Intonation help

[googlydog]

Trying to adjust the intonation on my wife's short scale bass.
It's a weird old frankenstein of different parts, does not seem to have the original neck or bridge.

The intonation is way off. She can tune the strings and have the intonation look fine by checking the harmonics on the 12th fret, but when she actually goes to play any note on any string, it's way sharp. It doesn't matter how close to or far away from the headstock or bridge she's playing, it's always around the same amount off... which is a lot.

The bridge is an old thing where the only movable part is a bar that goes up or down, to adjust the action, but not back or forth. How could I possibly make the intonation better?

I would REALLY appreciate any help and tips for what I can do at home.

 

[ocnor]

She can tune the strings and have the intonation look fine by checking the harmonics on the 12th fret

There's the problem. You don't set the intonation using harmonics.

 

[mcmetal]

If you can't adjust the length of each string you'll have a hard time if it's even possible.You would normally tune your open strings then check the tuning on the 12th fret.By adjusting the length of the string is how you adjust whether it's sharp or flat at the 12th fret.It should hold in tune on both open strings and at the 12th fret when it's intonation is set properly.Raising or lowering your action shouldn't make a difference.I suggest changing the bridge to one that allows you to adjust the string length if she really likes this bass.I know for a fact that if the intonation is off above the 12th fret you'll hear it go out of tune if you play above the 12th fret while recording.check out www.projectguitar.com they have some good tutorials on setting up guitars

 

[Dani Pace]

You mentioned some parts had been changed, possibly the bridge also. Start by checking to see if the bridge is in the correct place. Use a good metal tape measure and check the distance from the 12th fret to the nut, then the distance from the 12th fret to the bridge. Both measurements should be very cloce to the same. With a fixed bridge (like what you described) the 12th fret to bridge will likely be slightly more on the low E and A, slightly less on the D and G. Replacing the bridge with an adjustable one is not usualy a difficult mod, it just takes being careful to get it in the right position. If you are in doubt, a guitar tech can do it fairly fast and should not cost too much to have one installed. Since you mentioned all the notes being sharp the bridge is likely to be a little bit too cloce to the neck.

 

[googlydog]

Yeah, seems like I'll have to replace the bridge. She really likes the bass, since it's short scale it's much easier for her to play than a full-sized bass.

The tuning is as far off on the 12th fret as it is on any other fret. I was reading somewhere that it can get further off the further up the neck you go, but that's not the case on this.

Wish I wouldn't have started fiddling with this three days before an overseas tour... whoops!

 

[ermghoti]

Raising or lowering your action shouldn't make a difference.

Not true. Raising the action, the notes will get sharper, and moreso towards the bridge, lowering causes the inverse. Since this bass is always the same amount out, it's not the action, the bridge (or maybe the nut*) is misplaced.

* If the nut is wrong, tuning the open string to a tuner would put every fret off by pretty much exactly the same amount. This could be the culprit.

 

[ido1957]

Install a new bridge that can be intonated....

 

[mcmetal]

Not true. Raising the action, the notes will get sharper, and moreso towards the bridge, lowering causes the inverse. Since this bass is always the same amount out, it's not the action, the bridge (or maybe the nut*) is misplaced.

* If the nut is wrong, tuning the open string to a tuner would put every fret off by pretty much exactly the same amount. This could be the culprit.

Obviously raising the bridge would sharpen the notes and lowering it would flatten them.There's these things on the headstock called tuning pegs and they should be adjusted after making any adjustments.It doesn't matter where the action is set.It's up to each individual player and their preference and playing style.Once the action is set up to their liking then set the intonation.Like i said intonation is determined by adjusting the length of the string.String height has nothing to do with it.

 

[ermghoti]

Obviously raising the bridge would sharpen the notes and lowering it would flatten them.There's these things on the headstock called tuning pegs and they should be adjusted after making any adjustments.It doesn't matter where the action is set.It's up to each individual player and their preference and playing style.Once the action is set up to their liking then set the intonation.Like i said intonation is determined by adjusting the length of the string.String height has nothing to do with it.

