An unusual string buzz

[Craig Bumgarner]

I'm getting a buzz on the D string when playing rhythm chords (with a pick) which involve fretting the 7th fret, such as 7X67XX. When each string is isolated, but the chord shape maintained, picking the A note on the D string induces the buzz. BUT, if I play that note without the chord shape, i.e. all other strings open, no buzz.

I think the buzz is actually coming from the low E string and that portion of the string between the zero and 7th fret. Or, at least, if I dampen this section of the low E string, the buzz goes away. My take is that playing the A note on the D string while fretting the B on the E string is stimulating a vibration on the portion of string between the 0 and 7th and that portion is kissing a fret somewhere.

So, what to do? Frets are true, minimum relief in neck, no truss rod. Adjusting action height has no effect. (steel string, 6 string, Selmer style with a floating bridge, tail piece and zero fret.

[Mark Swanson]

My guess is it's probably the section of string that lies between the fretted note and the nut vibrating against the frets. You'll need to slightly change the relief, a little more is the best bet I'd say. You might stop the noise with even less relief but it would be possible for the vibration to still be there, so loosening the rod rather than tightening just a little might get rid of it best.
Let me know if I was right!

[Craig Bumgarner]

Mark: Thanks, good idea, but this one has no truss rod, just a fairly thick neck and two carbon rods. I measure about 3-4 thousandths with a machined straight edge and feeler gauges from the 2nd to the 9th fret. Interestingly, I just noticed the 7th fret is about .002" higher than the surrounding frets. Could this be the problem?

What is the theory on strings btwn the nut and the point where fretted? Is the inactive part of the string supposed to be down on the lower frets so the string is fully dampened out or are they supposed to be completely free of the frets, like the active portion of the string? My guess is the former, but I've never really heard this discussed.

[Mark Swanson]

What is the theory on strings btwn the nut and the point where fretted? Is the inactive part of the string supposed to be down on the lower frets so the string is fully dampened out or are they supposed to be completely free of the frets, like the active portion of the string?

That depends on the players' preference. for example, the nut height and the amount of relief can be set to the players' preference, and little or no relief may have the strings resting on the frets when measured behind the fretting finger, or another guitar might have enough relief to keep the string free of the fret tops.
And some guitars have just the right amount to allow a sympathetic buzz on some notes.

[Rick Davis]

Um, don't want to seem argumentative but I respectfully disagree with the notion that relief is optional. It's not, it's essential. The neck must have a consistent slight curve from the nut to the body in order to function well and allow the best action. A neck with too little relief will have to have a high nut and high action over the upper frets and it'll still develop strange, annoying whines and buzzes as the strings vibrate against the frets between the nut and fretted note. Too much relief means high action in the middle of the 'board and likely fret buzzes above the body.

I'll go a step further and say that building a steel-string guitar without an adjustable truss rod is a disservice to whoever ends up with the instrument. As a professional builder and repair tech, when I have a set-up to do, the truss rod wrench is the first tool I reach for: everything else follows setting relief. It's basic, not an afterthought.

And yes, you're right -- it hasn't been written about properly. The information is buried in Cumpiano but most writers have overlooked it. I suspect that's because most writers are builders and builders are notoriously bad at fret work and set-up!

[Al Dodson]

I had the same trouble in exactly the same place (B -7) on my Mac which is also sans truss rod. It has diminished over the years but every time I augment (change) the strings it comes back a little. If I remember correctly, I identified which fret was buzzing (2nd?) and cut that fret down under the E string a little bit. I'm betting your whole guitar is quiet resonate. Sorry for the bad pun.

[Craig Bumgarner]

Um, don't want to seem argumentative but I respectfully disagree with the notion that relief is optional. It's not, it's essential. The neck must have a consistent slight curve from the nut to the body in order to function well and allow the best action. A neck with too little relief will have to have a high nut and high action over the upper frets and it'll still develop strange, annoying whines and buzzes as the strings vibrate against the frets between the nut and fretted note. Too much relief means high action in the middle of the 'board and likely fret buzzes above the body.

Makes sense.

I'll go a step further and say that building a steel-string guitar without an adjustable truss rod is a disservice to whoever ends up with the instrument. As a professional builder and repair tech, when I have a set-up to do, the truss rod wrench is the first tool I reach for: everything else follows setting relief. It's basic, not an afterthought.

I've been coming around to that conclusion as well. I've been copying 60-70 year old guitars that did not use truss rods and was thinking if it was good enough for them, its good enough for me. But other than the added weight, I'm thinking that is pretty much just being old fashioned for old fashioned sake.

And yes, you're right -- it hasn't been written about properly. The information is buried in Cumpiano but most writers have overlooked it. I suspect that's because most writers are builders and builders are notoriously bad at fret work and set-up!

Guilty as charged. Any recommendations as to a book that covers fret work and set-up really well?

