1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  

Strange B string issues, unwanted overtones/inharmonics - causes/solutions? HELP!

Discussion in 'Hardware, Setup & Repair [BG]' started by DiabolusInMusic, May 23, 2012.


  1. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    I really though I posted this earlier but I couldn't find the original post, so here we go again.... this is a long read and took me a while to write out once today... I must have only previewed instead of submitting... ARGH!! This one might end up a little more scatter brained so bear with me. If this is a better fit in luthier's corner mods please move it.


    Last week I received my Carvin LB76 after months of waiting, the bass play absolutely fantastic and sounds great to boot, but there is one issue that I am having with it. I get these weird overtones/inharmonics (I don't know if that is the right word here) on the B string when I play in the second octave, anything less than the 12th fret sounds fine, the 12th and over have the issue. It sounds like a steel drum is getting beaten off key behind the note, it sounds awful. The issue exists even when the bass is unplugged.

    I have included a picture of the bass (you know the rules here, no pics no bass :D) as well as a sound sample of the issue so you can hear what I am referring to. On the sample I hit every string open and at every marked fret just to show the issue does not exist anywhere else. I get to the B string around :48 and I get over the 12th fret at around :52, you can hear the issue pretty clearly. I apologize for the fretbuzz, at the time of the recording I was testing out a high setup with tons of relief and was pressed for time recording.

    I did some reading and some people suggested the pick ups could be pulling the string off key, even affecting it acoustically. I have radiused pick ups so I thought this could be it. I lowered the pick ups extremely low but there was no difference in the issue. I did get the piezo bridge, I have no clue on the workings of these or if it could be the magnet in it causing the issue.

    Next I heard using a non-tapered string could help, so I swapped out the tapered B for a non-tapered B. I thought this made the issue slightly less pronounced but I don't know if it really was or if it was the placebo effect. I also attempted stringing through the bridge instead of the body but there was no change.

    I have attempted various setup styles to see if anything made a positive change, nothing really affected it, so I brought it back to the factory specs, which are pretty fast and pretty low.

    I am pretty much out of ideas, my only thought now is maybe it is due to the fact I had the bass made out of swamp ash. I wanted a light bass and I worry if it is having sympathetic vibrating causing the overtones. I doubt this is the first swamp ash LB76 in all the decades they made them. The only other swamp ash bass I have played was a Dingwall 6 string with a bolt on neck, the B sounded great.

    Since your going to ask, yes I have been touch with Carvin. I am currently in the process of sending the bass back to their head guitar tech. I am really hoping he can fix the issue because I truly love this bass, it plays spectacular. I was just wondering if anybody here maybe has any ideas/suggestions I can try to possibly avoid sending it away.
     

    Attached Files:

  2. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    The issue is not with fretbuzz at all. It is also not with intonation, neither of those are issues. I didn't make that clear, sorry.

    Listen to the clips, this rings out more from the body than the string.

    It happens acoustically but when plugged in the issue is amplified. The sound clip is just a line out from my head, it is amplified.

    Thanks and keep the help coming.
     
  3. 73jbass

    73jbass Supporting Member

    Apr 17, 2004
    Ellenwood,Ga.
    Either the string is twisted,or the pickup is too close to the string. Could be a few other factors also,but usually those are the first two to look at.
     
  4. JesusMetalFunk

    JesusMetalFunk

    Aug 11, 2011
    Does it happen without an amplifier? I am assuming its not the amp, but maybe just how it responds to that bass?
     
  5. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    I have made sure the string has a good witness point. I have also used 3 different strings. 1 tapered .130, 1 non-tapered .120, 1 non-tapered .130.

    The issue occurs with or without an amp, 1/4" plugged in or not. The issue is acoustic.
     
  6. Spring under the pickup/bridge? I can't see anything else which might be vibrating in that frequency range.

    Get a friend to touch stuff and see if the sound stops. Sometimes the strangest stuff can make noise.
     
  7. JLS

    JLS

    Sep 12, 2008
    Albuquerque, NM
    I setup & repair guitars & basses
    Thick strings don't sound real good, that high on the fingerboard.
     
  8. Ric5

    Ric5 Supporting Member

    Jan 29, 2008
    Colorado
    If the pickups get too close to the strings the magnetic field can create "false" harmonics that will make the string sound out of tune.
     
  9. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    The strings are currently close to the pickup to optimize volume, but I had tried lowering the pickups to about 4-5mm away from the strings. The issue still persisted.

    I use .130 on all of the other 6ers I have owned without ever experiencing this issue, I doubt string gauge has anything to do with it, especially since I used a .120 and it still had the issue, .120 is way to thin for a proper B.
     
  10. Dr. Love

    Dr. Love

    Nov 5, 2008
    Lubbock, TX
    I know you have tried a few different strings, but I had a weird "steel drum" resonance on my LB76 b string with DR longneck taper core strings too. When I switched to Lo riders, it went away. It still may be a string related issue.
     
  11. Okay if it's a part of your bass that is resonating you should be able to play the same note on a different string and hear the same overtone. Try playing the fourteenth fret on the A and see if it happens.
     
  12. Sheldon D.

    Sheldon D. Gold Supporting Member Commercial User

    Oct 3, 2001
    That's caused by audible harmonics being forced out of tune by the stiffness of the string. The shorter the harmonic, the more it's affected.

    IMO the ultimate solution requires a longer scale and a lighter string core. Not much you can do about scale length but you should be able to get pretty acceptable results with lighter core strings. LaBella makes the lightest core strings I know of. Give them a try.

    A couple more things to be aware of:

    Being too close to the magnets can affect things a bit but in your case you've ruled that out.

    With stepwound strings, excessive step past the saddle witness point will mess up the upper harmonics. We've found with our own strings it's best to keep it less than 1/2".
     
  13. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    Hey Sheldon, good to see this went around the world just to get advice from home. I had never even considered the scale, this is my first 34" 6 string, I didn't think it would be an issue.

    What do you mean by step wound strings? As in tapered?

    Where I am located it is impossible to any kind of odd ball string, such as La Bella's (maybe one flatwound 4 string set) and DRs MIGHT be available in a 4 string set, if your lucky and somebody ordered them and didn't pick them up. (You got something at the factory I could try Sheldon haha :D)

    I will be putting DR's on this bad boy when it does come back to me, but as it stands looks like this is going back to Carvin for a visit. This is best left to the pros, I'll see what kind of results they can get.

    Thanks again for all the help!
     
  14. Sheldon D.

    Sheldon D. Gold Supporting Member Commercial User

    Oct 3, 2001
    Step/tapered, same thing.

    It's a PIA shipping basses back and forth across the border. You're risking paying taxes on it's return trip up even if you've got all the proper documentation. We're extremely on top of our documentation and the brokers still mess up way too many times.

    If you want to try one of our Super J B-strings, I'll sell you one cheap and at least you'll know if it's the strings or the bass before you take things too far. Shoot me an email or call.
     
  15. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    Sheldon and the kind folks of Dingwall provided me with oodles of assistance and we took care of the issue as best possible.

    Thanks again to you all for help, and HUGE thanks to Sheldon and the guys at Dingwall!

    You can close the thread/delete it now if you want mods. I am satisfied.
     
  16. .
    Aren't you going to tell us what you/they ended up doing?

    How much better is it?

    Greg
     
  17. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    Nothing you can really do. We had balanced the pickups with a meter that reads the magnetic field, changed the B string to a Dingwall Super J B string which we thought made a slight improvement but were both unsure if it was again a placebo effect.

    The 34" scale just does not favour the B string was what I found out, and the issue is actually fairly common I am discovering.

    I don't use the B string really beyond the first octave, and it even if I do it sits fine in the mix, just not that grand solo. I love every thing else about the bass so this is not a deal breaker for me.

    Hope that clarifies it for you. I just got a set of DR Hi-Beams in so I am going to test those out later, see what kind of results I get.
     
  18. JustForSport

    JustForSport

    Nov 17, 2011
    Had the same issue on different basses.
    Finding the kind of strings that each one likes
    was the solution.
    Web Strings s/s rounds and s/s flats
    generally have very little of that effect.
    The B's sound really Big.
    Online order only, and inexpensive also.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.