Intonation puzzle

[floatingaxe]

I realized the other day at practice that the intination is off on my lower frets.
The bass is set proper at the 12th fret, but the first fret on all strings are sharp.
Any ideas?

[Jimbob Jones]

It could be your nut is in the wrong place, it's very common on less expensive instruments; I would take it to a decent tech or luthier to get the nut set right.

[mongo2]

It's also possible and more likely that the nut slots are too high and could used to be dressed down a bit by a good tech.

[Turnaround]

Could be that the instrument just isn't strung properly. It's always amazing to me how many players don't seat their strings properly at the nut and bridge. A poorly seated string will not intonate correctly resulting in a string that won't intonate at the 12, or if it does it's off elsewhere.

[electracoyote]

First stop: Nut slot depth.

[Turnaround]

Originally Posted by electracoyote

First stop: Nut slot depth.

No - first stop is to make sure the strings are seated properly. If they aren't and you check the nut slot depth, you will be fooled by the string rise past the nut.

[floatingaxe]

The strings have been on for a couple months so they're probably seated fine in the nut.
It is possible that the slots are a little too shallow. What is the best way to measure this?
I recently changed the bridge, but I don't see how that would effect things. Obviously I needed to re-intonate after, but I'm not sure why it would create this problem.
I believe that my strings are set as low as possible without buzzing, but I will check that as well.

[Jimbob Jones]

If the slots are too narrow, then the strings will never sit down properly, that would definitely be the first thing to check.

[tangentmusic]

Originally Posted by floatingaxe

The strings have been on for a couple months so they're probably seated fine in the nut.
It is possible that the slots are a little too shallow. What is the best way to measure this?
I recently changed the bridge, but I don't see how that would effect things. Obviously I needed to re-intonate after, but I'm not sure why it would create this problem.
I believe that my strings are set as low as possible without buzzing, but I will check that as well.

Are the newer strings the same gauge as the previous set?
Strings setting properly in the nut, and wound correctly on the peg will make a differance. A 4 string bar as opposed to a 2 string tree may help

[electracoyote]

Originally Posted by Turnaround

No - first stop is to make sure the strings are seated properly.

Seated properly? Oh, you must mean the string spacing at the bridge. Yes, that's pretty obvious, but you can still intonate a string even if the string spacing is not consistent at the bridge. OP said he got all open strings and 12th frets to intonate.

The culprit now points to being the nut.

Do you mean "are the slots wide enough?" That's what I meant, depth and width must be appropriate to the strings and the fret height at the first fret.

Let me clarify for the hair-splitters out there: CHECK THE NUT SLOTS FIRST. Regardless what else might be wrong with the set-up, this is an oft-overlooked and extremely important part of making a bass play well.

I'm betting that if OP got his string spacing perfect at the bridge, he would still have intonation problems caused by the nut.

[anonymous02282011]

what strings are these anyway?

I've had issues with specific strings.

[JLS]

Originally Posted by Jimbob Jones

It could be your nut is in the wrong place, it's very common on less expensive instruments; I would take it to a decent tech or luthier to get the nut set right.

I sincerely doubt that...

[floatingaxe]

The strings are D'Addario nickle rounds.
The bass doesn't have string trees.
My guess is slot depth.
What should they measure? (5-string BTW)

[anonymous02282011]

Originally Posted by floatingaxe

The strings are D'Addario nickle rounds.
The bass doesn't have string trees.
My guess is slot depth.
What should they measure? (5-string BTW)

hmm. yea the D'addarios should be good. It's something else . . .

[Turnaround]

Originally Posted by electracoyote

Seated properly? Oh, you must mean the string spacing at the bridge.

No, I mean "seated properly" i.e. fitting properly into the nut slot and forming a proper break angle over both the nut and the bridge.

[JLS]

Originally Posted by mongo2

It's also possible and more likely that the nut slots are too high and could used to be dressed down a bit by a good tech.

I agree; this is the most likely scenario. If the nut slots aren't deep enough, you're squeezing the strings down to the frets, making them sharp.

[electracoyote]

Originally Posted by Turnaround

No, I mean "seated properly" i.e. fitting properly into the nut slot and forming a proper break angle over both the nut and the bridge.

We're on the same page dude.

In simpler terms, have someone who knows what they're looking at look at the nut first.

[Chrisk-K]

The nut slots are too high. File them.

[Zooberwerx]

Shim everything...the nut, the neck, and the bridge. Put some in your shoes while you're at it. J/K.

Stop at Pep Boys and get yourself a set of cheap ($4) feeler gauges. Hold each string down directly above the 3rd fret and measure the gap between the string and first fret. Should be in the .003-.005" range. Any higher than that and you may have intonation problems...but you already knew that. As always, set your "witness points" at the nut and bridge before measuring anything.

Riis

[floatingaxe]

Thanks everyone for your help.

The prize goes to Zoob for actually giving me numbers to use to figure this out (and for having one of the best sigs around here).