Strange happenings in upper register

[echo008]

Hi Guys I am having a problem with my Geddy Lee.

With the bass tuned everything is fine from the 1st fret to about the 12th.
After that the bass is out of tune and it also sounds like there is a Chorus effect coming through the PuPs (I dont know how else to explain it). The bass just acts crazy From around the 12th fret up.

Is this intonation? I know its not strings I already tried swapping.

any help is appreciated!
thanks
- Tom

[Dogbertday]

if the harmonic over the twelfth fret isn't the same as the note pressed down in the same spot then your intonation needs to be set. This is done at the bridge by lengthening or shortening the string.

[perucci]

Intonation is set both at the 12th fret and (if I recall) 19th fret; compare the harmonic with the fretted note. The 19th fret intonation is not normally mentioned/done, but gives you better intonation. If intonation is off, the string doesn't vibrate "true".

Note: I've heard people say that the pickup height can affect the sound too.

[echo008]

Thanks Guys... so you are saying the trouble with intonation can account for both the off tuning and the strange Chorus effect Im hearing in that register?

- Tom

[perucci]

Originally Posted by echo008

Thanks Guys... so you are saying the trouble with intonation can account for both the off tuning and the strange Chorus effect Im hearing in that register?

- Tom

Definitely the tuning, but yes, bad intonation can make the string "vibrate funny". A string doesn't just vibrate end-to-end, but additionally vibrates in fractions (halves, thirds, fourths, etc.):


When the intonation is off, as I understand it, the string can't vibrate "true". Although you're fretting a note, I'm guessing, that the portion of the string between the nut (not bridge) and the fret is still a factor. Physics aside, it does seem to be an issue.

I did a quick Google search, and in a Ric forum (guitar), someone observed that if you intonate a Ric guitar "too well", you loose the characteristic Ric "chorus" sound.

[knuckle_head]

Pups too close to strings can cause chorusing as well.

[echo008]

Originally Posted by perucci

Definitely the tuning, but yes, bad intonation can make the string "vibrate funny". A string doesn't just vibrate end-to-end, but additionally vibrates in fractions (halves, thirds, fourths, etc.):


When the intonation is off, as I understand it, the string can't vibrate "true". Although you're fretting a note, I'm guessing, that the portion of the string between the nut (not bridge) and the fret is still a factor. Physics aside, it does seem to be an issue.

I did a quick Google search, and in a Ric forum (guitar), someone observed that if you intonate a Ric guitar "too well", you loose the characteristic Ric "chorus" sound.

I appreciate this and it is interesting!
Ill try and reset intonation and see what I will see. Ill also look at the pickup height if simply fixing the intonation does not help it but hopefully it will.

very cool guys thank you for your help
- Tom

[Dan1099]

The "chorusing" is from the pickups being too close to the strings. It's common on jazz basses. Lower your pickups or raise your strings.

[echo008]

Originally Posted by Dan1099

The "chorusing" is from the pickups being too close to the strings. It's common on jazz basses. Lower your pickups or raise your strings.

... Ill intonate then drop PuPs if need be thanks