classical string buzz

[Peter Laine]

 I have a buzz problem with a fairly nice little classical guitar, a Takamine C-132S  The owner,who plays for a living, and who prefers very low actions, was getting string buzz on the A & D strings at the 3rd 4th & fifth frets. I checked with for high frets found some at the fifth & sixth, filed them down tuned up and still had buzz.  Removed strings, flattened the entire fretboard, re-crowned & polished and,   still had this buzz.   This guitar has a truss rod and I played with that a bit (loosened)and could not get rid of the buzz.  At this point I noticed that the fret board actually had a bit of radius in it but the saddle was flat, so I made a new saddle with the highest point of the chord at the A & D string positions, I left it a bit high overall to begin and I believe I had it fixed.   Problem was that the saddle height was now 15 mm at the D string and the top was raising below, and sinking above, the bridge, I was a bit leery of leaving it like that so I lowered the entire saddle so the high point was now 13.5mm, reset the truss rod, brought the action at the 12th to 3.75 (+ -) and when I played it the buzz was gone, or so I thought. the owner plucked a bit harder than I did to test and he still gets buzz, now  only on the D string, still at the 3rd,4th, & fifth fret.

Now to solicit the advice, I'm afraid of raising the saddle any more, I'd have to get back to around 15mm off the top to achieve buzz kill, and this top seems very lightly constructed.  the only other option I can think of  to try is to remove fretsand hollow the fingerboard between 3rd or 4th and 10th o r11th, on the bass side

any sagacious fellows have insight on this? 

By the way how does one pronounce Takimine? Talk-a-mee-nee, or Tak-a-mine

[Jeff Highland]

Assuming you have done a good job on levelling the fretboard, firstly and in this order

-Stop "playing" with the truss rod. Set the relief with it to 10-15 thousands of an inch and move on

-Now check the nut slot heights and adjust if necessary

-Now check each individual string height at the 12th fret. Standard classical is graduated from 3mm at the high e to 4mm at the low E, but D may require a bit more  because it is quite flexible.

-Adjust the saddle appropriately. It will need to be the height it needs to be regardless of whether that is good for the top

[Peter Laine]

 First ,thanks for answering.   I really do need some info on this , I need to get this guitar back to him asap and he really is not happy with the buzz ( though I don't notice it when I play nor does one other very good player I asked, different styles )

to discuss your points

some times when a guitar really needs a neck reset but the owner either can't or won't,   you can get a kind of temp fix by either over cranking the truss rod and removing all neck relief, or lowering the saddle. If the action is truly high you don't need the neck relief anyway.  I don't like doing either especially lowering the saddle.   I feel you loose too much leverage and thus amplitude in driving the top.

Is the proper neck relief for a classical 10-15 thousands? I default to .006 on a steel string. embarrassed to say that with the generally  higher action, and the usual lack of truss rods I have not paid much attention to it in classical's

I don't think the nut slots are at issue I looked back at my text and see that I didn't mention that it is the fretted notes at the 3rd, 4th & 5th that buzz, not the  open.

The saddle  height at the offending D string is 13.5mm.   with the action, at least, in the range I believe that you recommend,  of 3.75,

  Are you saying that I should make the saddle height conform to the neck?  on steel strings I  hold the view, (rightly or wrongly), that the  saddle  should be set at a target height , once again to optimally drive the top, and then make the neck angle conform to that.

   My main question I suppose got lost in the clutter, to whit: what is the maximum safe saddle height on a classical.

I read one article showing a graph of saddle heights vs measured top amplitude from 10 to 20 mm claiming that 15-20mm will cause separation of the bridge, 15 certainly seemed to cause a severe deflection 13.5 seems manageable.  Raising the saddle cures the buzz problem,  I'm concerned that I might create a worse one

[Jeff Highland]

A truss rod should nor be used for other than adjusting relief 10-15 is where I like it for a classical

This affects the action measurements at the 12th so should always be done first.

The nut slots high or low also affect the 12th fret measurement so need to be set before that measurement is taken. If say your nut slot is 1mm too high (not uncommon as it comes from the factory) that will make your 12th fret reading appear 0.5mm higher. So get your nut slots cut to optimum before you measure the 12th fret action.

Target height at the saddle is an important concept when you are building, but unless you are going to change the neck angle, it is out of your control when doing a setup.

I suspect that you may just need a bit higher curvature in your saddle. Measuring the D string height will give you some guidance on this but ONLY after setting relief and nut slots first

[Ned Knepp]

Peter, Jeff knows his stuff so I'm just chipping in to ensure that you realize that he's giving you measurements a the 12th fret NOT the bridge.  

[Paul Verticchio]

A very elementary question: are his strings worn? Any wear spots on the bottom of the strings over those frets will cause buzzing fairly quickly on a nylon stringer.

Also, if he;s the only one that can draw it out of his guitar, you may have a potential customer from hell (totally unable to please him.) It happens.

And to affirm Ned's statement, when it comes to nylon string guitars, Jeff is our "go to" guy. An extremely talented luthier.

Let us know how it turns out?