Can't get intonation right

I'm trying to intonate my Jackson with a Floyd Rose but it sounds.....well, wrong. I have the 12th fret and harmonic to the same pitch, but 1/3 of the frets (about frets 1-7) are sharp. They aren't just a little sharp, or extremely sharp like a half step, but they are noticeably sharp.

What gives?

Don't intonate to a harmonic, for one. Intonate to open and and fretted 12th.

After that, if it's really sharp at those low frets, your nut might need the slots lowered.

So match the open string with the 12th fret? Shouldn't the harmonic 12th be the same though since it is half the string length? Everywhere I've looked it says to match open to 12th fret, but then to also make sure the 12th harmonic matches the fret.

Intonation is to homogenize the pitch variance from open to fretted notes. The fact that we generally choose the 12th is just a happy medium. There is reasonable debate that, if you are not one to play above the 12th fret, then it makes more sense to intonate at the 9th fret.

Question: How can you say it is half the length of the string if it is not intonated? Until the string is intonated, your 12th fret harmonic isn't half, it's something else. I suppose you'd get there, but using a moving or changing control note would make it tougher.

Once it's intonated, open and 12th fret are the same (because it's half!) so why not use the open string in the first place? :)

I didn't come up with this all by myself, I confess. Most tutorials I've seen do not suggest using harmonics. The only place I ever see that is on Forums. ...You know, those places where the sources are dubious and everyone is an expert? ;)

Here is a good one
http://www.projectguitar.com/tut/intonate.htm

Originally Posted by: Razbo
Question: How can you say it is half the length of the string if it is not intonated? [/QUOTE]

Well I tune all the open strings to pitch, then tune the 12th harmonic to pitch. When they match, I know it is half the length.

[QUOTE=Razbo]I didn't come up with this all by myself, I confess. Most tutorials I've seen do not suggest using harmonics. The only place I ever see that is on Forums. ...You know, those places where the sources are dubious and everyone is an expert? ;)

Here is a good one
http://www.projectguitar.com/tut/intonate.htm

What if you run into a situation where you tune the open string and the 12th fret to the same pitch....but then your 12th harmonic is off (sharp/flat)?

This is one site I was going by:
http://www.icepoint.com/guitar/Setting%20up%20your%20electric%20guitar/

Keeping in mind, I'm aware there are two camps on this. Folks do their own thing; I'm not arguing with you, I'm just happy to discuss something I can reasonably debate! :)

Originally Posted by: hunter1801Well I tune all the open strings to pitch, then tune the 12th harmonic to pitch. When they match, I know it is half the length.[/QUOTE]
BUT, if the string is not intonated, the it's half of something that is not the final length the string string will be. So every intonation adjustment you make actually changes the pitch that 12th harmonic. So, your base note that you are trying to match keeps moving on you.

[QUOTE=hunter1801]
What if you run into a situation where you tune the open string and the 12th fret to the same pitch....but then your 12th harmonic is off (sharp/flat)?

IF you're 12th fret is exactly half, then this is theoretically impossible. However, it's almost never half even when you are done intonating. The only string most likely to be exactly half at the 12th fret is the treble E string. So, this is why you'll get a sharp or flat harmonic.

Look at your saddles. They are staggered, so it's impossible that the 12th fret is exactly half of all of them. (Unless you have one of those bizarre compensated fretboards you linked somewhere else!)

Thus, using a 12th fret harmonic is giving you a misleading tone. You'd have to measure nut to saddle, then find the middle (which could be a quarter inch or so off the 12th), then use that harmonic location.

All this makes the 12th fret harmonic irrelevant except as a ballpark check imo.

Thoughts?

Makes sense, I'll adjust it to the open/fret 12th and see if that helps.

Anyone else want to chime in here? I'm sure there's always more to learn.

Well I learned everything from a certain video on youtube, although its not for Floyd Rose. Its setting up a guitar from scratch, one thats fresh off the line. I did this setup with all my guitars. With one of my guitars I thought it would be permanently screwed up, but I did this setup step-by-step and its flawless now.

http://www.youtube.com/watch?v=xV8kMUB8n4c
http://www.youtube.com/watch?v=-jfakcKV_2A&feature=related

Even though its not for a Floyd Rose, Im sure there are some basics that would still apply and may be able to help ya.

On that video, he recommends intonating using the 12th fret and its harmonic. Guess it's one of those things that everyone has their own way doing.

Originally Posted by: hunter1801On that video, he recommends intonating using the 12th fret and its harmonic. Guess it's one of those things that everyone has their own way doing.

It definitely has 2 camps. When it comes down to opinions, I start analyzing.

Couldn't quite get what he was doing to measure action... Fretting the 12th and measuring the 13th or something?

Couldn't deny his skill, either... Getting intonation dead on pretty much the first try? Usually takes me 3. Then 3 more to check again. :)

Well, I finished up a guitar tonight and had to intonate it. I decided to do at least a partial analysis. I recorded what my tuner was displaying at open, 12th fretted and 12th harmonic at each step. I still tuned open to 12th fretted, but I wanted to see what the harmonic was doing along the way.

What I found was the 12th harmonic is basically 2 cents flat until I get to the B & treble E strings, then it's right on. Therefore, if I intonated to the harmonic, most of my fretted notes would tend on the sharp side.

