Intonation problem: New American Standard P bass

[BillMason]

All of my strings tune at open and at the 12th fret harmonic, but fretted notes on my E string only are just a slight bit sharp - noticeable when played with the band. How do I fix this?

By the way, these new bridges do not use Phillips head screws. It's a hex screw slightly smaller than 3mm, I forget which one I used, but I had to dig in my toolbox for it, as the two that came in the case do not fit.

[()smoke()]

you mean 12th fret, fretted right?

when you set your intonation, you tuned the fretted 12th fret to the harmonic?

[BillMason]

The 12th fret harmonic and the open string are both in tune with a chromatic tuner. The 12th fret fretted, and the ones above it are slightly sharp.

[nemo]

Hi, it looks like you have to move back the bridge saddle.
A good guide is here:
http://www.garywillis.com/pages/bass...ntonation.html

[()smoke()]

Originally Posted by BillMason

The 12th fret harmonic and the open string are both in tune with a chromatic tuner. The 12th fret fretted, and the ones above it are slightly sharp.

i see...it's the fretted 12th fret note that you need to compare to the harmonic or open note to set the intonation

i'm sure the above link will be helpful, and yes, if the fretted note is sharp when the harmonic is in tune, move the saddle backwark away from the fretboard and check/repeat until they match

[didier]

just as way of a little non-technical explanation-

If you think about it, fretting a note is going to add a little tension (as you puch down you increase ever so slightly the distance the string has to travel from nut to bridge.)

The higher your action, the more likely the fretted will vary from the harmonic. There are lots of other factors, of course. Main thing though, is that you probably want the fretted notes intonated versus the harmonics.

[JustOpenYourMind]

No matter how the intonation is set, the open string and 12th fret harmonic are always going to be the exact same note. it has nothing to do with the frets or intonation, the 12th fret is approximatly right in the middle of the string, doing an harmonic there produces a note an octave above the open string.

To set intonation you have to adjust the bridge screws until the open string and the 12th fret fretted note are at the same pitch.

[COOL AND DEADLY]

Thanks, I have this problem with my Marcus Miller too. Can the bridge screws be adjusted while the strings are on, tuned? Should I loosen or remove them? I think it should be fine to adjust them with the strings on, but i'm not positive.

[JustOpenYourMind]

you leave them tuned, you turn little at a time and check often with a tuner till you get it right

[()smoke()]

Originally Posted by COOL AND DEADLY

Thanks, I have this problem with my Marcus Miller too. Can the bridge screws be adjusted while the strings are on, tuned? Should I loosen or remove them? I think it should be fine to adjust them with the strings on, but i'm not positive.

you can leave the strings on for this, and i generally only detune slightly if i need to move the saddle backward (away from the headstock) so that i can make sure it doesn't bind the string between the saddle and the bridge anchor point--just enough so that the bridge doesn't 'pinch' the string as you adjust it backwards...(some bridges/saddles/strings are worse about this than others, just a general observation)

when doing a full setup, i usually initially set the bridge saddles slightly further back than i know they'll need to go for proper intonation so that i can avoid having to adjust them backward once i'm tuned to pitch

[Solarmist]

Remember - when setting intonation - if you have large/jumbo frets themselves, and checking it with a tuner - don't press real hard between the frets for the 12th fret note against the harmonic note. Press just enough so the note is clear-just behind the 12th fret as pressing down on it hard slightly stretches the string thus sharpening the note ever so slightly.

[warnergt]

Wouldn't it be more logical to set the intonation while pressing with the same pressure you use to play? After all, you want the notes at the right pitch when you're playing; not just when you're lightly pressing the string.

[BillMason]

Never mind - I don't know what I was thinking, it must have been a brain cramp when I posted that. I fixed the intonation no problem. It was off quite a bit because (I think) I had removed the bridge when I changed strings, just to have a little look, and also (I think) because I switched from 8250s (taperwound) to 7250s.

Mind you, I do think it odd that the new bridges use a hex screw instead of a Phillips, and no tool was provided. Of the two allen keys provided, one is for setting action, and the other is too big to fit the intonation screw.

[xshawnxearthx]

i'm glad i read this actually. i've been doing intonations wrong. one book i had said match the open and harmonic. which after reading this i realize it's wrong. so i set it up perfectly and now it's all sorts of in tune.