Troubleshooting a sympathetic buzz around C#

[CrankyChris]

I have a buzz that occurrs when I play a low C# and maybe sometimes a C (and sometimes maybe the 4th or 5th that note)

a.) it is a new (5 month old guitar) Martin M-36
b.) it is NOT fret buzz (it happens on the low E and A string at those notes) - and I can tell it's not fret buzz.
c.) I do have a K&K Trinity installed (so that would seem to be the likely culprit) BUT I have touched, moved, removed (except for the sensors), jiggled and held basically every component (wires and all) of that system inside the guitar and the buzz persisted. I have also had someone else look for the problem. They took everything out (except the sensors). That person was an idiot as it turned out but he couldn't find it either.
d.) It is not tuning mechanisms

The only things I can think of are: maybe loose binding or a rattling truss rod??? The sound seems to come from all over - it's strange. And I can't hold, squeeze, or bend it (gently) in any way to make the buzz stop.

Before I ship this off to an authorized Martin dealer, I wanted to see if anyone had any ideas on how to troubleshoot. ????

Here is a short clip
http://dl.dropbox.com/u/32257396/m36recordingBuzz.mp3

Thanks!

[wrench68]

I would make an audio recording of the noise and do spectral analysis of it to define exactly what it is you hear (or don't hear). I cannot emphsize strongly enough that mystery noises are often negative images, i.e., the problem does not cause a new noise that you hear; it prevents the voicing of normal sound, so you are left with a sound that is missing the expected components. For example, play a G note on the 6th string, then fret the note further and further from the fret until the G note becomes a hiss. Under spectral analysis, you will see that the hiss isn't a new component, but it's what is left after the components of a clean G note are no longer present. The hiss frequencies were there in both samples, but in the absence of a clean note, all you hear is the hiss. The reason it is important to understand this is to determine if the problem is one that adds a noise, such as rattling truss rod, or a problem that prevents normal voicing, such as a broken brace.

Depending on who does the troubleshooting, this information may be important to find the problem quickly.

[charles Tauber]

Originally Posted by CrankyChris

I have a buzz that occurrs when I play a low C# and maybe sometimes a C (and sometimes maybe the 4th or 5th that note)

There is an all-important word missing. Is that the 4th or 5th above that note?

b.) it is NOT fret buzz (it happens on the low E and A string at those notes) - and I can tell it's not fret buzz.

If it is occurring on three different strings but at the same fret, that suggests it is positional, rather than pitch-dependent. IF it is also happening a 4th or 5th above those notes, then it could be pitch-dependent.

d.) It is not tuning mechanisms

Have you also checked that the short portion of the string between the nut and the tuning pegs is not rattling?

Have you pressed down on the strings right at the nut, to ensure the strings are not rattling in the nut slots. If you put a capo on the first fret and then play the same pitches that rattled, does it still rattle?

maybe loose binding

It's pretty rare that binding will rattle/buzz.

or a rattling truss rod???

Have you tried tightening or loosening a bit the truss rod nut? Does that make it better, worse, neither? (adjusting the rod also changes the string height above the first fret, which may alleviate "back buzz" in which the "non-vibrating" portion of the string between your fretting finger and the nut is rattling on the lower frets.)

Without pictures or sound samples, if it is none of those things, I'd venture a loose brace (pitch-related) or loose fret (position-related). To check for a loose brace, if you can't seem to find any origin from which the buzz emanates, press gently on the top in lots of different places. If doing so stops or diminishes the buzz, likely a loose brace.

To check for a loose fret, use the erase end of a pencil and press downward on the fret while playing the buzzing note. If it gets better, it's a loose fret.

[CrankyChris]

Originally Posted by charles Tauber

There is an all-important word missing. Is that the 4th or 5th above that note?

---I'd have to check - but it's definitely on lower notes only

If it is occurring on three different strings but at the same fret, that suggests it is positional, rather than pitch-dependent. IF it is also happening a 4th or 5th above those notes, then it could be pitch-dependent.

