Intonation on acoustic guitar--light to medium strings

[feyshay]

Since about the time of the switch (I think) from light to medium strings on my acoustic guitar, I have noticed what appears to be an intonation problem on my Martin guitar.
I'll tune the open bass E string, but when fretting at the 5th or 7th frets, for example, will get a note that sounds a bit out of key. (It seems to be a higher when using my Strobotuner--I get a blur of a strobe. The tuning difference is noticeable.).
Should I just switch back to light strings? Any fixes that don't require a chisel?

[jwl]

First, make sure the neck is properly positioned (ie, not bowed).

If it is, and if the intonation is out, you'll probably have to carve a new saddle for the bridge, paying careful attention to where the strings touch it, as well as getting the string height down, while maintaining a perfectly flat bottom so it seats right and you don't lose tonality.

Unless you want to dive in and do it yourself, I'd take it to a good, experienced acoustic guitar luthier in your area to do it. Shouldn't be too expensive (under $100)....

[travisbrown]

Your action will have changed when you put on heavier strings. This will affect your intonation. If it's a permanent change, you should look at at least adjusting the trussrod to take the action back to where it was previously. The intonation should get better, but you might get some buzzes. If this is the case, you need a slight setup to compensate.

I run into this all the time. When I'm using drop tunings, I play with 59-15s; when I'm in standard tuning, I play with 56-13. There's a lot of futzing to keep the intonation passable.

[Acoustic Cloud]

There is no way to fix, or even address intonation on an acoustic. Besides buying or making a compensating bridge bone, it is what it is. If your notes sound out of tune, the slight difference in offsetting a few angles on the bridge saddle may not even make a difference...the bridge bone is only so thick, therefore you can only offset so far. (If more is needed)

Truss rod adjustment only affects the action if it is way too straight, or way too bowed. In most cases, going up or down one guage wont need too much adjustment, if any at all.

If you want to stay with the current new gauge strings, you might try another set, before you go back. Once in a while, strings will have their own issues because of a manufacturing tolerance screw up. Its pretty rare, but I have seen it before.

Most times, there is a problem when people go from heavier, to lighter gauges, and they are used to fretting too hard, pushing some notes sharp.

[travisbrown]

Originally Posted by Acoustic Cloud

There is no way to fix, or even address intonation on an acoustic.

That's not exactly true. Action changes from the camber of the neck do indeed change scale length and therefore intonation. The more bow, the shorter the scale (shortest distance between two points being a straight line and all)

Up or down one gauge is not going to make that much difference in a stiff-necked and heavily braced guitar, true. But it does make a difference, sometimes drastic, on lighter necked or ladder braced guitars. As you increase tension getting heavier strings up to pitch, you pull back on the neck and up on the soundboard (unless you have a trapeze bridge).

There is lots you can do to fix intonation on an acoustic. You are more limited in the ease with which it is done compared to electrics with adjustable bridges and all.

Here are some intonation fixes from lightest to most severe.

1. Increasing or decreasing scale length by inducing or decreasing bow in the neck. This of course, affects action, which can be compensated for somewhat in item two.
2. bridge and nut action - the further you have to push the string to fret it, the more you increase the tension and raise the pitch.
3. Saddle shaping/compensation
4. Fret crowning or replacement (as frets wear down, they the contact point changes.
5. Compensated nut. <- all acoustics should have a compensated nut, in my opinion.
6. Saddle repositioning, split saddles
7. New neck and fanned frets.
8. Start playing oud.

Any good repair luthier will be able to quickly assess what combination of the above will give your guitar the best intonation.

Here's where you can get lots of free expert advice: MIMF forum: Guitar Building: Acoustic Guitar Building, Electric Guitar Making, Archtop Guitar Building, Guitar Repair, Violin Making, Dulcimer Making, Mandolin Building, Banjo Building, Drum Making!

[lofi]

i couldnt agree more with travisbrown

i would add that ALL guitars should have compensated nut and somewhat fanned frets. graphite superstrong necks also...it soooo much better.

also all drummers should learn how to tunes drums...

ok now im dreaming and its off topic...

back to mix......

[feyshay]

Thanks for the tips. Some of what you say is beyond my understanding and mechanical abilities, but at least it is a start for more research.

[travisbrown]

JWL gives good advice: A trip to a qualified guitar tech will prove wonders and doesn't have to cost a fortune if the guitar's in good shape.

