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Intonation - Right at 12, wrong everywhere else?


easilyspooked

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I've been asking sporadic questions to aid in my first partscaster project and am, as ever, eternally grateful for all the advice that abounds on this forum. She's together, she looks amazing, tone is great, feels comfy in the hands, but I'm royally confused about an intonation issue I'm having. Worth stating that I know this is issue is almost certainly my error, that I'm terrible with tolerances, and not at all angry, just hoping to keep working at this guitar until I can make it great.

 

It's a mighty mite strat neck on a GFS tele body, with a GFS xtrem tremelo and bridge set.

 

It has a 25.5" scale length, which I stretched by about 1/8" to intonate the guitar correctly at the low E string.

 

If the low E is in tune when played open, it is in tune when fretted at 12.

 

All the notes in between are horrendously sharp. At first I thought it was just my ear being bad, but then i heard a recording and put a tuner to it, my G is getting very close to a flat G#, it's really out. This is true across all the strings, every fret is sharp.

 

I took the bridge off, filled the holes, and reset it a little nicer, and the issue persists.

 

My problem here is that I have no idea what I've done wrong, if the scale length is right and the guitar sounds the note correctly at the 12th fret, what have I misaligned to make the rest of the frets off? Any clues would be a big help!

 

Thanks again for all your time and knowledge!

Dave

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If the notes in between are sharp it can be several things. Frets aren't crowned properly (doubt that if its a new neck) Neck relief isn't correct, Nut height, String height, string type.

 

If the low E is only 1/8 longer then scale length I suspect you have some major issues there based on string tensions. The High E may be slightly longer then scale length. I usually set it about 1mm longer then scale length. The other saddles can be roughed out too, before you ever plug in a meter.

 

Try setting them this way first. Set the high saddle 1 mm more then scale length, saddle two, 2mm longer, saddle 3=3mm longer saddle 4 = 2mm, saddle 5 = 3mm longer and saddle 6 = 4mm longer. This is ball parking a rough build. You may even want to use 1/16th of an inch instead of millimeters.

 

Set the saddles this way first. Next set the string height, then set the relief, then set the string height, then check your nut height, String height and relief.

 

THEN, get down to fine tuning your intonation. Start with the last fret using a good chromatic tuner. Match the open string to the last frets. DONT try and tweak it all in at once. Do 1/4 turn on the saddle screws at a time. If all strings are sharp, turn all the saddles 1/4 turn, then go back check relief and string height. Be sure to push the strings down at the bridge too. Moving saddles can leave an arch in the string at the saddle which throws the intonation.

 

After checking the open and last frets see if its closer. Repeat the operation till one of the strings, doesn't matter which is fairly in tune at the open and last frets. That will be your hinge point for getting your other strings intonated.

 

If its your low string, check the last and compare it to the 12th. Tweak that one saddle a tad and see if you can get both in. We're talking about 1/8 or less turns now. Then work your way across the strings trying to do the same. On most guitars you will have the same kind of saddle spacing. The second is back by one, the third is back by two the 4th matches the 2nd, the 5th is back by 2 and the 6th is back by three.

 

The actual measurements may have the second saddle a little closer to the first and the 5th a little closer to the 4th. Fender does this staggered saddle spacing based on the strings themselves roughing it out. You set the 2nd saddle back from the 1st by the width of the 2nd string (.11) . The third saddle is set back from the 2nd the width of the third string (.017), The 4th matches the 2nd, the 5th is back by the width of the 5th string (.32 on a set of 9/46 strings) and the low E is back towards the tail by the width of the low E string (.046)

 

I find this spacing inadequate for most guitars especially ones with high frets and light strings. It may work with a heavy set of string gauges, but I find the millimeter trick good enough to get me there. Heavy string you probably need 1/16ths.

 

The idea here is to get the proper string length close first because this dramatically changes the stress on the neck which influences the relief. Get the relief and height right before attempting to intonate, otherwise you'll be jacking around with the thing never getting the intonation or tone right.

 

There are other ways of doing this but try this method first. Be sure to measure the relief with a straight edge and feeler gauges. Don't trust your eyes. You should be able to get a .009 or .010 Feeler gauges between the 5~7th frets with the guitar tuned to pitch "in the upright sitting position" not with a guitar laying on its back.

 

Test your harmonics at the 5th, 7th and 12th 17th and 19th frets against the fretted notes. The 7th and 19th should be sharp in comparison to the open strings. This is normal, but the harmonic and fretted notes should have the same amount of variance between them. In other words, if the 7th harmonic is sharp by 5 cents compared to the open strings, the fretted note should also be sharp by that same 5 cents

 

The harmonics at the 5th, 12th and 17th should match the fretted notes and the open strings should also be in tune.