--- Not at same fret - it's pitch related. The same thing happens on the 9th fret (or whatever fret c# is ) on the E string and the 4th fret on the A string. Same buzz.

Have you also checked that the short portion of the string between the nut and the tuning pegs is not rattling?

---Probably, but I'll double check when I can.

Have you pressed down on the strings right at the nut, to ensure the strings are not rattling in the nut slots. If you put a capo on the first fret and then play the same pitches that rattled, does it still rattle?

-- yes to pressing down
-- regardless of capo position, it's the pitch.


It's pretty rare that binding will rattle/buzz.


Have you tried tightening or loosening a bit the truss rod nut? Does that make it better, worse, neither? (adjusting the rod also changes the string height above the first fret, which may alleviate "back buzz" in which the "non-vibrating" portion of the string between your fretting finger and the nut is rattling on the lower frets.)

-- I haven't done that - but I don't know if I have the appropriate tools. I don't know if I can get to the nut at the truss rod. And why don't they come with truss rod adjustment wrenches btw?


Without pictures or sound samples, if it is none of those things, I'd venture a loose brace (pitch-related) or loose fret (position-related). To check for a loose brace, if you can't seem to find any origin from which the buzz emanates, press gently on the top in lots of different places. If doing so stops or diminishes the buzz, likely a loose brace.

-- I've stuck my hand up in there and been unable to make a difference regardless of what I touch. I'll post sound samples as soon as I can - check back this evening.

To check for a loose fret, use the erase end of a pencil and press downward on the fret while playing the buzzing note. If it gets better, it's a loose fret.

Thanks for your input!

[CrankyChris]

I'll get some clips this evening

[charles Tauber]

Okay, you've determined that it is pitch-related. That could mean either a "mechanical" or "acoustic" sympathetic vibration. By "mechanical", I mean a lose brace, ball ends of the string not seated and vibrating against the bridge plate, loose nuts/bolts, if bolt-on neck, truss rod nut loose, pick-up components - though you've looked at those ...

By "acoustic", I mean the way "the system" as a whole vibrates. Things like wolf notes. Has this 5-month-old guitar always had this buzz or developed recently?

[CrankyChris]

Originally Posted by charles Tauber

Okay, you've determined that it is pitch-related. That could mean either a "mechanical" or "acoustic" sympathetic vibration. By "mechanical", I mean a lose brace, ball ends of the string not seated and vibrating against the bridge plate, loose nuts/bolts, if bolt-on neck, truss rod nut loose, pick-up components - though you've looked at those ...

By "acoustic", I mean the way "the system" as a whole vibrates. Things like wolf notes. Has this 5-month-old guitar always had this buzz or developed recently?

I know what you mean by "the system". I've always felt that the low G (3rd fret on low e string) has a sort of dead response ( I suppose that's a wolf note) . It thuds rather than rings.

I didn't notice the buzz in the shop (nor the wolf note g), but I noticed it within weeks of having it new. I did notice in the shop that it's low end response was somewhat lacking (compared to dreads that I normally play - but I thought that was just part of the deal with the smaller 0000 body). I play a lot of capo'd material (up to the 5 or even 8th fret) and that's where it really shines.

It's kind of subtle and it could be mistaken for fret buzz/sloppy playing. I believe it has always had it. Although, I had the pickup installed almost immediately after I purchased it ....so.....??? I don't know if it was always that way or if the pickup installation is related. If I HAD to guess, I'd say it more than likely appeared after the installation of the pickup.

[CrankyChris]

Updated: Here is a short clip

http://dl.dropbox.com/u/32257396/m36recordingBuzz.mp3

It seems to be several notes from...say a# to maybe d (as I play it right now).

[tadol]

You didn't mention, but have you tried other strings, and maybe a slightly heavier (or lighter) gauge to see if you still hear it?

