changed strings now a reasonating buzz at the neck

KennyF
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Thu Jul 09, 2009 7:14 am

Okay... Perhaps some clarification of simple guitar geometry is in order here.

First off. I didn't see Neil's discussion on guitar setup, but I assume that he was speaking in general terms of basic guitar setup.

At any rate... In order to take some of the confusion out of this, let's look at the three critical elements (assuming that there are no structural problems with the guitar), which are straightness of the neck (truss rod adjustment), saddle or bridge height and nut slot height.

1) Truss Rod or straightness of the neck: The truss rod is nothing more than counter-tension to string tension. Meaning, the affect of string tension on a guitar, tends to pull the neck into a concave or "bow". The truss rod counteracts this tension by pulling against string tension in the opposite direction. A balance between the two must exist in order to keep the neck in the desired position, or achieve the desired neck relief. Neck relief is the allowable and/or desired amount of "concave or bow" in the neck.

Under normal conditions, barring any big swings in temperature or string gauge changes, the neck will probably not need adjustment. Guitar necks that are cut from a single piece of wood, like a mahogany neck on a Les Paul, are affected more by changes in climate than laminated necks, glued up from multiple pieces of wood.

2) Saddle or bridge height and nut slot height: In simple terms, the strings are held up by, resting on, bridging across, or laying on top of, the saddle on one end and the nut on the other.

2a. Nut slot height: There are a few different methods of checking nut slot height and I'll go into that later, but here's the goal. We are trying to place the string on the nut at a point above the fretboard where it's not too low or too high. If the string is too low, it will buzz against the frets. If the string is too high, you will end up bending the strings sharp when fretting first position notes or chords. High strings at the nut will also affect playability.

2b. Saddle or bridge height: The saddle or bridge height adjusts the overall action or string to fretboard feel of the guitar. This is a highly subjective thing. Some people like a higher action, and some people like a low action. However, there are limits. Higher action will produce crisper tone from the strings, whereas lower action will offer better, quicker playability. Lower action is typically dictated by the quality of the guitar itself, the condition of the neck, the condition of the frets, etc.

These are very simple explanations, but it's a start.

Now... Let's re-examine the original post in this topic.

1) The guitar played fine before the "string gauge change". That's significant!

2) No other problems were reported and no other changes were made to the "big three" mentioned above.

Note: If the nut slot height was right prior to string gauge change, it will remain that way after. Remember, the strings are sitting on top of the nut. They CANNOT be lower in the slot, unless the slot is filed lower. Think about it... The slot height is the distance from the top of the fret, to the bottom of the slot. This distance remains constant in our example, because the string gauge is smaller. If string gauge were larger, it's possible that the string diameter might be too large to seat properly in the nut slots, resulting in strings that are too high. Either way, we wouldn't be experiencing a buzz problem.

So... What are we left with?

The truss rod tension is probably greater than the new string gauge tension, resulting in back bow, causing fret buzz.

Solution?

Loosen the truss rod a quarter turn at a time until the buzz stops, or the desired neck relief is met.

OR...

Take it to your luthier. :laugh:


haoli25
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Thu Jul 09, 2009 11:27 am

Excellent contribution KENNYF.


KennyF
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Thu Jul 09, 2009 11:36 am

haoli25 wrote:
Excellent contribution KENNYF.
Thanks. B)


BigBear
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Thu Jul 09, 2009 2:14 pm

kennyf wrote:
haoli25 wrote:
Excellent contribution KENNYF.
Thanks. B)
Great job Bro!!! :)


KennyF
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Thu Jul 09, 2009 2:43 pm

BigBear wrote:
kennyf wrote:
haoli25 wrote:
Excellent contribution KENNYF.
Thanks. B)
Great job Bro!!! :)
Just tryin' to help out where I can. Image


quincy451
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Sat Jul 11, 2009 10:06 pm

When I talk about the buzz I am plucking a open low E string for example. I hear a buzz that appears to come from the top of the neck. But no fretting is happening in this test. If I fret a note anywhere on the string I get a buzz. This happens for strings 6,5,4 but not so much for 3,2,1. So G, B and the high E are not as much affected. Could be that I jost don't hear it.


quincy451
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Sat Jul 11, 2009 10:26 pm

Thanks for the well put post. So your thinking loosen the truss rod a quarter turn until it goes away.

Yes changing the strings was the only change. The instrument is new as of last November and bagged for most of that time. While the sound was good from the original strings, they where brutal for playability and very very bight so I went for the change.

No filing or other modifications where done. The one guestion I have about fret buzz is would get that on a open 6th string? I would think no fret is involved.

But I think you are 100% correct on the tension of these strings being less so the truss rod needs to be less tight to match it.

Thanks,
David


Chasplaya
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Sat Jul 11, 2009 11:38 pm

The following link will take you to Frets.Com a place that has heaps of advice and also clues to why your guitar may be buzzing. As none of us have seen your guitar we are really all just floundering around the many issues it could be. So really go to this site and by trial and error and process of elimination you may just get the answer before you mess around with Truss rod,

http://frets.com/FRETSPages/Luthier/Tec ... zlist.html


KennyF
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Sun Jul 12, 2009 4:36 am

quincy451 wrote:
Thanks for the well put post. So your thinking loosen the truss rod a quarter turn until it goes away.

David
David, Chas is right. It's kind of difficult to diagnose a guitar problem without having the guitar in hand, but yes, give the 1/4 turn back off a shot. Before you do, put a capo on the first fret and fret the low E on the 14th. Doing this will give you a straight reference line so that you can see where the neck is at. The low E should not be in contact with the 7th fret. Then, without removing the capo, back the truss rod off a 1/4 turn, put your finder back on the 14th and check it at the 7th again. A typical relief, or gap, between the fret and string is .010, or the thickness of a high 'e' string.


quincy451
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Sun Jul 12, 2009 2:56 pm

Yea I did the relief test. I got none...so I backed off the truss rod 3 1/4 turns loosening. It had enough relief for the high e string. So I stopped. But alas I will need more turns. The buzz is back on the low e string and the relief is back to unmeasureable. I will put some more turns on it later. But I think this is it, I just didn't give it good relief at the end of the first adjustment.

Thanks everyone
David


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