Intonation and Setup Confusion

[Jinro]

I've done my research regarding DIY setups and intonation fixes, but none of the articles give a good overview of specific intonation problems other than at the 12th fret. I also have run into an odd problem.

I'll start with the odd problem:

On my old starter bass, Ibanez Gio, the intonation is horribly sharp at the 12th fret on the E. I adjusted the saddles so that the 12th was playing in tune, only to find that my open E (and most of the lower frets) was now playing horribly flat. So I tune the open string back up to E, check the 12th fret, and it's horribly sharp again. Once again move the saddle to fix the 12th, and it detunes my open string again. Tune my open string back up, and the 12th fret is back to playing sharp AGAIN. Either I'm doing something wrong, or my bass is just fudged.

Second question, is adjusting the saddles only for fixing intonation at the 12th fret? What about the intonation elsewhere? I have a 5-month old SR505 that had perfect intonation until I put new strings on it. The action stayed low to my liking, but initially the 12th fret of all strings was sharp. After about a month it settled down and now the 12th frets are perfectly fine, but almost all the frets between 1 and 11 are just a tad sharp. Being slightly OCD I want to fix all these but I'm not sure if that's how they're supposed to be, or if I need a truss rod adjustment, or what.

[Febs]

Originally Posted by Jinro

On my old starter bass, Ibanez Gio, the intonation is horribly sharp at the 12th fret on the E. I adjusted the saddles so that the 12th was playing in tune, only to find that my open E (and most of the lower frets) was now playing horribly flat. So I tune the open string back up to E, check the 12th fret, and it's horribly sharp again. Once again move the saddle to fix the 12th, and it detunes my open string again. Tune my open string back up, and the 12th fret is back to playing sharp AGAIN. Either I'm doing something wrong, or my bass is just fudged.

You're doing it correctly. Moving the saddle will always impact the pitch of the open string, because you're changing the length of the string. It is an iterative process. Tune the open string back to pitch, and then repeat the process of checking the 12th fret harmonic against the fretted note and adjusting the saddle as necessary.

[Gaius46]

Originally Posted by Jinro

I've done my research regarding DIY setups and intonation fixes, but none of the articles give a good overview of specific intonation problems other than at the 12th fret. I also have run into an odd problem.

I'll start with the odd problem:

On my old starter bass, Ibanez Gio, the intonation is horribly sharp at the 12th fret on the E. I adjusted the saddles so that the 12th was playing in tune, only to find that my open E (and most of the lower frets) was now playing horribly flat. So I tune the open string back up to E, check the 12th fret, and it's horribly sharp again. Once again move the saddle to fix the 12th, and it detunes my open string again. Tune my open string back up, and the 12th fret is back to playing sharp AGAIN. Either I'm doing something wrong, or my bass is just fudged.

Second question, is adjusting the saddles only for fixing intonation at the 12th fret? What about the intonation elsewhere? I have a 5-month old SR505 that had perfect intonation until I put new strings on it. The action stayed low to my liking, but initially the 12th fret of all strings was sharp. After about a month it settled down and now the 12th frets are perfectly fine, but almost all the frets between 1 and 11 are just a tad sharp. Being slightly OCD I want to fix all these but I'm not sure if that's how they're supposed to be, or if I need a truss rod adjustment, or what.

AFAIK intonation can only be done on the open note and the octave. In essence a string sounds a particular note when it vibrates. It sounds the same note - an octave higher - when the string length is cut in half. When you're adjusting the saddles you're making sure the string length at the 12th fret is half the total string length.

When the intonation is correctly done the open and 12th fret should sound the same note. Other notes may be a little sharp or flat but that's a problem with all fretted instrument. There isn't much you can do about it.

[JLS]

Originally Posted by Jinro

I've done my research regarding DIY setups and intonation fixes, but none of the articles give a good overview of specific intonation problems other than at the 12th fret. I also have run into an odd problem.

I'll start with the odd problem:

On my old starter bass, Ibanez Gio, the intonation is horribly sharp at the 12th fret on the E. I adjusted the saddles so that the 12th was playing in tune, only to find that my open E (and most of the lower frets) was now playing horribly flat. So I tune the open string back up to E, check the 12th fret, and it's horribly sharp again. Once again move the saddle to fix the 12th, and it detunes my open string again. Tune my open string back up, and the 12th fret is back to playing sharp AGAIN. Either I'm doing something wrong, or my bass is just fudged.

Second question, is adjusting the saddles only for fixing intonation at the 12th fret? What about the intonation elsewhere? I have a 5-month old SR505 that had perfect intonation until I put new strings on it. The action stayed low to my liking, but initially the 12th fret of all strings was sharp. After about a month it settled down and now the 12th frets are perfectly fine, but almost all the frets between 1 and 11 are just a tad sharp. Being slightly OCD I want to fix all these but I'm not sure if that's how they're supposed to be, or if I need a truss rod adjustment, or what.