[Acoustic Cloud]

Originally Posted by travisbrown

That's not exactly true. Action changes from the camber of the neck do indeed change scale length and therefore intonation. The more bow, the shorter the scale (shortest distance between two points being a straight line and all)

Up or down one gauge is not going to make that much difference in a stiff-necked and heavily braced guitar, true. But it does make a difference, sometimes drastic, on lighter necked or ladder braced guitars. As you increase tension getting heavier strings up to pitch, you pull back on the neck and up on the soundboard (unless you have a trapeze bridge).

There is lots you can do to fix intonation on an acoustic. You are more limited in the ease with which it is done compared to electrics with adjustable bridges and all.

Here are some intonation fixes from lightest to most severe.

1. Increasing or decreasing scale length by inducing or decreasing bow in the neck. This of course, affects action, which can be compensated for somewhat in item two.
2. bridge and nut action - the further you have to push the string to fret it, the more you increase the tension and raise the pitch.
3. Saddle shaping/compensation
4. Fret crowning or replacement (as frets wear down, they the contact point changes.
5. Compensated nut. <- all acoustics should have a compensated nut, in my opinion.
6. Saddle repositioning, split saddles
7. New neck and fanned frets.
8. Start playing oud.

Any good repair luthier will be able to quickly assess what combination of the above will give your guitar the best intonation.

Ok

The adjustment of amount of bow in the neck (via trussrod) of any guitar, has nothing to do, (or ever has) with action adjustment. Like I said, the action may be affected by this if it is severe. the strings vibrate in an ecliptical (sp?) pattern,like a jumprope. The neck has to some degree, equal image this in order for fretted notes up AND down the neck to not "fret out". This is why there is a truss rod. I have seen many necks retain proper bow, but the whole neck as a unit gets pulled up, due to string tension, cheap guitar, strings too heavy, etc etc. Thus leaving the guitar totally unplayable. Still, probably not his problem.

Nut "height" I assumed this was already ok, maybe its not. But this would not have changed with string change, especially heavier ones. Unless the nut slots are way to small, rendering the strings,like sitting on top of them.???

Fret contacts with worn frets are still totally minutely minimal in fretted intonation length. The buzzing would drive someone nuts (no pun intended) before any intonation problemswould be evident.

Saddle repositioning, new bridge, splitting the saddles, new necks, are all symptoms of fixes for guitars that were never rightly in tune in the first place, IMO..

[u b k]

there's also a more "occam's razor" explanation for this problem: because of unfamiliarity with heavier strings, the player is pressing harder than necessary to fret the notes and thus is increasing their pitch.

it's amazing how *little* force is required to properly fret a note. i mean no disrespect to the OP or his playing abilities, i'm just exploring all the options.


gregoire
del
ubk
.

[Acoustic Cloud]

Originally Posted by u b k

there's also a more "occam's razor" explanation for this problem: because of unfamiliarity with heavier strings, the player is pressing harder than necessary to fret the notes and thus is increasing their pitch.

it's amazing how *little* force is required to properly fret a note. i mean no disrespect to the OP or his playing abilities, i'm just exploring all the options.


gregoire
del
ubk
.

But, he went to heavier strings, not lighter.

Sorry if I sound like a donkey about this, but Im no Mickey Mouse in the department of playing-teaching and repairing, like I am at recording!

Its a bit more my "forte" "forty" "for-tea" "foetee"!!

[travisbrown]

Originally Posted by Acoustic Cloud

The adjustment of amount of bow in the neck (via trussrod) of any guitar, has nothing to do, (or ever has) with action adjustment. Like I said, the action may be affected by this if it is severe. the strings vibrate in an ecliptical (sp?) pattern,like a jumprope. The neck has to some degree, equal image this in order for fretted notes up AND down the neck to not "fret out". This is why there is a truss rod. I have seen many necks retain proper bow, but the whole neck as a unit gets pulled up, due to string tension, cheap guitar, strings too heavy, etc etc. Thus leaving the guitar totally unplayable. Still, probably not his problem.

Nut "height" I assumed this was already ok, maybe its not. But this would not have changed with string change, especially heavier ones. Unless the nut slots are way to small, rendering the strings,like sitting on top of them.???

Fret contacts with worn frets are still totally minutely minimal in fretted intonation length. The buzzing would drive someone nuts (no pun intended) before any intonation problemswould be evident.

