intonation primer

[tippie53]

When setting up a guitar , how can I be sure I will have good intonation?
This is a common question and one that has many answers. I hope this explanation will help you understand what it is and how you can make the best adjustments for your situation
1st , What is intonation?
This is matching the strings working length to the static length of the frets on the fret board.
2nd How can I do this ?
First you have to understand and control the individual variables and since this is individual to each guitar you need to identify them so you can control them. so lets look at this and follow the stages of what we can do.
First there is a lot to do with the prep of the fretboard. The fret board needs to be as true as you can make it. Once installed on the neck you need to place the saddle carefully as possible. I like to measure nut to 12th and double that . Then following the 1st string ( hi E ) and I add .100 to that to the saddle slot center. I then add .125 for the bass side.
The typical bridge as a 3 degree compensation angle . To help your intonation set up you can look at saddle placement or saddle thickness a way to help make adjustments for the saddle to get your intonation as close as you can. The wider the saddle the more adjustment you would attain , to a point.
The next point would be what is your normal action height , a flat picker may need more height than a finger picker , the more height the easier it is to pull the string sharp.
You have to accept that you will not have perfect intonation on every fret , so you want to do the set up the guitar to the players style. So lets look at this from the extremes , a blue grass flat picker and an easy finger picker

FINGER PICKER Light Intonation adjustment
In the case of the lighter player I may use a 3/32 saddle figure a light 2-3 action
this means 2/32 and 3/32 action height on the 12th fret. Here I will want to set things up as to my players style , so the higher up the neck I want to be sure I take that into account.

I set the bridge as state with a 3/32 thick saddle. I put a .125 radius on the top of the saddle , I check in this order
1 relief ( .006 at the 6th fret ) This is the line from the 1st fret to the 12th fret.
( I set something under the nut set 10 to 12 lb on the guitars shoulders to simulate string tension and keep this on until I add strings )
2 set the nut slot ( .010) off the top of the fret plane
3 using a straight edge resting on the 1st fret and on the saddle , measure the height at the 12th fret. This is following the line of the 1st and 6th string. Then I can make the rough saddle.
Now I can string the guitar. I like to string with the same gauge string the customers want to use. Once strung I check the adjustments.
I like to set the relief again and now I can adjust the nut slot. I will take the nut slot to .006 over the fret plane and tune to pitch. We are assuming the frets were dressed and ready for stringing
Now with the strings tuned I can check the action height and adjust the saddle then I check the harmonics on the 1st and 12th fret. I do want to see within 3 cents on intonation on a raw saddle. I do not mind seeing a touch flat as the ear tends to pick up sharp faster than flat.
Now I can , if I have to adjust the saddle to each string. Another reason I don't mind seeing a touch flat , is that players will often pull on the string and this can pull the string sharp.

On a blue grasser I will keep the nut about .007 to .010 with relief of .06 to .010 . This situation I tend to work with a thicker saddle . I also set the action here at 2 1/2 64th and bass on 3 1/2 64th. I prefer a .110 saddle . I do that same process of relief , nut and saddle. , then adjust the intonation. While most blue grassers tend to play in the 1st position, you still want to do the 1st and 12 fret. A hard flat picker may have a heavier fretting hand so it allow 3 cents flat on intonation on 12 fret and use a light touch when adjusting. That permits the player some fretting pressure . The closer to the fret you touch the less you pull sharp the farther back the more it will pull sharp , Try it , you will see.
I hope this information helps you.


john hall

[Nick]

Thanks for posting this John & imparting knowledge from your years of setting up the various style of guitars. Useful info & numbers to add to the forum for anybody wanting to understand their technique or coming to grips with their first few builds. Do you tweak the numbers for different string gauges or are your numbers a good general rule of thumb?

[tippie53]

EDIT POINT
on the last section I stated 2 1/2 64 and 3 1/2 64
please change that to 2 1/2 / 32 and 3 1/2 / 32
thanks gad you like it

[Dominic]

Thanks John. A bunch of us have been developing techniques from Trevor and Gerard’s book which apply increasingly sophisticated maths to the problem and takes account of the properties of different brands of string which have an effect on the final sound. Using the traditional methods only the open and 12th frets are in turn and everything else is either off a bit or off a lot. These are charted in the book as cents deviations from each note up the fret board for each string. It is an eye opener how bad it is seeing the results in a chart.

