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I just completed a J45 style slope shoulder dread. It sounds good to me, except….
as I was fretting each half note up the FB, I noticed on the wound strings that the 7th and 8th frets produce the note, but they also produce a tinny, metallic noise. It is the worst on Low E, and hardly noticeable on each successive wound string at the same place (especially 8th). It sounds like a metallic rattle. I'm going to post a separate thread asking about it, but feel free to post any comments about this right here too. I put the truss rod in with no spline ala' Robbie O'Brien's course, and wonder if this could be related to a rattle. That would be the most mobile part of the truss rod, and the TR is still in neutral as the relief did not call for adjustment when I first strung it up. I may try to engage it a bit and see if that makes a difference. Since the noise seems most obvious at the frets, I wondered if it could be a wiggly fret, but they appear to be well-seated and level. When I play a barr chord at 7 or 8, I don't always hear it and it is much less noticeable. When I just push down on the string at each fret position, you get the typical "ghost" sound of the note (like a hammer-on) until you get to 7 and 8, and then it barely makes the sound of the note and you mostly hear the metallic sound. The note does play so it doesn't seem to be a dead spot.

I appreciate any suggestions or thoughts. Beth

So I tried Dennis K's trick of damping the strings, holding it at the nut and tapping the headstock and heard no rattling.
I very slightly engaged the TR and there was no change.

I doubt if this will help, but the last time I had an intermittent rattly guitar I'd forgotten to tighten the lower neck nut on the bolt. Also you might want to just check the tuners and everything else. Some things only seem to rattle at certain vibrations.

Assuming it is not a slightly high fret in front of 7 and 8 then depending on relief and string height at the nut it can be the portion of the string between the fret and nut that is causing the rattle. Try dampening that length of string and fret those notes again to see if it still occurs. I had a guitar that was about driving me nuts and that was the issue. It only happened with very specific pressure in 2 places but that was it.

Good luck!

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Thanks, Burton. How do you dampen that part of the string? And if that's the problem, do you just change the string?

Beth,

Just stick something under it, felt etc.. Really anything works, you just don't want it to be able to vibrate.

If it is the problem likely your nut slot is a bit too low on those strings.

When I am diagnosing something like this I try to really listen to exactly where the sound is coming from. It helps narrow it down.

Check that string balls are fully seated under the bridge too. Sometimes there is one note that makes them vibrate.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

My first guess would be the 9th or 10th fret is a little high, second guess would be what Burton suggests.
Another possibility would be a fret above the 9th or 10th, but that's pretty unlikely since it happens with a hammer-on.
The max excursion of the string happens in two places, where it is plucked and the distance from that point to the bridge below where it is fretted. If changing where you pluck the string makes any difference, that could give you a clue which of the higher frets could be causing the rattle. If something like that is occuring, it would not necessarily mean that the frets aren't level. Raising the action slightly should take care of it. How high is the action at the 12th fret on the low E?
I'd try putting a wedge shaped shim under the saddle to raise the low E about 0.01" or so, that should take care of it unless it's what Burton suggests.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

If it's the freted notes it's not the nut, although a too low nut can sometimes cause sympathetic vibration behind the fingered fret if the truss rod is JUST RIGHT, especially bass guitars.

I'm guessing the saddle is a hair too low on the low Eand the saddle doesn't match the radius of the fretboard so that the low E is closer to the frets than the rest of the strings. Check each string height individually.

Sometimes I hear that note on bad strings that have seperated from the core, usually DR brand strings. They're the worst.

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Old growth, shmold growth!

Thanks for the great ideas, guys. I'll check those things and if I figure it out, will post the findings here.

Another thing that I always have to check when I have buzzing on classical guitars is the frets near the apogee of the plucked string travel - near the center between the frets where the buzz occurs and the bridge. In your case it'll be in the 16 - 20 range somewhere. A high fret there will always cause a buzz.

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Waddy

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Sound Clips of most of my guitars

I did go right to the edge with the nut slots because I wanted it very comfortable to play, so it could be a bit low. I could not localize the noise when playing. I tried to cover the monitor hole because I thought it might be amplifying or confusing the location of the sound, but I couldn't tell.
Never thought about checking the seating of the string balls….


Lots of great ideas. Thanks!

Buzz Diagnosis:
http://www.frets.com/FretsPages/Luthier ... intro.html

I have a copy of this and appreciate the link. In my Newbie-ness, I may be mistaking terms, but this is more a rattle than a buzz (perhaps the two are interchangeable). And diagnosing it would I assume, follow the same path regardless of the term.

This could potentially be the by-product of a constant radius fretboard with a string taper. The higher the string taper...the higher the potential for buzzing on the outer strings in the fret 7 area....assuming you've set the action relatively consistently near fret 14. The smaller the radius on the fretboard the more potential problems due to this issue as well.

It stems from a non-linear relationship of the string to the fretboard surface when a string taper is used but a proper complex (compound) radius is not used.

I wouldn't presume to say that's what you'r dealing with....but it's something to consider.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Maybe it's how I level the frets, but that's not usually a problem for me unless I'm using a fretboard with an extreme taper such as a bass neck, or a radius smaller than a 9.5.
It is definitely worth considering though.

I level my frets with a straight file parallel to the direction of the string so any slight discrepancy due to the straight radius gets levelled out.

Some people level their frets with the same radius caul they use on the fretboard, and still others don't level at all if they've done a good job seating them.

I can see that last bit being problematic on a non-compound radius fretboard.

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Old growth, shmold growth!

This FB has a compound radius from 12 to 20" compliments of Andy at Birkonium.

I'm not sure you've eliminated the possibility of truss rod rattle. Hold the guitar at the upper bout, and rap on the back of the neck with your knuckles--like knocking on a door. If you have a truss rod rattle, you'll hear it plainly. Not every guitar that rattles when rapped will rattle when played, but the potential is there. If you want to know what it sounds like, loosely tape a saddle blank to the headstock and try rapping the neck. Once you know the sound, you'll start to here it when a guitar is set on the neck rest on your bench. If that's the problem, it can be cured by injecting something into the truss rod cavity. Some people use rubber cement. I use a silicone product. Padma suggested honey, but I think pine tar would be better (and give you a good grip on the neck as it oozed out).

Too much neck relief or a relief curve that's not ideal will often cause buzz/rattle in the middle of the fretboard. I'm not saying it's likely the cause, but it's definitely one of the first things I would check. Good luck; tracking down odd buzzes/rattles can be quite painful.

I've found that using a capo helps me to locate the source of any FB buzzes or rattles. I used to just use my fretting hand, but
it wasn't always a "sure thing". By sliding the capo up, starting at the 1st fret and playing a "G", I'm able to know precisely where
the problem lies.

Beth, what do you measure your neck relief to be?
I've just set-up my first guitars and got a bit confused with neck relief. In one source off the internet, the max neck relief was about .2 mm. In Cumpiano book he puts the max at about .7mm, massive difference. At .2mm I had metallic rattle in the same place as you. I increased relief to .4mm and everythings fine.

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We are all in the gutter but some of us are looking at guitars.

James and Joe - neck relief at the 7th was about 0.09" (a bit over the 0.2mm). I need to check it again though, because it's probably come up a bit under string tension.
Eric, I'll try the capo thing too.
Today's my day off so I'll be trying all of these ideas in effort to find that rattle! Thanks all!

Spent some time going through some of the ideas above. A few measurements:

Nut action - I set it at 0.015" and slowly tapering to 0.011" at the high E string when I slotted and now just checked the nut action again and it's significantly LOWER - all wound strings at 0.012"! How does that happen? I tried to be sure the strings were fully seated during slotting and measuring, but that must not have been the case. Even still, I'm reluctant to think the buzz is due to nut action as it happens when capo'd too.

Relief measured at the 7th fret = 0.007 and 0.004"

12 fret action is same at low and high E = 5/64"
I radiused the saddle against the end of the FB so it's radius should be about 20"
I confirmed appropriate tightness of the tuner nuts.
Rapped on the back of the neck and didn't hear a rattle.
Rocked all the frets. Found one tiny higher spot in the very center of the 12th fret, and barely a click over the 19th fret. Otherwise no rocking.
Here's a link to a short video of the string rattle doing hammer-ons. I was alone, so I couldn't video playing it, but you might get the idea.
https://app.box.com/s/tjtp68t8xan1mfl7ahgb

Thanks! Beth

Watched your video & wondered if you would get the rattle by hammer-ons placed between the strings, i.e., don't hit a string, just the fretboard. You might have to slacken a pair to stretch them apart enough to do this. This might eliminate all types of fret buzzing/rattling from the equation?

Maybe try raising the relief a little, only takes a minute and you can always put it back to what you have now.

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We are all in the gutter but some of us are looking at guitars.

That's actually sympathetic vibration of the string against the fretboard BEHIND the fretted finger, of the string being pressed down.
Under certain circumstances the string can vibrate on both sides of the finger.
Sometimes that happens when the nut slots are too low and you have just the right amount of relief so that the string is just barely above the fretboard behind the finger when pressed down.

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Old growth, shmold growth!