Un-identifiable Buzz

[Joe Mendel]

I have a home made F-5 mandolin in for repair because of a buzz, it was probably made in the 70's and in spite of being a little weird it sounds good and plays well. The buzz is sort of a metallic, resonator-ish sound, on the D & G strings, less so on the A & E. It does it all the time, open or fretted. I've eliminated the truss rod, nut, frets, strings, tuners, bridge & tailpiece as sources. There was some loose binding, but that's been reglued with no change. The best I can tell it's coming from somewhere in or on the body, but grabbing, pressing, squeezing, etc., anywhere I can touch doesn't change the buzz. I really do not think it's coming from anywhere on the neck. I can't find any loose joints, or cracks inside or outside of it. I'm out of places to look. I'm wondering if it's been there since it was built and the current owner just noticed it, he hasn't had it very long, or maybe a temperature or humidity change has caused it. It's not horrible and from a few feet away it's not really bad, but you can definitely hear it when you play it. I imagine a microphone would pick it up very well & owner plays out a lot. It sounds like two surfaces are just close enough to buzz off of each other, like a glue joint that has gaps in the glue. Any suggetions?
Thanks.

[MikeEdgerton]

You might start with Frank Ford's Buzz Diagnosis (http://www.frets.com/FRETSPages/Luthier/Technique/Setup/BuzzDiagnosis/buzzintro.html) page on www.frets.com (http://www.frets.com).

[Steve Davis]

Loose pick guard screw?

[sunburst]

Grabbing and squeezing should have found it, but possibly a loose or cracked tone bar.
Check the clearance of the strings between the nut and the tuner shafts. If any of them touch one another, a tuner shaft, the string windings around a tuner shaft, or anything else between the nut and the tuner they can buzz.
I assume you've tried other sets of strings, and how did you eliminate the truss rod as the buzz source?

[Joe Mendel]

Mike, I check Frank's site frequently, but I didn't find the answer there this time.
Steve, no pickguard, never was. Good try though.
John, maybe I should have said I have done my best to eliminate the truss rod. I've adjusted it several times, from tight to very loose with stops in between, I've pushed & pulled & twisted on the neck. The buzz never changes. When I hold the mandolin up to my ear the buzz is much louder around the body than the neck. I've tried a three new sets of strings. The headstock is strange, it is sort of really wide snake head, with A-style tuners & a narrow scroll at the top, the strings don't touch each other or posts other than the one they are connected to. In fact the strings are really far apart over the headstock.
The center seams on the top and back are excellent inside and out, the neck joint is solid, the blocks look fine, the tone bars are not visibly cracked or loose and are well fit to the top, it is not a bolt on neck.

[sunburst]

Well, that's about everything, it can't be buzzing...(yeah, right)
Good luck, and if you figure it out be sure to let us know what it turnes out to be.

[man dough nollij]

Seems like somebody else had this mysterious problem recently, and it turned out to be an invisibly cracked bridge...:confused:

[Michael Lewis]

Joe, can you tap on the instrument with a knuckle? A knuckle is just hard enough, soft enough, and heavy enough to be a pretty good "hammer" for such investigations. I usually go all around the edges of fiddles and basses in this manner to find if there are any loose seams. Loose seams sound different than solid ones as you well know. Closed cracks can be nearly invisible and still buzz, so look closely. Low angle reflected light is a real help to see these some times.

Maybe strip all the hardware off the instrument and tap and probe until you find something. Loose fingerboard? Flex and tap, flex and look in low angle reflections.

"Hammers" of differing weights can be very useful because they make different frequencies. One of my lightest hammers is the back of a fingernail, Just flex your finger and let the smooth back of the nail hit the surface to produce the impact. Another good fairly light "hammer" is a wine cork on a bamboo skewer. Heavier "hammers" should only be tapped on areas that are strong enough to sustain the impact and not cause damage. Leave no marks.

By all means, when you find the offending buzz let us know. We can all learn from this event.

[latentaudio]

Can you record the buzz and post it somewhere? I had a sound similar to what you describe on a archtop guitar and it turned out to be some of the wiring just grazing the bottom of the top.

[lenf12]

Have you looked inside with an inspection mirror? Maybe a loose tone bar or kerfing that you can move around with something. Have you eliminated a cracked bridge as the cause? Are the string slots in the bridge too big allowing the strings to move around when struck? That's about all I can think of. Let us know.

Len B.
Clearwater, FL

[Joe Mendel]

I'm still hunting for the source of the buzz, as soon as I find it I will report back. Thanks for all of the suggestions, I'm going to try them all again. Probably tomorrow, I've had enough for today.
Thanks again.

[rockies]

Buzzes drive repairmen crazy, especially if they disappear for no reason. It sounds like yours is steady so a little device I have luck with (sometimes) is a auto mechanics stethoscope (inexpensive at an auto parts supplier) Holding the probe and working from headstock to tail while plucking the offending string at the same time the buzz will get louder as you get closer to the loose or cracked part. Borrow one from the friend who repairs his old car.
Rockies

[Lee Callicutt]

I've been working at a setup on a cheapie recently where I stepped up from J-62's to J-74's. I fitted the bridge, tweaked the nut, etc. Everything was hunky dory for a month or so of playing around on it with the heavier strings and then all of a sudden one day a nasty, buzzing rattle appeared when I would aggressively play open harmonics at the twelth fret on the G and D courses. At first I told myself it was just heavy-handed technique on my part, but instead of going away it got worse with each passing day -- to the point that I was really worried I had developed a loose or cracked tone bar from the heavier strings.

I went through a sequence of playing the open harmonics to produce the buzz, which by now was pretty much guaranteed to show itself despite my hopes, let it resonate and try to see if I could dampen or suppress it by pressing on the top, or bridge in any area, but no luck.

So, after eliminating the easy suspects -- removing pickguard, tailpiece cover, truss-rod cover and doing a mirror inspection of the interior -- I started the exploratory knuckle rapping. I was relieved to find no buzzes in the vicinity of the tone bars, but found that with fairly hard rapping on the body, I could produce the faintest metallic "ping" as I got closer to the neck joint. Strangely enough, there was no corresponding rattle when I rapped on the back of the neck, but I tweaked the truss rod a bit anyway, hoped for the best result, and "voila!" it turned out to be the truss rod after all. I'm thinking the heavier strings were just enough change to make it rattle inside the neck and show it's evil sonic nature.

Best of luck. I hope yours turns out to be something so simple.

[Stephanie Reiser]

Oh boy, buzzes can really be mysterious.
I have one in the shop right now that buzzes only when C# is played on the A or E strings. C natural or D or any other note does not buzz. No buzzing, however, with C# on the G's. I had a second person pluck the strings while I fretted the note with one hand and used my other hand to try and "muffle" any vibration suspects, including string ends. So far I haven't found the reason for the buzz, but my next step will be new strings, and one string at a time I will recheck that buzz. It definitely comes from the headstock, so I am convinced that it is a string end vibrating at just that C# note, or maybe a tuner post......

[Big Joe]

I forgot to mention one thing. On some mandolins Elixer strings will cause a rattle on the G strings. Just changing to a different brand will rid the rattle...buzz...noise...and life is good again :) . It is amazing how something so small and simple can be so problematic!

[Joe Mendel]

Here's what I've done since my last post: Reshape & reslot the top of the saddle, poured superglue on the saddle & looked for wicking-there was none, the bridge posts were slightly loose so they got a drop of superglue, also. I reshaped the top of the nut and tweaked the slots (again), added washers to the truss rod & adjusted it several times, including a little tighter than I was comfortable with. The tailpiece is packed with leather over and under all the strings, I ran superglue along the frets on both sides, found another piece of loose binding & reglued it. More new strings, with leather threaded through behind the bridge and nut, I have also tightened every screw & examined the inside with light & a mirror, several more times.
With the strings muted the whole length, I've tapped on the body & neck with a small hammer. The buzz is still there, I can't hear it when tapping the neck, but anywhere on the body I can hear it. And, of course when picking the strings.
The customer doesn't what to put a lot of money into it, so he doesn't want to take the back off, and doesn't want to drill through the FB dots & glue the truss rod in place. I can't say I blame him for that, I'm not convinced it's the truss rod and I'd hate to do that and not cure the problem.
Thanks for all the suggestions, if you have any more ideas, please post them.

