Guitar tuning and intonation

Norman86 · 2010-08-20T18:08:24+00:00

So, im posting this here as it might be a really dumb question. if your guitar is in tune, with an electronic tuner no less, would it be possible that that...

Guitar tuning and intonation

Gearhead

First thing: intonation has got F%k#ll to do with your lead.

Second thing: the difference between tuning and intonation.
Tuning is making sure an open (unfretted) string is in tune.
Intonation is making sure that as you fret a string, the fretted note is in tune if the string is tuned.

The thing with strings is that if the tension goes up, the pitch of the note goes up. While you are fretting, you are pushing down onto the string. So the tension goes up.
Now you would say, yeah, but don't they put the frets in the right place to compensate for this? No. They put the saddle at the bridge side in the right place to compensate for this.

To further complicate this story, the pitch increase as you fret the string depends on four things:
- the intonation adjustment at the bridge (as discussed above)
- the action (the further you have to press the string down, the more tension you add)
- the string gauge (thicker strings tension more at the same deflection, you will see that the compensation at the saddle is less)
- nut height (too high means you cannot get the lower frets to be in tune regardless of the bridge compensation)
So the guy that says he has to 'set up' the guitar means that he will also have a look at the action, nut height and some other things.

If you still have trouble with fretted notes not being in tune after a good setup, you ought to be a little less ham-fisted about fretting ?

DonovanB

Gearhead seems to have missed one point.

The way a guitar works is that the string is suspended between the nut and the bridge. The note relies on the length between those two points, the tension of the string and the density (thickness but not quite) of the string. All the factors make the note so all have to be right.

When you push down on, say, the 5th fret you have shortened the distance between the suspended points, effectively making the string shorter. This makes it vibrate at a higher frequency and the note gets "higher."

Pushing it down also increases the tension. As does pushing it down, then bending it upwards while keeping it pressed.

If the balance between Distance and tension is not right, when you push down on the 5th fret, the distance will be wrong, and the tension will be wrong. This means the note don't hear the note you are supposed to hear.
That is when your intonation is out.

as gearhead said the saddles are moved closer or further from the neck to get the distance right. Your action could affect it as well so it is a good idea to get the guitar set up correctly.

The scientific way to explain it is that a string will vibrate a certain amount of times per second. The note A should complete 440 cycles per second. If your tension or length are incorrect it may vibrate more or less, like at 450 cycles per second making it the wrong note.

(this is way harder to explain in writing that I thought it would be)

Renesongs

if your guitar is in tune, with an no less, would it be possible that that intonation could be out?

The short answer is Yes. A simple test is for each string tune the sting with your electronic tuner on the open string and see if it reads the same when fretting on the 12th fret. If not that strings intonation is out.

Gearhead

so whot did I miss then? 8)

FenderBender

Alan explains it nicely here: http://articles.guitarforum.co.za/articles/guitar-maintenance-5-%E2%80%93-setting-intonation

Wizard

The neck frets are calculated so the 12th fret is exactly half the length of the string.
If so, this resonates at double the frequency - i.e. same note an octave higher.
If the 12th fret note isn't exactly an octave higher, the string length needs to be changed (since you can't change the position of the frets)
You make the string longer or shorter with adjustments at the bridge.

And yes ... I know you all knew this ...

Norman86

Firstly, regarding my lead...
the lead was replaced (eventually) as it was faulty!
but it wasnt because of the lead that the guy said the intonation was out!
he was playing my guitar to check that the cable that was swapped out wasnt also faulty, and then spoke of getting me to get them to set up the guitar because of this and that reason and that the intonation is out. cant remember all he said!
as i say though, im just not sure whether he was just trying to make a sale again!

Secondly, regarding the intonation...
? :-[ OH MY WORD!
This is WAY more complicated than i thought! it probably makes sense when you know what the note should sound like.
but not knowing all this makes it complicated for a novice...
i mean, i have a love for music, but i wouldnt know an A chord from a B chord if it slapped me in the face!
take note though, it will change in the near future when i get taught all these things!
so for now, i think i will just leave the set up to my teacher! whom i hopefully will be seeing soon!
just need to make arrangements to get to each other!