You need to get the 12th fret harmonic, and the fretted 12th fret note, in tune. Yes, when you move the saddle to change the pitch of the fretted note, you will have to retune and recheck.

As to OCD notes: if you can't hear that they're out of tune, they're not. If you are one of these types that goes after every note on the fingerboard with an electronic tuner, you are setting yourself up for a fall.

[JLS]

Originally Posted by Gaius46

AFAIK intonation can only be done on the open note and the octave. In essence a string sounds a particular note when it vibrates. It sounds the same note - an octave higher - when the string length is cut in half. When you're adjusting the saddles you're making sure the string length at the 12th fret is half the total string length.

When the intonation is correctly done the open and 12th fret should sound the same note. Other notes may be a little sharp or flat but that's a problem with all fretted instrument. There isn't much you can do about it.

Sorry, this is flat wrong.

[electracoyote]

Good advice here.

Also, excessive relief and shallow nut slots can make intonation along the fretboard difficult.

After my intonation efforts, I play all variations of octaves all over the fretboard, in all positions. I usually get perfect octaves all over, no wobble.

[Meyatch]

Originally Posted by Jinro

...I adjusted the saddles so that the 12th was playing in tune...

This is what you are doing wrong.

Tune the open string to pitch, if the 12th fret is sharp, move the bridge saddle further from the neck, if it is flat, move it closer to the neck.

Do not move it until it is in tune, just move it a little bit at a time.

Tune the open string, check again, repeat as necessary.

[JP Morin]

Originally Posted by JLS

You need to get the 12th fret harmonic, and the fretted 12th fret note, in tune. Yes, when you move the saddle to change the pitch of the fretted note, you will have to retune and recheck.

As to OCD notes: if you can't hear that they're out of tune, they're not. If you are one of these types that goes after every note on the fingerboard with an electronic tuner, you are setting yourself up for a fall.

+1 !!!

May I add, check the threads here on the warwick forum, it may help you, the principe is the same with other bridges:

Frequent Screwing: pickup height & intonation

and this video from the same site :

Warwick Basses Amps & Rock'n Roll

The guy there said that he also check at the 24 fret if you have and use a lot note above the 12th fret... I tend to do that and when it's seems all in tune I verify with the same notes/octaves on different strings to see how they are in relation and if I did a god job...

[PazzoBasso]

For accurate intonation across the whole fretboard, you're frets would like kinda like this:




here's more info:

True Temperament - Fretting systems

[MglMatador]

What you basically want to do is to make the length of string between the nut and 12th fret the same as the length of string between the 12th fret and the bridge saddle (accounting for the thickness of the string). Every time the saddle position is adjusted, the open string must be retuned. I assume that you know that you need to move the saddles away from the neck to correct what you are seeing.

As was noted above it almost sounds like excessive relief / high action is causing the sharpness. What is the distance between the E string and the top of the 12th fret (with the bass in playing position)? If the action is high, the act of fretting the string at the 12th fret may be pulling it sharp due to the increase in tension.

How sharp are we talking about here? 5 cents? 50 cents?

[Gaius46]

Originally Posted by JLS

Sorry, this is flat wrong.

What's wrong about it? Serious question. If I'm misunderstanding something I'd like to be corrected.

[Jinro]

I noticed a lot of talk about this harmonic at the 12th. This leads me to more confusion. The harmonic will be in tune so long as the open string is in tune, and conversely it will be out of tune when the open string is out of tune. If adjusting the saddle effects the tuning of the open string, then it will also effect the harmonic, leading me back to problem #1.

You need to get the 12th fret harmonic, and the fretted 12th fret note, in tune. Yes, when you move the saddle to change the pitch of the fretted note, you will have to retune and recheck.

And if the fretted note at the 12th returns to it's pre-adjustment state (sharp) after retuning and rechecking, then what?

It is an iterative process. Tune the open string back to pitch, and then repeat the process of checking the 12th fret harmonic against the fretted note and adjusting the saddle as necessary.

So repeat the adjustment over and over again until it's finally playing correctly?

As was noted above it almost sounds like excessive relief / high action is causing the sharpness. What is the distance between the E string and the top of the 12th fret (with the bass in playing position)? If the action is high, the act of fretting the string at the 12th fret may be pulling it sharp due to the increase in tension.

I don't have a proper measuring tool, but using a ruler, 3mm. Distance between the first fret and the string is barely 1mm, so if I lower the action any further I'll probably get fret buzz.

How sharp are we talking about here? 5 cents? 50 cents?