So if you introduce more bow in the neck, the action isn't higher around the middle of the neck? I'm not saying it's a proper fix for action; I'm saying that if you put on heavier strings on a lightly braced guitar, the increase in tensile load between the nut and bridge induces "lift" at both ends and increases the bow. I certainly see it between 13s and 15s on my dreadnought. When I switch gauges, I give an 1/8th of a turn on the truss rod to compensate.

I wasn't listing all the things wrong with the OP's guitar; likely it just needs a proper setup for the gauge of strings he is using: tiny trussrod adjustment and maybe slight saddle reshaping. I havent' looked at it, and suggested that if a slight trussrod adjustment doesn't remedy it, that a local guitar tech would likely suss out quickly the issue and fix.

I was listing fixes in order of severity that can by themselves or in combination better the intonation on an acoustic.

Originally Posted by Acoustic Cloud

Saddle repositioning, new bridge, splitting the saddles, new necks, are all symptoms of fixes for guitars that were never rightly in tune in the first place, IMO..

Indeed this is true. These are extreme remedies. But it is sometimes needed, and not just on cheap guitars. I've seen bridges in the wrong spot on really expensive guitars made by renowned luthiers.

And almost every good guitar will need a neck reset sometime in its life. Not so much with the bolt-on necks like Taylors and Collings, but certainly with dovetail and mortice/tenon joints.

Like you, lutherie is more my forte than recording. (I'm not working on the aforementioned expensive-type guitars, though, lest it seem like I was inferring so. I have a 1908 Gibson F4 that I don't trust myself to work on.)

[feyshay]

I made sure to use a capo to check this intonation out and made sure the capo was placed carefully (without bending the strings).
I'm sure it is not my playing that is causing it.
I took a closer look at the guitar last night and do see some bowing. Bowing--I believe induced by the heavier strings. I believe the action is a little higher than it used to be. I also believe that there is not significant fret wear to account for the intonation problem.
My thought is that I'd like to stay with medium strings, since I have built up the strength to play it properly. I could switch back to light strings, but my thought is that the bowing has already been done and will likely not be undone by light string placement.
What I'm going to do (with your approval) is take the simple step of loosening the strings and making slight truss rod adjustments (marking the original position) and see if I can make do with just a truss rod adjustment to lessen the bowing.
If that doesn't work, I'll take it to a lutheir. Does that sound reasonable? Any further advice?

[travisbrown]

The bowing isn't permanent - that's what your truss rod is for. Likely the bow would decrease if you went back to lighter strings. A slight adjustment of your truss rod will fix it.

I don't loosen my strings when I am making minor truss adjustments, but I have a truss wrench for my guitars that doesn't require getting my hand in the soundhole.

What do you mean that you are using a capo to check intonation? Capos just transpose intonation problems. I always retune slightly when I put a capo on to compensate.

Don't be too scared to adjust your trussrod - it's only kinky the first time.

[feyshay]

When I meant I use a capo, this is what I meant. My understanding of intonation problem is that on some frets you may not be getting the note you want to be getting even though you might be getting it on other frets or on the open string.

In order to verify that I was having an intonation problem, I would plug into Strobotuner and tune the open string. Then I would play at various frets and see how far off was intonation. To rule out that I was bending strings, I also used a capo in order to check tuning at certain frets.

I think I'll continue to shoot for the thicker strings on the Martin and make the necessary adjustments. I imagine I would be making a minor adjustment, checking intonation, making more adjustments, etc.
Thanks for the help.

[Sounds Great]

I took my Takamine 12 string to a pro many years ago with such problems. He made a new saddle and tweaked it up nice. I think it might have been about 100 or 150 bucks. Definitely worth it.

[Acoustic Cloud]

Originally Posted by feyshay

I made sure to use a capo to check this intonation out and made sure the capo was placed carefully (without bending the strings).
I'm sure it is not my playing that is causing it.
I took a closer look at the guitar last night and do see some bowing. Bowing--I believe induced by the heavier strings. I believe the action is a little higher than it used to be. I also believe that there is not significant fret wear to account for the intonation problem.
My thought is that I'd like to stay with medium strings, since I have built up the strength to play it properly. I could switch back to light strings, but my thought is that the bowing has already been done and will likely not be undone by light string placement.
What I'm going to do (with your approval) is take the simple step of loosening the strings and making slight truss rod adjustments (marking the original position) and see if I can make do with just a truss rod adjustment to lessen the bowing.
If that doesn't work, I'll take it to a lutheir. Does that sound reasonable? Any further advice?