Maybe that's a more accurate way to have it, I don't know. :p I think I'll have to chart all the fretted notes on each string using both methods and see which, over all, gives me more accurate pitches. (However, given Hunter1801's leading post, I might be ready to postulate a theory on results!)

One thing I did find (as anyone might tuning) is the harmonic note is more stable on the tuner dial. I was using a Seiko tuner I keep out in the workshop, but it usually doesn't waver much.

So, its still inconclusive, but at least it's sort of a control point. And I guess I did half an experiment and made a useless post about it. :embarassed:

I happened to be talking to my Dad earlier, though and he was partial to the harmonic method and wasn't really buying what I was selling. (He is still gigging after almost 70 years.) Therefore I can make one more conclusion: even in the family there can be differing opinions on the method.

I ended up intonation the open to the fretted and it's working fairly well so far. The sharpness is still there but minimized a lot, but that might be less because of the method and more because of the nature of guitars. Not every fret can be perfect so I'm comfortable with how it is now.

Hey gang,
I tune the open string, then do the harmonic at the 12th fret, then note at the 12th fret. Depending on that note I either lengthen, or shorten the distance. All of my guitars are dead on, with all 3 notes. It's a little harder to check that way, but that's what works best for me. One other thing I lay the guitar in my lap, so that all the pressure is off the neck. I've never been able to set the intonation accurately holding the guitar upright.

I do alot of stuff with guitars with the exception of fret work, and the electronics, not what I would like to be with a soldering iron. I had a set up to do for a guy who's wife works with mine, and he wanted really heavy strings on it. The neck on this cheap copy of a strat was not built to take it, really the guitar was not built to take it. Anyway, I put the strings on it like he asked, and tried to set the intonation. It was next to impossible, and I got it as close as I could. I just couldn't pull the saddles far enough back to get it right on the heavier strings.

I know there are alot of players that use heavy guage strings, but they make some modifications to the guitar so it can handle it. You can't just go buy a guitar, and put a heavy guage set of strings on it. Your action is going to be high, and you probably won't be able to set the intonation. If you want to play heavy guage strings, take the guitar to a tech. Have him tell you what you need to do to use heavy guage strings.

The reason I posted this is the problem sounds really similar to what I was going through while trying to set up that guitar. I didn't even charge him to do it, he finally came back a couple of weeks later and asked me to put a set of light guage on. I did, and set the action, then the intonation perfectly for him. It made all the difference in the world on that guitar, but all guitars are different. This may not work on yours, but give it a shot if you happen to be using heavy guage strings.

I have a similar issue with my newly purchased Squier Bullet that I'm slowly working on every day. When I got it a week ago, my fretted 12 would be extremely sharp on strings 6 and 5. I adjusted and tested until the saddle saddle spring was bottomed out but that only help a little. After spending hours researching the topic, I moved on to:

1) Tightening the trem claw so the bridge sits flush on the body (I don't use the trem).

2) Took the stock tuners off, popped the back covers off and tightened and applied blue loctite to the bolt holding the gear in place (they were all loose and the stems were wobbly prior to that). One of them wasn't machined well and wouldn't tighten up flush so I cut a small shim washer out of a 2 liter coke bottle and used that to snug things up.

3) Deburred/lubed the grooves in the nut and string trees.

4) Changed out the factory strings.

The above got it to where it was now just a hair sharp on the fretted 12th, which for a beginner like me is acceptable for the time being and not very noticeable. I then started practicing and taking more GT lessons, but when I started on the open chord lessons, the intonation started bugging me again. Turns out even with the open and fretted 12th pretty close, everything in between is now very sharp. I can deal with just a little, but it's noticeable enough to make me cringe every time I play an open chord.

Originally Posted by: RazboAfter that, if it's really sharp at those low frets, your nut might need the slots lowered.

I now have a Tusq nut and replacement string trees en route to me, so that'll be my next step (thanks for the tip). My files are ready to start messing with the factory nut slot height before I install the Tusq nut to see if that's part of the problem.

I probably spent more time in the past week troubleshooting the intonation issues and making adjustments than I actually practiced. I was going to swap this guitar for another one at the store I got it from, but I'm finding this challenge just as intriguing as learning to play so I'm going to hang on to it for now. I'm looking forward to more suggestions/tips...

Originally Posted by: Ovrdrive
I now have a Tusq nut and replacement string trees en route to me, so that'll be my next step (thanks for the tip). My files are ready to start messing with the factory nut slot height before I install the Tusq nut to see if that's part of the problem.

Great idea to experiment with the factory nut while you have a chance. I recently lowered the slots of my Strat and it made a HUGE difference with open chording. Huge. It unexpectedly improved action as well, and let me get lower at the 12th before I encountered any buzzing. (Although in hindsight, I should have anticipated this bonus effect.)

Since you've clearly done a lot of research, you probably have seen this one, but just in case, my present method is pretty foolproof:

Use a short 3 inch straight edge across the 1st & 2nd frets.
Stack feeler gauges to find distance from straight edge to fingerboard.
Add from .005 - .010 to this distance and stack feelers to match.
Hold the feelers against the nut and file down at an angle to the machine head until you hit the metal of the feeler.

The slots will follow the radius and be quite precisely done, even for clutzes like me! :).