You are wrong. The height of the bridge has more effect on notes near it, just like the depth of the nut slots have more effect on the frets near it. No amount of tuning or lateral saddle adjustment will change that. For example, most new guitars have shallow nut slots, and the first few frets are quite sharp as a result. Bridge height is more forgiving, because of the much greater distance to the last fret, compared to the nut/first fret difference. In any case, you can either fiddle with the saddle and reach a compromise, or you can adjust the bridge and/or nut.

A lot of people compromise intonation to get ideal action, I prefer the other way around.

 

[mcmetal]

Maybe i'm wrong but it's nothing i've had ever had to compromise with.I adjust my action to my liking and adjust my intonation accordingly.I've never had any issues.I don't check every note on every string on every fret of my guitar with a tuner to see that everythings absolutely on.I check my open string tuning and check on the 12th fret and adjust as needed.I've been doing this for years and never had tuning issues.

When my old band recorded some years ago my bass player didn't take the time to check his intonation.On a few songs when he played above the 12th fret you could hear his bass go out of tune.When he played below the 12th fret he sounded fine but you could hear him go in and out of tune throughout the song.That bothers me every time i listen to it and that's why i gave the advice i did to the OP.Playing live i never noticed it,i'm sure maybe others did but when recorded it really stuck out.

I stick with my original advice and think the OP should put on a new fully adjustable bridge and like dani said measure the distance from the nut to the 12th fret and so on.If the holes don't line up right he can fill in the holes and drill new ones.This was done to one of my guitars where the original trem was replaced with a floyd rose,the original holes were filled with a black epoxy or something and were redrilled to accomodate the new trem.It holds it's intonation with no problems and after years of playing it i 've never had any issues with the filler and trem coming loose.

 

[muttley600]

Obviously raising the bridge would sharpen the notes and lowering it would flatten them.There's these things on the headstock called tuning pegs and they should be adjusted after making any adjustments.It doesn't matter where the action is set.It's up to each individual player and their preference and playing style.Once the action is set up to their liking then set the intonation.Like i said intonation is determined by adjusting the length of the string.String height has nothing to do with it.

You are incorrect. Read links in my signature.

 

[ermghoti]

I don't check every note on every string on every fret of my guitar with a tuner to see that everythings absolutely on.I check my open string tuning and check on the 12th fret and adjust as needed.I've been doing this for years and never had tuning issues.

Well, here's the thing: making sure that the 12th fret fretted note is the same as the 12th fret harmonic is not really intonating. Chances are, you're using at least adequately-made guitars, which will be somewhat intonated using that shortcut, but I guarantee if you form a three or four note chord shape, it will be quite noticably out by the time you're at the fifteenth fret or so.

Or, you could d.l. a strobe simulator, and see how far some off the notes will be. The first couple of frets will be sharp, the high frets will fall all over the place, most likely.

Check Muttley's links.

I stick with my original advice and think the OP should put on a new fully adjustable bridge and like dani said measure the distance from the nut to the 12th fret and so on.If the holes don't line up right he can fill in the holes and drill new ones.

If all the notes are equally out, as the OP describes, it can't be the bridge, the notes would be progressively out as they neared the bridge, since the percentage of misplacement changes as you shorten the vibrating string length.

 

[mcmetal]

Guess i'm never too old to learn something new.I'll have to check out the links

 

[Tadpui]

There's the problem. You don't set the intonation using harmonics.

Care to expand on that?

 

[muttley600]

Care to expand on that?

Read the links in my signature.

To those links I'll just add that setting the individual string intonation using the 12th fret harmonic method is really just the start of the process. Because of the way tuning temperament and physics works you need to be aware of many other things that result in implications for tuning and intonating an instrument.

 

[six]

I read the "how to tune your guitar" link, and at first I thought "hey, this might make sense" - but no, I cannot agree with most of what is said.