Using a tuner, A string 12th (and everything between 1 and 12) is a little more than half a tick sharp. E string 12th (and everything between 1 and 12) is 1 tick sharp. B string 12th (and everything between 1 and 12) is two ticks sharp.

Obviously I need to adjust my saddles, but last time I did that it got me nowhere. Tuned the open string, checked harmonic, moved saddle so that 12th match harmonic, but the process ended up detuning open string (and harmonic). Retuned open string and checked 12th fret and it was just a sharp as it was before adjusting the saddle.

[MglMatador]

Here is the correct sequence:

1) Tune open string to dead perfect. The 12th harmonic should be perfect as well.

2) Fret the 12th fret. Check the tuning. If sharp, lengthen the string by moving saddle backwards (away from neck) a few turns. If flat, move saddle forwards.

3) Go to step 1.

Immediately after adjusting the saddle you need to retune the open pitch to perfect, then recheck the 12th fret.

If the 12th fret note never changes, then either you aren't actually moving the saddles, or something is wrong with the string.

Try this: if you play the open note, and lengthen the saddle, do the note go flat as you turn the saddle adjustment screws?

[hdracer]

Sounds like you need to set the witness points.
Just one little step that most people forget about.

[Jinro]

What are the "witness points"?

[hdracer]

The witness points are where the string crosses the saddle & the nut.
The point at the saddle is the most troublesome.
With a steep brake angle the string will "float" on the saddle and show the problems you are describing.

After you put the strings on, before you tune to pitch, tug up on the string to seat it in the tuning post and the barrel end seated in the bridge.

Then tune to pitch.
Once the string is tuned take your thumb and push down on the string about a inch to inch and a half in front of the saddle.
I normally do the same at the nut too.

Give it a try.

[electracoyote]

Originally Posted by hdracer

After you put the strings on, before you tune to pitch, tug up on the string to seat it in the tuning post and the barrel end seated in the bridge.

Then tune to pitch.
Once the string is tuned take your thumb and push down on the string about a inch to inch and a half in front of the saddle.
I normally do the same at the nut too.

Give it a try.

Good point, a lot of people probably overlook this.

I push down on the strings on both sides of the saddles and nut if possible. And waiting a day or two for the slight stretch to occur might give more accurate intonation results as well.

[GBassNorth]

Originally Posted by MglMatador

Here is the correct sequence:

1) Tune open string to dead perfect. The 12th harmonic should be perfect as well.

2) Fret the 12th fret. Check the tuning. If sharp, lengthen the string by moving saddle backwards (away from neck) a few turns. If flat, move saddle forwards.

3) Go to step 1.

Immediately after adjusting the saddle you need to retune the open pitch to perfect, then recheck the 12th fret.

If the 12th fret note never changes, then either you aren't actually moving the saddles, or something is wrong with the string.

Try this: if you play the open note, and lengthen the saddle, do the note go flat as you turn the saddle adjustment screws?

This is correct and I suspect the OP is seeing the problem because it appears he might be tuning open then checking at the 12th fret and adjusting the saddles until the 12th fret is in tune. He'll need to adjust the saddles as noted above and then retune the open string THEN check to see what impact it had on the 12th fret tuning (never tune the 12th fret, always tune the open string and then check the 12th fret to see if you need to move the saddle further from the neck if sharp or closer to the neck if flat) and repeate as necessary. I've found that it can take as many as 5 turns on a standard fender jazz bridge to go from relatively sharp to in fully in tune on the 12th fret. Another thing to take into account is that if you are sharp at the 12th fret you may need to actually detune (slacken) your strings so you can move the saddle more freely back away from the neck. This becomes increasingly important in string thru bodies where the break angle of the string may put a tremendous amount of pressure on the saddle and can end up causing you to strip the adjusting screw if the saddle can't easily move.

[Jinro]

This is correct and I suspect the OP is seeing the problem because it appears he might be tuning open then checking at the 12th fret and adjusting the saddles until the 12th fret is in tune.

That is indeed what I'm doing, and apparently the source of my problem

Now that I know the proper way to set the intonation I should be good now.

Ok, I got the strings fixed. E through G are good. B is the oddball. I've got the 12th as close as I can get it (still just a hair sharp), but I had to move the saddle almost all the way to the bottom. The other annoying thing is that while the 12th is playing in tune, all of my fretted notes along the B are still a whole tick mark sharp on the tuner. I tried lowering the action but can't go any further without buzz. Does this call for a truss rod adjustment?

[JLS]

The other annoying thing is that while the 12th is playing in tune, all of my fretted notes along the B are still a whole tick mark sharp on the tuner. I tried lowering the action but can't go any further without buzz. Does this call for a truss rod adjustment?

Is this a trollpost? Are you jerking our chains?