Wolf tones

**dorenac** · Dec-18-2008, 10:05am

Trying to eliminate/control wolf tones on the D strings on my old Gibson. Have been consulting with two regular contributors/luthiers on this site already and the diagnosis has progressed fairly well. At least one location on the top plate has been isolated. But everything stalls when trying to determine a good course of action to pursue from that point. I might add that the top has been shaved and so is probably too thin to shave any further. I would appreciate any ideas others have successfully tried.

**MikeEdgerton** · Dec-18-2008, 11:18am

Actually you probably have harmonic overtones. Roll up a one dollar bill and weave it through the strings behind the bridge and in front of the tailpiece. Do they stop?

**dorenac** · Dec-18-2008, 11:34am

No, they don't. They occur on the D strings at the 4th and 6th frets. If I place 6gm. of clay, wood, whatever on a particular spot on the top plate, it seems to disappear for the most part. But I also lose some color tones at those notes also. The sound in somewhat harsh and lifeless.

**MikeEdgerton** · Dec-18-2008, 11:58am

What does it sound like? The classic wolftones aren't supposed to exist on fretted instrument.

**dorenac** · Dec-18-2008, 12:13pm

They are rare on plucked instruments. It is a flat, hollow, somewhat harsh sound. It is on pitch, though. I've taken it to a builder and talked to another. For a lack of any other description we a calling them wolf tones.
There is an ever so slight sound like that on the open A strings also, but not when they are fretted. I will add that the top is slightly sunken, too. The bridge has a solid foot, although it's a cheapy and adjustable, not original. But it is properly set up, and fits the top well.

**Jake Wildwood** · Dec-18-2008, 3:22pm

Is it possible you have loose bracing, kerfling, etc?

From my experience some frequencies will vibrate imperceptibly loose structural elements in ugly ways (that don't sound quite like a loose piece). I see these "wolf tones" (they sound like them) a lot on old, very lightly built ukes.

**dorenac** · Dec-18-2008, 5:11pm

Again, as I said earlier, one luthier has seen & inspected it. A repair guy has looked at it. It was set up by a third outfit in Nashville. That's not to say something wasn't overlooked, but I don't suspect anything loose. Back to my original question though. What about solutions?

**Dave Cohen** · Dec-18-2008, 9:20pm

Rich, I couldn't find anything specific in any of my lutherie archives, but I remembered that I saw something related. Australian guitar luthier Greg Smallman, in developing his balsa/CF lattice braced classical guitar tops, was going for extreme lightness in his plates. That also made the modal frequencies higher, though. He was able to "bring some of them back" by adding masses to the insides of the top plates. There was an article on him in American Lutherie way back, but at the moment, I can't find it. Anyway, Smallman did add mass in the form of a blob of epoxy, iirc. Not epoxy layers, but a blob. That was fine for his radically redsigned new guitars, where much CF and epoxy was already present. I'm not so sure, though, about a vintage instrument. At the moment, I am favoring gluing a preweighed mass of a dense wood on the inside of the top plate with hot hide glue. As I had said to you, that gives the advantage of both reversibility and fast tack.

http://www.Cohenmando.com

**Michael Lewis** · Dec-19-2008, 3:18am

You mentioned the top is thin. How thin, and where?

Also, you mentioned the top is sinking a bit, you may not have to worry about it much longer.

**dorenac** · Dec-19-2008, 6:07am

Thanks Dave, I've been playing around with applying putty as you know. But last night I tried a small piece, again 6gm is the magic number, of vera vera wood. With its "omni-directional" grain pattern that really deadened the tone, but all the color tones as well. So in thinking what made the putty more desireable I added a thin, cork sheet, say 1mm+/- under the vera vera and taped the whole thing to the top. I liked the results. Similar to putty. Later today I will go back and listen some more. But thanks for the tip about Smallman, too, as well as the epoxy. My intuition is telling me "dense yet not dead". This may end up being a laminate say macassar and vera vera, or cork or something. Will keep at this for a while.