Thank you to all for the replies and trying to help me understand!
It is much appreciated! one day i will be on the same page as you guys! ?

AlanRatcliffe

Renesongs wrote:
if your guitar is in tune, with an no less, would it be possible that that intonation could be out?
The short answer is Yes. A simple test is for each string tune the sting with your electronic tuner on the open string and see if it reads the same when fretting on the 12th fret. If not that strings intonation is out.

+1 Rene. That answers the actual question without getting more technical than needed and gives a simple way to check. Thanked.

@ Norman. You must let the store set up the guitar for you. Don't worry about the whys and wherefores - the simple fact is they sold you the guitar so they will likely set it up for you for free, as part of the sale. Let them worry about it.

Bob-Dubery

Norman86 wrote:
This is WAY more complicated than i thought! it probably makes sense when you know what the note should sound like.
but not knowing all this makes it complicated for a novice...
i mean, i have a love for music, but i wouldnt know an A chord from a B chord if it slapped me in the face!

You don't have to. You'd hear it though. You'd tune your guitar to whatever tuner you use, and find that as you go up the neck it sounds less in tune. You wouldn't have to know that you're trying to play a C# and it's 33 cents flat, but you would notice that it doesn't sound right.

At least now you know it's poor intonation and not you.

costafonix

just my 2 cents ? worth, I have found that some tuners are not as accurate as others,,,so choose a good quality tuner when setting your intonation. I also check the harmonic on the 12th fret as well as fretting the 12th fret (you can see a subtle difference). Other obvious things are ensuring the nut is clean (i.e. not choking the strings) and of course use new strings.....

Gearhead

CostaFonix wrote: you can see a subtle difference

And here's me thinking that the idea is that you don't see any difference ?

costafonix

aah,,, you need a good eye 8)

vic

CostaFonix wrote: just my 2 cents ? worth, I have found that some tuners are not as accurate as others,,,so choose a good quality tuner when setting your intonation. I also check the harmonic on the 12th fret as well as fretting the 12th fret (you can see a subtle difference). Other obvious things are ensuring the nut is clean (i.e. not choking the strings) and of course use new strings.....

Tuning and intonation are not related......you can tune your open E string (say) to any note, BUT the corresponding note at the 12th fret should then sound exactly one octave higher (to the ear). That is intonation. If it does not you have to adjust at the bridge. Also make sure your strings are in good condition because an old rusty and fatigued string will not "follow the rules".

costafonix

Agreed Vic, I never elaborated that you obviously need to adjust your intonation at the bridge. Either way, you'll need a tuner to check your accuracy on the note you are 'setting'? No?

vic

CostaFonix wrote: Agreed Vic, I never elaborated that you obviously need to adjust your intonation at the bridge. Either way, you'll need a tuner to check your accuracy on the note you are 'setting'? No?

Yes...only for tuning to a standard note, but not necessary for intonation purposes. As I said, for intonation checking, you can tune any open string to any note, BUT the corresponding note on the 12th fret of that string, should sound exactly one octave higher (to the ear) than the open string. Hope it makes sense.

Norman86

Sjoe...
looks like i really opened a can of worms here hey?! :-[

now, this was more of a pondering question to be quite honest!
i was just curious as to how this could be possible!

Is my guitars intonation out? i honestly dont know!
But my teacher will soon let me know!

Thank you for the replies! while its a little intimidating, it is quite interesting!

Thanks again!

Sean

Norman86 wrote: Is my guitars intonation out? i honestly dont know!

Do you have a tuner? If yes, then pluck one open string (say 1E) and tune it. When it's in tune, fret the string at the 12th fret (the same 1E) and pluck it again. If the indication on the tuner is the same as it was when you plucked the string un-fretted, then the intonation is fine. Do this for all the strings. Then you will honestly know ? Unless of course you don't have a tuner, then you won't ?