equipped with a 10 gauge string and lacking gauged nut files, it is practically a certainty that the nut will be scrapped.
> 
> It is far better to use feeler gauges stacked to the fret height plus the desired clearance under the string... with a gauged file cut the slot depth down to meet the top of the feeler gauges. The feeler gauges will ensure that you can't cut too far.


Well, there are different ways to do the same thing and of course, nut files are important. 

Perhaps my post was not interpreted correctly. Using a string, you get a known thickness and its easy to feel and see when the string catches between the string and the fret. The string is used only as a means to determine the distance between the bottom of the string and the top of the fret. With a feeler gauge, its a little harder because of the width of most gauges and the string can be lifted without even knowing it. Of course, YMMV and if a different method works for you, then all the better.


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## Jimmy_D (Jul 4, 2009)

dradlin said:


> Equipped with a 10 gauge string and lacking gauged nut files, it is practically a certainty that the nut will be scrapped.
> 
> It is far better to use feeler gauges stacked to the fret height plus the desired clearance under the string... with a gauged file cut the slot depth down to meet the top of the feeler gauges. The feeler gauges will ensure that you can't cut too far.



You have a point with regard to a beginner using feeler gauges kind of like "training wheels" so he doesn't cut too deep, but I'm also sure you know that with experience you can easily use the method Lydian describes as it's been common practice for centuries, I always do it that way and the only measuring devices you need are your hands, eyes and ears, so I think he was speaking from the point of view of someone who has done it more than once...


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## dradlin (Feb 27, 2010)

Jimmy_D said:


> You have a point with regard to a beginner using feeler gauges kind of like "training wheels" so he doesn't cut too deep...


Within the context of this thread (for someone inexperienced) that was precisely my point. Especially when the OP doesn't have a luthier nearby to replace the nut when he cuts too deep.




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## Rudder Bug (Nov 21, 2011)

dradlin said:


> Within the context of this thread (for someone inexperienced) that was precisely my point. Especially when the OP doesn't have a luthier nearby to replace the nut when he cuts too deep.
> 
> 
> 
> Sent from my iPhone using Tapatalk



You don't need to replace a "busted nut". Fill the slot with a drop of CA glue and bone powder. Let cure several hours, sand flush and redo your slot. Easy. Bones are available at a butcher near you.


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## dradlin (Feb 27, 2010)

Rudder Bug said:


> You don't need to replace a "busted nut". Fill the slot with a drop of CA glue and bone powder. Let cure several hours, sand flush and redo your slot. Easy. Bones are available at a butcher near you.


That works as a short term quick fix. The fill material is soft and doesn't wear well and strings tend to bind in it. 


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## Rudder Bug (Nov 21, 2011)

I don't really think so, well I have done some 2-3 years ago and I haven't noticed any deterioration since.


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## dradlin (Feb 27, 2010)

Assist a newbie intonating his bridge and end up debating the longevity of filled nut slots... only at Guitars Canada!



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## Guest (Mar 23, 2014)

Nut files are expensive.
I sand/file the underside of the nut for the right height.
Check/sand/check /sand .. a bit at a time.


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## NGroeneveld (Jan 23, 2011)

here are the required characters...


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## drake (Feb 23, 2014)

Sorry, I saw all of this and I had to chime in.

All of the above points are equally as important as a basic intonation adjustment. The thing I must stress is the tuner. A basic digital tune generally is not accurate enough to do intonation. The basic tuner one can use is an old style VU meter tuner. Generally a Seiko or a Boss TU-80. An inexpensive but deadly accurate solution is the Peterson Strobe Tuner app. $15 but you need the cord to go with it. About $30 from Peterson. When I do setups, this is the basic procedure I follow every time.

1. Remove all strings
2. Inspect frets for wear/flattening. If the is wear/flattening, level frets and recrown. Minimum is polishing. Sand frets with 600 grit and then 1200 grit. Protect the fingerboard with Stewmac fingerboard guards. If guards are not available, mask the fingerboard with green masking tape. After sanding, clean the frets with 0000 steel wool. 
3. Restring guitar and tune to pitch.
4. Check neck relief, adjust as needed. Place fingers on the first fret and the 15th fret. Check the distance between the string and the 8th fret. Should be approximately the thickness of 2-3 business cards at the the fret. Just use the corners of the business cards.
5. Check the distance at the first fret to make sure the nut height is ok. As above, fret the 3rd fret. Should be about 1-2 business cards distance.
6. Check and adjust action. Most of this is done by feel. Just watch the fingerboard radius. But feel free to experiment.
7. Now, intonation. I adjust it by reading the harmonic at the 19th fret and fretting the 19th fret. I find that this is the most accurate position in my experience. Everytime any adjustment is made, retune. You will be retuning a lot. 
8. After you get these adjustments to match. Play a few chords. Major bar chords work well. And as you move them up the neck, You can hear of the chord starts to "warble". If it warbles, double check the intonation again, and make necessary adjustments. 

I do all of my intonation adjustments with the instrument in my lap in a standard playing position. This avoids issues with undo pressure on the neck (neck rests) and the adjustments hold when playing. 

Hope this helps, and is not too daunting.


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## dradlin (Feb 27, 2010)

drake said:


> 7. Now, intonation. I adjust it by reading the harmonic at the 19th fret and fretting the 19th fret. I find that this is the most accurate position in my experience. Everytime any adjustment is made, retune. You will be retuning a lot.


The natural harmonic occurring at the 19th (and 7th) fret is a "just" perfect fifth and is defined by approximately 702 cents.

The fretted note at the 19th fret is an "equal tempered" imperfect fifth and is defined as 700 cents.

By design, there is a 2 cent error between the 19th fret natural harmonic and the fretted note at the 19th fret. That is assuming no other induced errors.

The same thing happens with the perfect fourth natural hamonic at the 5th and 17th fret versus the fretted note... a 2 cent error.

The only error free interval in the equal temperament system (on which a guitar is based) is the octave or unison note. So if on a guitar you tune or intonate using an interval other than the unison or octave, you will be inducing at least a 2 cent error.


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## drake (Feb 23, 2014)

"I find that this is the most accurate position in my experience."

With the measurement taken at the 19th fret, audibly, I've found that the intonation is far more pleasing than taking it from the twelfth fret. I admit, when one takes it down to harmonic measurement, it will always work out as slightly off. Intonating is an art that all technicians try to perfect with time. 

A guitar, by design, does not perfectly intonate, by the text book term. In my experience and training, a well intonated instrument will play cleanly through intervals. This allows the chords to chime together and octaves to play without oscillation. If you take a good tuner to just about any guitar, brand new, one will find that the fretted notes up and down the neck will have slight variations in pitch.


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## stringer (Jun 17, 2009)

Wow! Everything you wanted to know about intonation but were afraid to ask. Last time I looked there was only 1 page to this thread. Thanks everyone for your input. I had never heard of intonation @ the fifth fret, looks like I'm still not finished! A lot of this stuff is over my head, but it is definitely teaching me a thing or two.


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