Al: Thanks for your thoughts. New strings do seem to make the buzz worse, which suggests different brand ore gauge of stings might help. I lowered the action some, something I was planning on doing anyway and surprisingly, this seems to have cleared up most of the problem. I can live with what remains for now. Rick's comments about truss rods sound right on to me as do his comments about better setup. All I need to do now is find 100 grams to remove elsewhere and a good book on setup.

[Alan Carruth]

I'm going to disagree slightly with Rick: relief is usually desirable, but not always. Many jazz players I know don't want any relief, since it tends to make the intonation worse and also makes the action higher in the middle of the neck. Yes, it reduces the available dynamic range, but if you don't need it there are benefits to using no relief. As the Brits say; it's a matter of horses for courses...

I do agree that making a steel string neck without an adjustable truss rod is a bad idea. I'd love to use them in classical necks but they tend to weigh too much. One of my students made himself a couple of titanium truss rods for his classicals, and they were great.

Alan Carruth / Luthier

[Craig Bumgarner]

Rick and Alan,

Do you use single or double truss rods? In my case, where it is suggested I introduce more relief, I guess I would need to the double or build the neck less stiff to start with. I've seen some single titanium truss rods for sale, about $40.

CB

[Mark Swanson]

Thanks Al, your post helps explain my experience also. I have a light touch when I play and I can get away with minimal relief but other players have other circumstances.
My favorite trussrods are the ones sold by Allied.

[Ron Belanger]

One of my best purchases early on was Dan Erliwine's Videos and book on fretting. It was well worth the investment. I initially purchased it for refrets, but everything he says and does relates to new builds as well. If you plan to continue building and / or repairing, I highly recommend them.

[Michael Lewis]

Good set up work comes from knowledge of the physical forces involved and experience. You can read up on the first but you will have to spend some time on the rest of it. Rick is right, start with setting the relief, assuming the frets are all even (big assumption, and you may have to do some work here to proceed to the next step). 2nd thing is to set the string height in the nut, and finally setting the action by adjusting the saddle. This is the basic overall perspective and you will be able to make finer and finer settings as your experience grows. Doing lots of set ups on cheap instruments is a great education, especially if you treat each one as a prized vintage instrument. I know this may not sound worthwhile but your customers will certainly appreciate your approach.

[Alan Carruth]

I've been using the Allied rods as well: I like the 'geared' aspect. Not everybody knows about them as yet. I had one store tell me that I needed to reset the neck on a guitar that only needed a truss rod adjustment. They took a turn on the rod and the neck didn't move as much as they thought it should have.

Alan Carruth / Luthier

[Pat Foster]

A bit OT, but I love the Allied rods. The threads on each end are of different pitches, so the effective pitch is the difference between the two. The result is a pitch so fine that if that pitch were to be cut into the rod, it would be such a fine thread as to be unable to stand up to the stresses involved. Ingenious.

Pat

[Craig Bumgarner]

I think I have an Allied rod that was sent to me out of the blue, no charge, a couple years ago. It has been sitting in a drawer ever since. I'll put it to work on the next build. I wish they did not weigh a quarter of a pound. I gotta shave a lot off the braces to make up for that!

[Mark Swanson]

That might not be an Allied rod- they are the smallest and lightest of all the rods out there.

[Craig Bumgarner]

I thought it was Allied, but I could be wrong, it was a good while ago. The only other source I can imagine is LMI. Their double acting rods look very similar and Allied makes a reference in having developed their rod while working at LMI, or something to that effect. Allied says their rods are made in China, LMI says theirs are made in the US.

I distinctly remember it was a west coast company and at the time was surprised by the no strings attached nature. They just sent me this truss rod out of the blue, saying have a look at this.

I had a look at the Allied truss web page a minute ago. It is the only truss rod page I can find on the site.

http://www.alliedlutherie.com/truss_rods.htm

What I see looks very much like what I have. 1/4" x 3/8". Mine is configured and shaped like theirs, has the stainless rectangular top bar, shrink wrap covered lower round rod bar with threaded ends. Even has the darker gray end piece (unchromed I believe, where the rest is) on the end of the TR that does not have the barrel nut. It does NOT seem to have any special gear ratio as described by others earlier in this thread. With one end clamped in a vise, one full turn puts about 3/8" of bow in the rod, either direction. There is no mention of this in the web page, so maybe I'm looking at the wrong thing.

The rod I have weighs 117 grams, a little over a 1/4 pound. Allied does not mention a weight, at least not that I noticed.

BUT, I very interested in finding a lighter double acting rod, so please tell me where to look.

Craig

[Mark Swanson]

Hmmm, I never did weigh one of them but they do seem smaller and lighter than anything I had before. The Stew-Mac Hot Rod is a lot bigger and heavier and the Martin rods are big too.
As far as the threads go, you should be able to look at the treads on each end and plainly see they are different. if they aren't, then you don't have one.

[Chuck Tweedy]

Or if there are threads only on one end, then you do not have one of the Allied rods.

[Craig Bumgarner]

Or if there are threads only on one end, then you do not have one of the Allied rods.

Threads at both ends, one LH, one RH, the "look" to be the same pitch. Here is a picture of the truss rod I have: