Intonation again.

Intonation, Compensation, Frustration
Zen
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Re: Intonation again.

Post by Zen »

B. Howard wrote:I do not use the open note. I use the 12th fret harmonic and the fretted note at the 12th. Here I am balancing the half string. Yes you need to adjust tension to bring the string back to pitch but you will reach a balance point where the 1st partial and the fretted half string ring the same pitch. I am also tuning the string by the harmonic and not the open note when i do this. In theory using the open note will work but I feel I get more accurate settings using the partial. By adjusting the speaking length, when you fret the 12 the distance is longer than scale would dictate there by flattening the pitch to compensate for the slight increase in tension created when the note is fretted which is what causes it to go sharp.

This by the way is not the only way to intonate a guitar. In certain instances I will compare the notes fretted at the 5th to the 17th and make them exactly one octave apart.

Brian , I know you are most probably correct in what you say--as you are on most subjects we discuss here--but I'm not sure the average guy trying to set up his guitar or even the average repair guy will find themselves tuning the harmonic of the note or maybe thats just me looking for the easy options lol
But. maybe I am seeing your method as being a lot more complex than it actually is, and if so please forgive me for being so negative . Its just that I get excited any time the needle on my tuner actually goes to green when I fret the 12th and I dont have too much tweaking to do.... the lazy mans method I guess!! Thanks for all your great advise on this forum by the way.
Rusty
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nehsgolfer
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Re: Intonation again.

Post by nehsgolfer »

My original statement is still true-I don't understand intonation procedures!!
B. Howard
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Re: Intonation again.

Post by B. Howard »

Ok, in a nut shell, this is what we are doing when we set our intonation. The open string will play a certain note determined by its length and tension (we will leave string gauge and such out of this as it does not pertain directly to the process). The fret spaces create divisions that will create successively higher notes from that based on the pure mathematics of the string length, and make the assumption that tension will be a constant. The problem is that when you fret any note, you stretch the string as you press it down. This does not affect the strings actual length enough to make a real difference but it does cause the tension of the string to increase. This increase in tension will cause that fretted note to ring sharp. So we must therefore increase the speaking length so that the fretted note rings true to pitch. By setting out intonation we are looking to balance out this error that is created by the string stretching to it's least possible amount. Perfect intonation over the entire fret board is never truly attainable. We are averaging out the errors.The higher the action, the more compensation will be needed as the string is stretched farther when fretted.
You never know what you are capable of until you actually try....

Brian Howard
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Zen
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Re: Intonation again.

Post by Zen »

Thanks again Brian, Heres a scenario I find frequently on acoustics. I tune the high E string and its in tune in the open position--but its sharp at the 12th so I need to lengthen the string ? Easy on an electric- not so easy on an acoustic.. As John said, one way of doing this on an acoustic is file the front of the saddle . On some saddles there may not be much material to file and you will be left with a sharp ridge if you file too much away. But, is there an alternative way?
And then another question, if the 12th note is flat instead of sharp do you file the back of the saddle or is that a silly suggestion?

And, am I correct in thinking that everyone wants a low, low, action these days, no matter what.. lol

Rusty
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B. Howard
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Re: Intonation again.

Post by B. Howard »

Yes electrics are easier to set up. And yes if the fretted note is flat you need to shorten the speaking length. Filing the back of the saddle may or may not work. That is because on an acoustic so much is dependent on the bridge and how it was made and how it was set. There are ways to do it. If the saddle is 3/32 you can rout out the channel for a wider bone and shift the slot a bit to improve things. I have seen bone extensions glued to the front or back of a saddle to increase width as well. this is all why it is so important to get the saddle slot cut correctly into the bridge and to get the bridge positioned and glued on as precisely as possible.