Try this:

If you push the low E down at the first fret, and at the 14th fret with your thumb on the right hand (15 or 16 for electrics, because the relief or straightening does nothing for acoustics past 14th, because of the heel and fretboard tongue) then tap down at the 7-8th fret on the string. You should have a gap of maybe 2 business cards or less between the fret and the string. If its touching the 7th fret, you need to loosen. If its crazy, like an 1/8th of an inch, you need to tighten the truss rod.

The string is used as a straight edge here, telling you waht the bow is like. Some necks are even back-bowed, and this is hard to fix, but I wont go there now.

Try that, and see whats up. I would not take the tension off the strings when doing this. Its like balancing a rim with no tire on it. If you increase or decrease neck tension, the affect does not happen immediately. It may take a day or so for it to set in completely.

[travisbrown]

Originally Posted by Acoustic Cloud

Try this:

If you push the low E down at the first fret, and at the 14th fret with your thumb on the right hand (15 or 16 for electrics, because the relief or straightening does nothing for acoustics past 14th, because of the heel and fretboard tongue) then tap down at the 7-8th fret on the string. You should have a gap of maybe 2 business cards or less between the fret and the string. If its touching the 7th fret, you need to loosen. If its crazy, like an 1/8th of an inch, you need to tighten the truss rod.

The string is used as a straight edge here, telling you waht the bow is like. Some necks are even back-bowed, and this is hard to fix, but I wont go there now.

Try that, and see whats up. I would not take the tension off the strings when doing this. Its like balancing a rim with no tire on it. If you increase or decrease neck tension, the affect does not happen immediately. It may take a day or so for it to set in completely.

[peeder]

Echoing ubk's advice, a capo is really hard to get intonation right with. Don't pay any attention to your capo results...and when using a capo, make sure you put it on and off a few times, pretty close behind the fret you are working, so that the strings aren't bent by the capo.

The way you check intonation is by playing the 12th fret and the harmonic at that fret (no capo on nowhere!!!) and seeing if they match. You have to get your truss rod adjusted and I highly recommend seeing a guitar tech because it's easy enough to damage your guitar when doing so.

[feyshay]

I did the Acoustic Cloud technique above and found that what ever bowing that is there is probably that which came with the guitar. I've put on lighter strings and will evaluate further.
Thanks. Hopefully the great tips above will be useful for others too.

[travisbrown]

Hi feyshay

I don't mean any disrespect, but it sounds like you are novice enough with guitar setup that you should take it to a tech. There is lots of good advice here from Acoustic Cloud et al; however, it sounds like you are spending a lot of time on something that should be a quick fix. A good tech will explain what they are going to do and why. They will also be receptive to your questions.

Just say, "I want this guitar set up for medium strings." If there are any other issues with the guitar, your tech will identify them quickly.

If you want to research more, there is excellent advice at MIMF: Guitar Building: Acoustic Guitar Building, Electric Guitar Making, Archtop Guitar Building, Guitar Repair, Violin Making, Dulcimer Making, Mandolin Building, Banjo Building, Drum Making!. I know lots of the people there and they are all very helpful.

[feyshay]

I think you're right. It takes me 1/2 hour to change strings. Things go very slow and everything is a learning process, including guitar maintenance. I don't want to have to rely on an expert for everything, but I really have no carpentry or mechanical skills. At least my guitar playing is coming along.

[travisbrown]

No worries. You'll pick it up quickly.

[Acoustic Cloud]

Originally Posted by feyshay

I think you're right. It takes me 1/2 hour to change strings. Things go very slow and everything is a learning process, including guitar maintenance. I don't want to have to rely on an expert for everything, but I really have no carpentry or mechanical skills. At least my guitar playing is coming along.

Hey bro-ham,

Being thrown in the pool is most times better than studying "swimming" for a long time. I was thrown in the pool close to 15 years ago, when the store I had taught guitar at for years lost its techie guy. I became the man. I guess I didnt have a vote.

So after blumbling along for a bit, the pretty hardcore OJT with no teacher, made me learn and move faster than I would have liked to.

ANyway, after hundreds of repairs and setups each year, I learned...sometimes the hard way. Reading manuals and things are always good, but there is nothing like the SLAP of the chlorine that makes ya do it!