[CrankyChris]

Originally Posted by tadol

You didn't mention, but have you tried other strings, and maybe a slightly heavier (or lighter) gauge to see if you still hear it?

I have tuned down 1/2 step and I don't think I noticed it then. I think I've always had the same guage of string b/c Martin doesn't reccomend putting anything thicker than lights on the m-36.

[tadol]

Most builders recommend lights, but most guitars will handle mediums as long as you pay attention. I'd try another brand, maybe some med lights ( light meds?) or a bluegrass set, just to see if you still notice it.

[wrench68]

Is the sound clip in standard tuning? Is that a normal G chord at 4.6 seconds? In any part of the sound clip, did you play F# at the second fret of the first string?

[CrankyChris]

Originally Posted by wrench68

Is the sound clip in standard tuning? Is that a normal G chord at 4.6 seconds? In any part of the sound clip, did you play F# at the second fret of the first string?

It is a G chord shape (with the 3rd fret fretted on the b string) , but it's capo'd up several frets. So the single note (with the buzzing following that) is probably C or C#.

--actually checked--

Actually (I've checked my on-line piano and) it's a B. So I'm capo'd on the 4th fret and I'm playing a G shape chord - which is actually a B chord. So the individual buzzing is on B in this example. As I mentioned a few post ago - I went home and I could hear the buzz over a range of notes - but there was no buzz below (approximately) an A# or above a (approximately) D.

[wrench68]

Originally Posted by CrankyChris

It is a G chord shape (with the 3rd fret fretted on the b string) , but it's capo'd up several frets. So the single note (with the buzzing following that) is probably C or C#.

--actually checked--

Actually (I've checked my on-line piano and) it's a B. So I'm capo'd on the 4th fret and I'm playing a G shape chord - which is actually a B chord. So the individual buzzing is on B in this example. As I mentioned a few post ago - I went home and I could hear the buzz over a range of notes - but there was no buzz below (approximately) an A# or above a (approximately) D.

Yep, B. At every B in the clip, there is a very strong F#. That makes sense on your G chord capoed at 4 because the second string is playing F# there. But the single B note you played from 8 to 12 seconds is also accompanied by a very strong F#4, followed by a decay period with a beat frequency of about 12 Hz. This also occurred on your G chord. I think that beat is the buzz you hear. I think it is coming from a clash between the F#4 overtone at 372 Hz and a 120 Hz natural resonance. Your comment that the problem goes away when tuned down supports this, but to determine with more certainty if this is the problem, some more audio sampling and some tap tone recordings are necessary. If running through Charles Tauber's checklist (man, I love that guy's ability to articulate tech to the rest of the world) doesn't find some other cause, the buzz is possibly a clash of body resonances and played notes, possibly caused by the additional mass of the pickup, as you suggested, and it may be correctable with another small mass adjustment.

Do you have any recordings of the guitar before the K&K was installed?

[CrankyChris]

Originally Posted by wrench68

Yep, B. At every B in the clip, there is a very strong F#. That makes sense on your G chord capoed at 4 because the second string is playing F# there. But the single B note you played from 8 to 12 seconds is also accompanied by a very strong F#4, followed by a decay period with a beat frequency of about 12 Hz. This also occurred on your G chord. I think that beat is the buzz you hear. I think it is coming from a clash between the F#4 overtone at 372 Hz and a 120 Hz natural resonance. Your comment that the problem goes away when tuned down supports this, but to determine with more certainty if this is the problem, some more audio sampling and some tap tone recordings are necessary. If running through Charles Tauber's checklist (man, I love that guy's ability to articulate tech to the rest of the world) doesn't find some other cause, the buzz is possibly a clash of body resonances and played notes, possibly caused by the additional mass of the pickup, as you suggested, and it may be correctable with another small mass adjustment.

Do you have any recordings of the guitar before the K&K was installed?

Unfortunately no.

But what you say makes a lot of sense, though.

What does this mean "some tap tone recordings are necessary"? How does one do that?

And how might I experiment with adding subtracting mass?