 

Try these things out and see if it gets better, I have other tricks if these don't quite get you there.

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WRGKMC once again, Thank You so much for your expertise, my bass player came over and joined me in the shop to experiment with this, we followed your roadmap, not only is the action now amazing, but by being methodical and starting off correctly we were able to dial in the intonation very easily, really, really appreciate it!

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That's great news, Glad I was able to help.

 

Some of those techniques can be found here. http://www.fender.com/support/articles/stratocaster-setup-guide/

 

You can find others goggling around. Its good to read as many different approaches to setups as you can to get a good vision on how to approach these things.

 

One other I was talking about the other day on another thread was using an electronic keyboard or pitch generator instead of a tuner.

You pipe the sound into the same amp you're playing through then wedge the key down on the keyboard playing a note as close to a sine wave as you have. A pure organ note works very good.

 

Then you work your way through one string at a time, Set it for E and tune you high and low E to the Keyboard, then compare octaves. If you hear any string beating between the tone and the string you know the intonation is off a tad.

 

You also want to check all the other E notes on the neck you can find on the other strings. Do this for your A, D, G and B strings too working yourself across from low to high strings. Also compare matching octaves, the two E strings working up the neck fret by fret, 6th and 4th string octaves etc.

 

I find doing the ear check helps eliminate things the tuner cant hear like strings twanging sharp and tonal differences. A tuner will attempt to tune into the fundamental tone a string produces. Unfortunately that is far from being a true sine wave. If you've ever seen a guitar note on a scope its full of overtone humps and the north and south going waveforms can be shaped differently and anything but round.

 

The meter takes the best guess at what's close and can be accurate once a guitar is sett up properly. When a guitar is out of specs they don't do so hot for doing setups or helping you guess how far out the settings actually are. A strobe scope is better because it moves at varying speeds, but even they can be tricked. You ears on the other hand can be more accurate because they hear, tone and pitch, and hear oddities a meter completely ignores. Setting up a guitar properly by ear has become a lost art which is a shame because it is the true test of how well a musician or a Luthier actually hears tones.

 

In the days before tuners, you weren't even considered to be a good musician till you could tune accurately by ear. Don't know what changed that but instead of being a tool that aids you under noisy conditions, guys trust them like religion and they completely ignore what their ears are telling them. Back in my day you had to tune by ear because every album you practiced too was off at least 1/4 semitone or even more. Then you get the imported albums where their turntables ran at 50 hz would be at a different pitch with a properly tuned guitar and you'd get guys not tuned to proper pitch playing songs with transposed chords.

 

Even music books would give you chords transposed because they didn't know they would do things like speed up tape decks to make the music sound more up tempo and lively. If course this would drive the musical pitch up too. Today most have stuck with 440 standard tuning, but there's still plenty of recordings using studio tricks to change pitch and trick guitarists attempting to copy the music to get it wrong. Cant trick a good ear if you have it developed though.

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Setting the neck and bridge is tough sometimes with builds that are from scratch. I suggest setting the bridge so all the saddles are in the middle of their adjustment range. Then measure 25.5" or whatever the scale for the neck is and place the bridge there. The intonation should be able to be worked out from there. That much already makes sense.

 

Now I have found the largest contributor to intonation issues is action height. The big trick to getting low action is having the frets leveled and crowned while the neck is perfectly straight. A new neck made by a reputable manufacturer should be pretty spot on. Setting the relief is very important to low action. I set it so it's as flat as possible and then give it the ever so slight relief. Now nut height and bridge height can be set. You want the nut to be set as low as can be without buzzing while playing hard on open strings. Any more than the strings thickness above the fret is probably too high. The bridge should set to get the string as low as possible without excessive buzzing or fret outs on bends. The rule of thumb is that the string should not be any higher than the thickness of a quarter at the 12th fret. I shoot for lower. Heavier players that like sounds free of buzz will require higher height and bluesier guys with a little more touch usually aim for lower settings allowing a little buzz.

 

The height of the action will severely effect intonation. the higher the string the more off it will be at any position on the neck only being right at the fret that intonation was set for. How close to the pickup the strings can also effect intonation. To close and it will actually pull on the string enough to make it go sharp.