What's said about tuning to the 5th produced as a harmonic over the 7th fret sounds sensible, but the part about the 3rd in your chords sounding either slightly flat or slightly sharp depending on whether they're minor or major - with a "correctly" tuned guitar of course - really made me doubt about this concept. Hello? It's the same string. So the same C# would once sound flat and once sharp just because it's played once in an Amaj and once in an Bmin... yeah, sure.

Plug your guitar into a tuner, use open strings or 12th fret harmonics, be happy. Lately I've even used the "beginner method" a lot: tune your low E to the tuner and fret it in the 5th fret for you A and so on...

 

[muttley600]

I read the "how to tune your guitar" link, and at first I thought "hey, this might make sense" - but no, I cannot agree with most of what is said.

What's said about tuning to the 5th produced as a harmonic over the 7th fret sounds sensible, but the part about the 3rd in your chords sounding either slightly flat or slightly sharp depending on whether they're minor or major - with a "correctly" tuned guitar of course - really made me doubt about this concept. Hello? It's the same string. So the same C# would once sound flat and once sharp just because it's played once in an Amaj and once in an Bmin... yeah, sure.

Plug your guitar into a tuner, use open strings or 12th fret harmonics, be happy. Lately I've even used the "beginner method" a lot: tune your low E to the tuner and fret it in the 5th fret for you A and so on...

you clearly haven't understood. It is not a concept it is fact. The interval in the two chords you describe are not the same. That is the whole point. Keep in mind that the description and explanations in that link are given by some of the worlds best and most experienced luthiers and is based on in depth knowledge of musical acoustics, an understanding of ancient and modern temperaments and the instruments that those limitations are placed upon.

You can of course use whatever method of tuning you choose but that will not help those that can identify dissonance in many of the chords they play and the OP who wants to understand why his bass will not play in tune.

 

[mcmetal]

I read through those links once before.Yes,it makes sense and i was one those guys for years that had always heard the g string sound a little sharp and would tune it down a slight bit.By doing this it would in fact alter some of the other chords.I noticed it on most open chords that use the g string.

Most times if i was playing something with a lot of open chords i would leave the g string alone.I think if you're playing just a lot of distorted fifth chords you probably won't notice it as much but the clean channel doesn't lie.

Whenever i set my intonation i always use an electronic tuner.I always tune the open strings and then check it on the 12th fret but i've always fretted on the 12th.I've never set it by using 12th fret harmonics.It's the same note so does it make a big difference whether fretting the 12th or using the harmonic?

 

[six]

you clearly haven't understood. It is not a concept it is fact.

With "concept" I was referring to the method they describe to actually tune the guitar.

You can of course use whatever method of tuning you choose but that will not help those that can identify dissonance in many of the chords they play and the OP who wants to understand why his bass will not play in tune.

It's most definitely not due to the way he tunes the bass, not only because it's not about chords with dissonances but single strings that don't produce the note they should when fretted.


@mcmetal:
When setting the intonation, of course you have to _fret_ the note in the 12th fret. A harmonic will always be the exact octave to the empty string, no matter how badly set the intonation is. The fretted note then has to match the harmonic.

 

[muttley600]

With "concept" I was referring to the method they describe to actually tune the guitar.

And that method or a similar one will ALWAYS produce a better intonated guitar in 12 ET. That is the fact part.

It's most definitely not due to the way he tunes the bass, not only because it's not about chords with dissonances but single strings that don't produce the note they should when fretted.

I was pointing out that your advice and comment was both incorrect and of no relevance to the OP. I stand by that. The discussion had moved into discussion about intonation and temperament in general. You have made some comments that are incorrect and I was pointing that out. This is another one

@mcmetal:
When setting the intonation, of course you have to _fret_ the note in the 12th fret. A harmonic will always be the exact octave to the empty string, no matter how badly set the intonation is. The fretted note then has to match the harmonic.

It is not always the best way to set up a guitar to intonate in 12 ET. it is a good start point.

To fully understand intonation, temperament and the physics of a vibrating string requires that you read and understand the links in my sig. Denying that they are correct or in some way flawed is just plain wrong.

Carry on.