There are a lot of other variables in play as well such as the gauge of the strings and even the brand. Sometimes a different brand of strings will intonate better because of different tensile strength of the steel, core wire size and shape on the wound strings. Even the players left hand attack will have an impact on intonation. Gravity will change things also. If you set your intonation with the guitar on the bench when you put it into the playing position it will be off because of gravity. As such I always work on mine in the playing position. Oh and lets not forget RH when we are dealing with acoustic guitars.......

Action height has a major effect and to some extent so does neck relief. A lot of folks simply think they want their action as low as possible but in reality few actually need or really want it that way. Bluegrassers and heavy strummers often need action that is fairly high by most standards to keep from buzzing. Finngerstylists will generally prefer things rather low and most average players will quite happy in the middle. Part of this job is figuring out what the player actually needs and delivering it, as long as the guitar plays well for them they will not ask questions about the exact specs it was set up at.

If you are noticing on your builds that you are consistently sharp on your fretted high e you may want to move your bridges a bit farther down the body. If it is just mainly the higher strings maybe you need to change your slot angle. It took me a few guitars to get these things dialed in for myself. On older guitars as they age and move toward needing a neck set, the action will grow higher and the intonation will drift and want a longer speaking length. When the neck is done it will be back to where it started.
You never know what you are capable of until you actually try....

Brian Howard
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ruby@magpage.com
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Re: Intonation again.

Post by ruby@magpage.com »

At the Woodstock Guitar Show 2 weeks ago, there was a great panel of six builders/repair guys and they were asked random interesting questions. One of them was Matt Umanov

http://umanovguitars.com/

He said by 1970 he had a sign above the repair station that read (IIRC) "if you want very low action and no buzzing, please leave now"

Ed MInch
Ed M
Zen
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Re: Intonation again.

Post by Zen »

ruby@magpage.com wrote:At the Woodstock Guitar Show 2 weeks ago, there was a great panel of six builders/repair guys and they were asked random interesting questions. One of them was Matt Umanov

http://umanovguitars.com/

He said by 1970 he had a sign above the repair station that read (IIRC) "if you want very low action and no buzzing, please leave now"

Ed MInch


Love that quote !!! Its exactly how I feel at times .
RUSTY
Dan Bombliss
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Re: Intonation again.

Post by Dan Bombliss »

Zen,

What you need to know about some cheap acoustics, is that when they are built improperly and the saddle slot is in the wrong position, you will NEVER intonate it. Unless of course, you plug the hole and reroute the saddle where it should go.

As far as this shaping the saddle goes to get the peak where it needs to go, take a very light gauge "e" string (high e) and use it as a peak. If you are sharp, just to know if you can possibly fix anything, place the cut off of the "e" string under the string in question that needs to be lengthened. Place it under the string as FAR BACK as it can possibly go on the saddle. Tune it to pitch, and check the harmonic and/or open tuning the with fretted. If it is still sharp, this guitar is a lost cause to dial in. That will be the closest you can get (carved all the way back) but it may be closer than not, so is still better than not doing anything.

-Dan
tippie53
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Re: Intonation again.

Post by tippie53 »

Good point
the guitar may have the saddle out of position. Measure the nut to the 12th fret add about .100 inch and that is where the saddle should be following the line on the 1st high E string ad 1/8 in to the and that is the point for the bass e.
You have to look at intonation at the open and the 12th fret harmonic. When setting up a guitar you have to know how to adjust the saddle. You can also compensate the nut .
This was a discussion I did at ASIA symposium with Evan Gluck. Another one that explains the saddle.

NOTE
if the saddle is out of position , there isn't much you can do other than move the saddle and get it where it needs to be.

http://www.youtube.com/watch?v=o8KXlOqva-0

http://www.youtube.com/watch?v=Gg-0iDXx4jc
John Hall
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president of Association of Stringed Instrument Artisans
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Zen
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Re: Intonation again.

Post by Zen »

Thanks to John and Dan and everyone else who gave advise, and for that insight into intonation. Now it makes sense to me at last.

Rusty
RUSTY
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