Using the these more sophisticated techniques the cents errors can be reduced to almost nothing at each fret and adjusted for playing style, action, relief and frets.
A lot of this is discussed in the Gore section of the forum.

Despite what the old timers hanging around forums, Australia uses the metric system so it would be good to do this in mm next time. Hopefully the US will catch up with the rest of the world on this one day.

Cheers
Dom

[Nick]

Thanks John. A bunch of us have been developing techniques from Trevor and Gerard’s book which apply increasingly sophisticated maths to the problem and takes account of the properties of different brands of string which have an effect on the final sound. Using the traditional methods only the open and 12th frets are in turn and everything else is either off a bit or off a lot. These are charted in the book as cents deviations from each note up the fret board for each string. It is an eye opener how bad it is seeing the results in a chart.

Using the these more sophisticated techniques the cents errors can be reduced to almost nothing at each fret and adjusted for playing style, action, relief and frets.
A lot of this is discussed in the Gore section of the forum.

Despite what the old timers hanging around forums, Australia uses the metric system so it would be good to do this in mm next time. Hopefully the US will catch up with the rest of the world on this one day.

Cheers
Dom

Don't consider myself as an old timer Dom ( although some may beg to differ) and being a practical engineer, I use the metric sytstem all day long but strangely still use imperial when working with scale lengths. I don't find switching between the two to be a problem. At the end of the day, does it matter?

[ozwood]

I'm Not Fussy , not to hard to convert, just gratefull for the handy tips that John and others share so generously.

Thanks John.

Cheers,

[Bob Connor]

I tend to use everything as well.

Even been known to use cubits on a bad day. (that'd be the Egyptian Royal cubit - not the Biblical cubit)

Regards

[ozwood]

Even been known to use cubits on a bad day. (that'd be the Egyptian Royal cubit - not the Biblical cubit)

BOB , This is God , thou shalt build a Weissenborn 200 cubits long and 90 cubits wide , and shall fill it with two sets of every kind of tonewood , exept Qld Walnut cause that smells like shit !
.

Cheers,


(I know you said the egyptian one , but that had no comic value)

[Nick]

Even been known to use cubits on a bad day. (that'd be the Egyptian Royal cubit - not the Biblical cubit)

BOB , This is God , thou shalt build a Weissenborn 200 cubits long and 90 cubits wide , and shall fill it with two sets of every kind of tonewood , exept Qld Walnut cause that smells like shit !
.

Cheers,


(I know you said the egyptian one , but that had no comic value)

[Kim]

I tend to use everything as well.

Even been known to use cubits on a bad day. (that'd be the Egyptian Royal cubit - not the Biblical cubit)

Regards

Philistine!!!

The Egyptian Royal cubit is an inaccurate bastardisation of the 'Sumerian' cubit. It came about when the ne’er-do-well, Pharaoh Djer had been picking his nose by the banks of the Nile and was surprised by a bare footed Nubian nymph who had introduced herself by warned him that his head may cave in if he was not careful. To negate the embarrassment of the moment, Djer had explained to the maiden..:

"This is not how it looks nymph. The fact is I’ve just been taking some very important measurements of the rising river Nile in order to project the extent of this seasons flooding of our rural lands and thus determine the potential productivity of our upcoming harvest from which some insight into what the market worth of our kingdoms current grain stocks may be."

To which the nymph had replied: "Sort of like trading in futures then?"

To which Pharaoh Djer had replied: "Well yes, sort of"

To which the nymph replied: "So why did you have your index finger up your nose then?"

To which Djer had replied: "Well, as you should know, or would had you gone to an ‘Egyptian’ school. The units used for the measurement of mid length within our region of the globe have traditionally been the 'Sumerian' cubit, being the distance from ones elbow, to the tip of the index finger. This system has served us well for general day to day construction of pyramids and arks and stuff. However research has shown that anatomical variations from one individual to the next can result in huge discrepancies of the bottom line when economist are attempting to calculating the entire GDP of a nation."