 

One of my experimental guitars is set with action so low it will pretty much play itself. I have the relief set with a tiny amount of backbow even. On bends it will straighten out. I went so far as even making a compensated nut. The guitar is in nearly perfect intonation at every position on the neck. The low action and the more refined intonation settings makes for a guitar that is so easy to play you only have to think of the note and it will play it for you.

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Setting the neck and bridge is tough sometimes with builds that are from scratch. I suggest setting the bridge so all the saddles are in the middle of their adjustment range. Then measure 25.5" or whatever the scale for the neck is and place the bridge there. The intonation should be able to be worked out from there. That much already makes sense.

 

Don't know about that statement. I've never seen a guitar that has strings set shorter than scale length. If anything the high E might be ok at Scale length, but all other strings are longer no matter how high the action is set. Setting all saddles in the center may cause you to run out of room adjusting the strings longer as they get thicker so I'd advise modifying that statement especially for bridges that have very little saddle adjustment. I'd set the high E towards the neck side with just a little clearance and then set that for your high side placement at scale length. The low E usually winds up being around 5/8 or more longer then scale length so I'd make sure that saddle can be adjusted towards the tail by at least that much.

 

Now I have found the largest contributor to intonation issues is action height. The big trick to getting low action is having the frets leveled and crowned while the neck is perfectly straight. A new neck made by a reputable manufacturer should be pretty spot on. Setting the relief is very important to low action. I set it so it's as flat as possible and then give it the ever so slight relief. Now nut height and bridge height can be set. You want the nut to be set as low as can be without buzzing while playing hard on open strings. Any more than the strings thickness above the fret is probably too high. The bridge should set to get the string as low as possible without excessive buzzing or fret outs on bends. The rule of thumb is that the string should not be any higher than the thickness of a quarter at the 12th fret. I shoot for lower. Heavier players that like sounds free of buzz will require higher height and bluesier guys with a little more touch usually aim for lower settings allowing a little buzz.

 

The height of the action will severely effect intonation. the higher the string the more off it will be at any position on the neck only being right at the fret that intonation was set for. How close to the pickup the strings can also effect intonation. To close and it will actually pull on the string enough to make it go sharp.

 

One of my experimental guitars is set with action so low it will pretty much play itself. I have the relief set with a tiny amount of backbow even. On bends it will straighten out. I went so far as even making a compensated nut. The guitar is in nearly perfect intonation at every position on the neck. The low action and the more refined intonation settings makes for a guitar that is so easy to play you only have to think of the note and it will play it for you.

 

You never mentioned what you consider low action to be. To one person, factory specs of 3/64th's on the high E and 5/64ths on the low E is about as low as you can get on a new guitar with perfect frets. Anything lower usually has bad results especially on guitars with lower radius. Low radius necks will fret out bending strings above the 12th so higher actions are necessary to get minimum playability. Acoustic guitars often use 5/64 and 7/64 as a minimum standard. This is usually high enough to prevent fret buzz and provide clear acoustic notes.

 

Height shouldn't have that much effect until your start getting pretty high and using light strings. You can set an electric up like an acoustic with heavy strings and still have good action and intonation so its more about how string your fingers are holding down strings.

 

The big problem with low action is the way strings flex when depressed. The actual flex of the string when being depressed is what puts many of the frets in tune. Manufacturers usually target the average factory string height and with really low action you may not get enough flex in strings to bring them up to the proper pitch in the center of the neck. Nut height also makes a huge difference with all the adjustments.

 

The lowest I will set a nut and avoid issues is to make sure the strings clear the first fret when the second or third fret is held down. Even with a zero fret guitar I try to leave that first fret higher then the rest just so there's some clearance. I had a buddy bring me two guitars where the nut was lower then the first fret and wound up having the bridge height much higher then needed to get the lower frets to clear. Raising the nut allowed me to lower the bridge and he no longer has sharp notes above the 12th fret with the intonation properly set.

 

The other big deal is flat frets. If you have flat frets its unlikely you can raise the action very high without causing string buzz and intonation issues because the break away angle is at the edge closes to the bridge. With crowned frets, the break away angle at the fret will vary with string height. The higher the string angle the close to the nut side of the fret the string will ride, but never more then the center of the fret with low action. .

 

Lastly, Guitars do have tempered tuning and cannot produce perfect pitches along the entire neck no matter what you do with height intonation of relief. The best you can hope for is having all frets slightly out of pitch to get the entire instrument to sound in tune then dial up amp tones that hide most of the slight variations that occur when you have straight frets. Even then you often have to compensate tuning the instrument when playing in different keys.