[sunburst]

Your diagnostics point away from the truss rod, but rather than glue it in place if it were buzzing you can take out the inlays and drill little holes and drive dowels down against the rod to (hopefully) silence it and still have it functional. Glue the dowels in place and replace the inlays.

Something's loose somewhere, hope you find it.

[Joe Mendel]

That's a great idea, John. I'll talk to Ray (the owner) & see if he would like me to try it. I hope he does, I would love to see if that is the cause after all. If that doesn't cure it I'm sure that will be the end of the project, he doesn't want to spend more than it is worth to fix it.

[Luthier]

Its Gremlins...Gremlins I tell ya:whistling:
Don

[Kerry Krishna]

I had the same thing as this happen about a decade ago on a guitar. It drove me (and three other repair guys) nuts untill we figured it out.The dowel thing John mentioned solved the problem. The buzz on this axe was also WAY louder in the body than the fretboard. Also. Rockie's suggestion about the stethiscope is gold. There is no substitute for the right tool in the right circumstance...Kerry K

[Stephanie Reiser]

Joe, you said that you've eliminated the neck and headstock, that the buzz is somewhere in the body area. I would revisit the tailpiece and the TP cover, if it has one.
As for the buzz that I was looking for, the one at C# only, turned out that just a change of strings solved it. Must have been a harmonic vibration from a string end. Duhhhhh........

[Joe Mendel]

I finally got the OK from the customer to do John's dowel trick. Unfortunately, it didn't solve the mystery buzz and the customer doesn't want to put any more money into it. If it were mine I probably would have stopped before now, so I can't blame him for not wanting to. He did end up with properly seated, crowned & leveled frets, & properly cut nut slots & some new dots in the FB, & the bridge is now fitted correctly to the top. This one will remain a mystery.

[Tom C]

The buzz is sort of a metallic, resonator-ish sound

Still sounds like a slight string/fret buzz. I get that sound on my mandobanjo on the first fret on E string when I play it open.

[bryce]

With uncoated strings you can use an ohm meter to check for very slight fret contact. Hook one lead to the offending string behind the bridge, probe different frets with the other lead while picking. It helps to have an extra set of hands. If you have to do this by yourself, use a capo on each fret to free up that hand .Make sure the fret lead doesn't touch any strings. If its buzzing on a fret the needle will move. Sometimes very, very, very slightly so check each fret several times with 5-6 pick strokes. It has worked for me from time to time. David

[Jan Ellefsen]

This problem can be the piano tuners nightmare, with hundreds of parts that may cause the problem. And sometimes you may find that the buzz is coming from a picture on the wall or some object on a shelf resonating with one note.

[WireBoy]

great timing on this topic. My F5 style has just recently developed a similar frequency specific buzz. mine shows up on the D strings, open and about the first 4 frets. loudest on the 2nd fret. pick the D string(s) softly, its OK. dig in with the pick stroke and it rears up. it was fine until a few weeks ago.

i had just changed my strings a few days before. i used the same string type on the change. then the buzzing starts. my efforts so far. i damped EAG strings. i changed the D strings (to a different type, even!) checked the nut, tailpiece, damped the strings tween the nut/tuners, bridge/tailpiece. felt/pressed/squeezed the top to find loose tone bars. no pickguard. tuner screws/buttons/bushings are tight. no loose string ends. no internal pickup wires.

i have yet to use an inspection mirror to peek thru the f holes. or check the truss rod for loose adjust nut or sloppy tension. i'll try those tonight.

the other solutions mentioned here are luthier level operations. i think i need to send my buzzy bee out for fixin' Can anyone recommend a repair man/gal who would be willing to take on a sleuthing project like this? i live in Los Angeles and mando luthiers don't seem to be in great supply around here.

[mandozilla]

Hey Wireboy, I too live in the LA area and need to find a good mandolin set up man. I'm thinking of sending mine to Steve Perry in Tennessee for a thorough set up and a Mandovoodoo treatment after the holidays. Anyhow, I hope we get some info on LA area luthiers on this thread. :)