Lack of sustain in some notes

[maturanesa]

I have this problem with my fender JB MIM.
Some notes have a poor sustain in comparision with another notes on the fretboard. For example: A string, 4 fret (poor), A string 7 fret (ok). G string, 7 fret (the note create an harmonic and die in few seconds). G string, fret 12 (ok).. etc

The action string per string is about (measuring the end of the fingerboard and string distance):

G: 3 mm
D: 3.2 mm
A: 3.5 mm
E: 4 mm

The height in the bridge is about exactly the radius of the fingerboard, and the nut create this diferences...

What i should do?

thanx

[RBrownBass]

What you're describing as poor sustain is a "dead spot"- characteristic of many Fender basses and, allegedly, other brands as well (two of my MIA Fenders had noticeable dead spots, none of the other brands that I've owned had them that I could hear. I'm, you know, one in a billion). But don't worry about it. Always remember that 1) Leo got it right the first time, 2) Dead spots impart character and soul to your tone and make your bass sound the way a bass should, and 3) Jaco didn't need even notes up, down and across the fingerboard. If in doubt, refer to rule #1. If it's on a Fender, it's a Good Thing.

[maturanesa]

Originally Posted by Auriaprottu

What you're describing as poor sustain is a "dead spot"- characteristic of many Fender basses and, allegedly, other brands as well (two of my MIA Fenders had noticeable dead spots, none of the other brands that I've owned had them that I could hear. I'm, you know, one in a billion). But don't worry about it. Always remember that 1) Leo got it right the first time, 2) Dead spots impart character and soul to your tone and make your bass sound the way a bass should, and 3) Jaco didn't need even notes up, down and across the fingerboard. If in doubt, refer to rule #1. If it's on a Fender, it's a Good Thing.

thanx, i never realized that. At first time i thought it was my neodynium pickups that have very strong magnets and that was messing the sustain. But the strange thing was that some notes in higher frets have more sustain than others in the upper

[SnakeKappele]

I hate dead spots! If I need to hold a note, I don't want to deal with the note I want to hold being dead at certain places on the neck. First of all, listen for the dead spots through headphones. Room acoustics can and will increase some and decrease other frequencies (my room eats Fs). If the problem is with the room: change the direction/location of the amp and/or goof with the EQ.

If the problem is in the bass, you have five options I know of:

1) Check the neck/body joint. I have found that the neck/body joint it crucial. I removed the dead spots from my two basses that had dead spots by removing the factory installed neck shims and paint in the neck pocket. The key is to have the best possible wood to wood contact between the neck and body for clean vibration transfer.

2) Replace the neck. Replacing the neck with a high quality neck like a Warmoth which uses steel reinforcement rods for rigidity and removing dead spots should solve the problem. Unfortunately, the neck can cost as much as the bass and you won't know for sure that it will fix your problem until you have spent the money.

3) If weight is added to the headstock (like with a FatFinger), the dead spot(s) will move toward the headstock. If the dead spot is close to the nut, you may be able to remove it this way.

4) If weight is removed from the headstock (like with ultra light tuning machines), the dead spot(s) will move toward the bridge.

5) The worst option - live with it. I can not accept this option. Until I figured out the neck pocket problem with my basses with dead spots, I stopped playing them.

Good luck!

[Turnaround]

Originally Posted by maturanesa

I have this problem with my fender JB MIM.
Some notes have a poor sustain in comparision with another notes on the fretboard. For example: A string, 4 fret (poor), A string 7 fret (ok). G string, 7 fret (the note create an harmonic and die in few seconds). G string, fret 12 (ok).. etc

The action string per string is about (measuring the end of the fingerboard and string distance):

G: 3 mm
D: 3.2 mm
A: 3.5 mm
E: 4 mm

The height in the bridge is about exactly the radius of the fingerboard, and the nut create this diferences...

What i should do?

thanx

This illustrates the nature of dead spots perfectly.

"Dead spots" are really "dead frequencies". The bass as a unit will have a certain frequency that is it's resonant frequency - that is the frequency it would produce if it were tapped or struck (like a drum). It's the natural frequency of the instrument.

When you pluck a string, some of the energy of the vibration is transmited to the instrument (body and neck as a unit). The closer the frequency of vibration of the string is to the resonant frequency of the instrument, the more of the string energy will be absorbed by the instrument. [High school science - sympathetic vibration] And the more string energy that is absorbed by the instrument, the less energy is left to keep the string vibrating. So the string vibration dies faster at the resonant frequency of the instrument - or multiples and whole fractions of that frequency - i.e. octaves of the note.

If you check the posting above you will see that the player complains of "dead spots" on A string at fret 4 and on G string at fret 7. The notes produced at those locations are D. If you were to do a vibration analysis on the bass you would find that the resonant frequency of the instrument is D.

In this case we are seeing a typical "dead note" problem. And the idea of adding or removing mass works (to a degree) because as you change the mass, such as by adding a a Fat Finger, you will move the resonant frequency. An therein lies the problem - where to move it to. If D is a problem, how about Bb? F? Ab? You might think that killing the resonance of the instrument entirely would be a good idea, but that has been tried and the results were not very popular. As an example, "Plexiglas" has a very low resonance characteristic, but the Armstrong basses made from it were not known for having very good tone. Many makers insist on using "tone woods" which by definition are resonant and consequently have a resonant frequency.

So you get to choose - a "resonant instrument" with a natural organic woody tone with an associated "dead frequency" problem, or a non resonant device that lacks character, but without dead spots. Granted, the "lacks character" comment is a matter of opinion, but many reviewers have made such observations about basses that are not very resonant.

Hopes this helps in understanding of what's going on with dead spots.

[darkstorm]

Snake.."1) Check the neck/body joint. I have found that the neck/body joint it crucial. I removed the dead spots from my two basses that had dead spots by removing the factory installed neck shims and paint in the neck pocket. The key is to have the best possible wood to wood contact between the neck and body for clean vibration transfer".

Yup. If a shim is needed. I'll put some wood glue on it and in the pocket itself to act as filler/tightner for neck joint. So no air gap from shim. It helps isntruments whose neck joint isnt ideal to have less noticeable dead notes if it has that.