Compensated nuts don't work well either. They help a little at the first few frets but the underlying issue is still there. The only way those interval variations can be fixed and its by using a guitar with a compensated fretboard that provides true temperament. http://www.truetemperament.com/ These can work for someone who plays acoustic or doesn't bend strings but they'd be pretty useless for someone who bends strings.

 

You also have the problem playing along to other guitars that are not true temperament and you can wind up having string beating occur between the two instruments. I found this out when I tried several Earvana nuts on guitars for a few years. They weren't bad is you played with others that had the same system, but playing a normal guitar along with one that has a compensated nut, was enough to drive my ears nuts. The strings themselves aren't designed for them either so you'd wind up having some strings that sounded darker then others.

 

So we do have to realize we play imperfect instruments when we set them up and try and target the adjustments that produce the least amount of issues both for the ears and the hands. If you're lucky you can usually fake people into thinking the notes are all properly in pitch, and if you leave a little neck and string flex you can pull on the strings or push on a neck to vary the pitch a small amount to get those notes in.

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I should have been a little more specific about bridge placement. The scale length will pertain to the high E. The low E is usually a little further away. I have 11 electric guitars and they all are within 1/4" or less of adjustment from high E to Low E on the saddles. Most bridges have about a 1/2" adjustment range from end to end. This should be enough. If you are really concerned error to the long side. If the scale length is supposed to be 24.75" on the high E the set the bridge so that the saddle when adjusted further out sits at 24.75" that way the low E saddle can be pulled back further than 1/4". I have never seen a guitar that has a 5/8" variation on the low E from scale length except in extended range instruments or a standard guitar set up with ridiculously large strings. That being said, the guitar I have with the compensated nut, the saddles are only about 1/8" apart from high E to low E. So even if you are slightly off on the placement of the bridge, a compensated nut will fix that. Not that doing that is a goal. Look up compensated nut and see the technique on how to get one or make one. It's not that hard really. If you can build a guitar, you can make a compensated nut. The setting of the bridge is basic. What is the scale length. Where is the center of the saddles adjustment range ( keeping in mind how much adjustment there is ) and error to the long side if needed so you can pull them back further and place the bridge so the string break on the high E is right at your scale length.

 

I did say " as low as possible without excessive buzzing and fret outs. " That is obviously too low. The nut height I think I was pretty clear. Just about the thickness of the strings over the fret ( meaning first fret ). I would leave a slightly larger margin for the smaller strings. You could also set the height so that it is uniform across the nut so that each string can just fit the D string under it at the first fret. The typical D string is usually 24-26 gauge. That is .024-.026 of an inch. This will ball park you at least. Most players like the low E around .020" and the high E at about .010". Obviously the strings will graduate as you go from low to high E. For reference most places will rough the nut in at .030" and cut down from there to players taste. Most nuts that are pre made will already have the graduation built in. All you have to do is file the nut base flat so that you get the height you want at the high and low E.

 

No the guitar is not a perfect instrument and the intonation will only ever be truly spot on at one or two spots on the neck. I think that the compensated nut is the better of two evils. The true temperament neck is probably out of the question for all but the most expensive builds. Leaving the compensated nut next in line. It's pretty easy. When done the guitar will be in better intonation over the entire length than that of a standard nut/bridge setup. If you really wanted to go to extremes then a multi scale neck is the best all around. The true temperament neck is probably not possible for the average or even advanced luthier. It is something that can probably only be done by the best builders ( with really good math skills ) and would still require a machine to cut the fret line. The Buzz Feiten tuning system is basically a compensated nut with a weird tuning regimen. Basically you pay $139 dollars for a nut and the information on how to set the saddles and then tune the guitar. A fully compensated nut is meant to fix the deficiencies in the lower octaves from intonating at higher than the 12th fret. This includes getting the G string closer to pitch when fretted above the 5th fret. The Earvana system is about $40 and there is no special tuning regimen. The short fall of the Earvana is that it's not 100% pitched to your guitar. A home made compensated nut can be made for under $30 using two nuts ( or one double thick one ) and about an hour of your time and will be closer than the other two. The challenge is that you need to be handy with a dremel.

 

I still think that action is a huge factor in intonation. The longer distance you have to push the string down onto the fret, the more the string will be pitched sharp as you actually acquire fretting. Flat frets as far as I can tell are not a deal breaker. The break angle is still the same ( in relation to action height ), but buzzing may be more prominent? There is nothing to gain from high action. To me high action is where any string is higher than the thickness of a quarter.

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