Bad intonation across the fingerborad...

[CALopes]

Hi, there!
Well, I've been playing bass guitar for an year and half. My bass is a Rockbass Corvette Classic 5 that I got 2nd handed. So, now I'm starting to notice some intonation issues.
12th fret intonation is ok, but across the rest of the fingerboard, even below 12th fret, some notes are like 10, 13cents sharp and it really pisses me of sometimes. Above the 12th fret some notes get even worse. I did the setup with almost everything by factory recomendation. The only thing different is the nut height, that is just a bit higher as well as the action.

Is it time for me to change bass or is there anything I can do?

btw, I use W's red labels stainless steel.

Thanks in advance

[iiipopes]

Have you had a proper setup on the bass, with a luthier going over everything: making sure the tuners don't slip, proper nut slot depth and contour, frets checked to see if any need dressing, proper pickup height (not too close), bridge adjustments, neck screw proper tightening, and of course, new strings?

You can't tell anything about an instrument until it's had a complete proper setup.

Since it's sharp everywhere but the 12th fret, after a complete setup, see if it's still sharp. If it is, see if adjusting the bridge for everything else gets everything else in tune but for the 12th fret. It is very, very unlikely, but possible, that one fret can be misplaced or miscontoured and throw everything else off.

[CALopes]

Well, I took the bass to a luthier to set it up, but I done myself all the steps you mentioned. I'm not a pro, but I always do the setup myself. Even when I played guitar (3 years ago).
The tuners are fine as well as the nut slots (I did the nut myself with mogno as a upgrade). My fear is that is something going on with the frets 'cos the neck seems fine, I set it up a little flat, but it is fine.
I'll talk with an old guitar maker (my drummer's dad) to see if is there anything he can do.

But I'm still looking for any input from TB people.

[john grey]

When you did your intonation, did you continue to check the harmonic notes up and down; eliminating the possibility of variance of alteration in finger placement? Did you use an analog tuner do you could watch the needle swing?

[JLS]

Originally Posted by CALopes

Well, I took the bass to a luthier to set it up, but I done myself all the steps you mentioned. I'm not a pro, but I always do the setup myself. Even when I played guitar (3 years ago).
The tuners are fine as well as the nut slots (I did the nut myself with mogno as a upgrade). My fear is that is something going on with the frets 'cos the neck seems fine, I set it up a little flat, but it is fine.
I'll talk with an old guitar maker (my drummer's dad) to see if is there anything he can do.

But I'm still looking for any input from TB people.

From your first post:

The only thing different is the nut height, that is just a bit higher as well as the action.

Tuners have nothing to do with intonation; too-high nuts slots, and high action, would contribute greatly to the issue you described.

Hopefully, you got your instrument to someone who knows what he's doing--you'll be much happier, when it's playing as it should.

"Mogno"?

[96tbird]

Did you try... begin by tuning 12th harmonics, then check 12th fretted, adjusting intonation and then checking other positions? I find tuning open strings is unstable enough to be a pain, so I begin with harmonics.

[CALopes]

Originally Posted by 96tbird

Did you try... begin by tuning 12th harmonics, then check 12th fretted, adjusting intonation and then checking other positions? I find tuning open strings is unstable enough to be a pain, so I begin with harmonics.

I'll try tuning that way. Thanks.

BTW mogno is mahogany in portuguese. sorry for that one

[JTE]

Lots of good information above. But first, if the strings are bad, intonation is pretty much impossible to get. A string instrument works on the assumption that the strings vibrate evenly along their entire speaking length. Strings with dirt, grease, funger-funk, etc. won't vibrate true.

And make sure you're using the proper technique for setting intonation- compare the open string or the 12th fret harmonic (if the string is in good shape they ARE exact octaves of each other) to the fretted 12th fret note. I use the harmonic because it's a higher frequency and it gives an electronic tuner a better sample. I mention this again because a recurring problem is that some people mistakenly try to adjust intonation by comparing the harmonic to the open string which does nothing to set the string length in relation to the frets.

It does definitely sound like your nut is too high. Unless you need open strings with a huge attack, there's no reason for the nut to be very high at all. A good check is to fret the string at the third fret an check the clearance between the string and the first fret. You want the string to just barely clear the first fret.

A better test is to fret the string at the first fret and measure the clearance between the string and the second fret. You want the nut to give you the same clearance at the first fret.

John