To which the nymph replied: Yeah??? So why were you picking your nose??

To which Djer had replied, with a sigh....: “Well as I had just tried to explain you stupid woman, there is a general inaccuracy of app 6mm in the unit formation of Sumerian cubit caused by anatomical variations from one individual to the next. What you just witnessed when you had come sneaking up on me just now was not me picking my nose as you had so hastily assumed, but rather, being that I am a quite tall man, was the application of a clever new system of standardisation to the Sumerian cubit called the 'Royal' cubit. In this ‘new’ system, should one be tall like me, and therefore have a slightly ‘longer’ forearm than a shorter man, the anatomical variation error of the Sumerian cubit is accounted for by placement of one’s index finger up one’s nose by app 6mm thus eliminate that variation”

To which the nymph had relied” “Oh…Sorry, just goes to show.. Hey where’s the nearest Office Works around here? My printers’ all out of papyrus??

To which Djer replied: About half a mile north up the cycle path, just follow your nose, you can’t miss it.”

To which the nymph asked crossly: Are you saying I have a big nose??

She then left in huff leaving Djer to mumble…. “Stupid woman, no wonder she can’t afford a pair of sandals”

Cheers

Kim

[Dominic]

Yeah yeah, I have a link to a conversion site and we can do it. But surely it would be better that a tutorial in the ANZLF be given in metric as that is what we use here. Put in the old measurements for sure but making me convert numbers to make sense of it is only doing half the job.

It is electronic colonialism. That MS word keeps trying to make me spell labour as labor no matter how many time I tell it I am not a seppo is frustrating enough.

So how about, if seppos want to post tutes here, to be a little more useful to all of us rather than a few, publish both metric and imperial. It would also show a little cultural sensitivity.

Cheers
Dom

[Nick]

Yeah yeah, I have a link to a conversion site and we can do it. But surely it would be better that a tutorial in the ANZLF be given in metric as that is what we use here. Put in the old measurements for sure but making me convert numbers to make sense of it is only doing half the job.

So you really want, is somebody else to go to the trouble of doing what you can't be bothered with, is that what it really boils down to?

It is electronic colonialism. That MS word keeps trying to make me spell labour as labor no matter how many time I tell it I am not a seppo is frustrating enough.
So how about, if seppos want to post tutes here, to be a little more useful to all of us rather than a few, publish both metric and imperial.It would also show a little cultural sensitivity.

Cheers
Dom

Just as you have done in those few sentences you mean?

[ozwood]

Maybe we should dock his pay if he's only done half a Job........................................... aww that's right we don't pay to use this site and John provided the Info for free.


Regards,

[Bob Connor]

But surely it would be better that a tutorial in the ANZLF be given in metric as that is what we use here.

Cheers
Dom

Metric is what YOU use here Dom. My fingerboards are 24.9 inches or 25.4 inches and my backs are around .090". So I use imperial as does just about all of rest the steel string guitar building world.

I also feel that referring to citizens of the USA as seppos is downright rude and our brethren from across the Pacific deserve an apology for such a culturally insensitive diatribe.

[Allen]

I read Dom's comments and found them to be so self centred and rude I had to walk away from the computer. Glad I'm not the only one.

You should speak for yourself and not the rest of us, because I don't find working between the two any trouble at all.

[Kim]

Could you people please at least 'try' to stay on topic!! What the hell does any of this have to do with the Sumerian cubit!!!??


Sorry John ..... Thanks for taking the time to share 'your' methods with us mate, that's what our forum is all about and quite clearly your efforts are appreciated by many of us.

As they say folks, if you want a feed just dig in eat the meat and spit out the bones. It all taste pretty good that way and every now and then you'll be surprised by a morsel that's much sweeter than you could have expected.

Cheers

Kim

[greg c]

To which the nymph had replied” “Oh…Sorry, just goes to show.. Hey where’s the nearest Office Works around here? My printers’ all out of papyrus??

Kim[/quote]

[kiwigeo]

It is electronic colonialism. That MS word keeps trying to make me spell labour as labor no matter how many time I tell it I am not a seppo is frustrating enough.

Someone better tell the Labor Party....

[P Bill]

Zealots of all stripes usually suffer from irony deficiency.