Wolf note or dead note

[woodenuff]

My Collings 000-2h has a wolf note on the open G string and also D string- fifth fret (also G). Iv'e searched and read many articles about how to deal with it. I've been putting a dot of poster putty on the top after moving my fingers around to touch and isolate the spot where the sound improves while playing the string. Then moved the putty to the underside of the top in the same place. It helps some but doesn't stop the notes from sounding dead. Now my Collings OM-3 is doing it. I helped it with some bone pins to replace the ebony. This just started on the OM-3.

The 000-2h is a recent acquisition and just received a full setup including new bone nut and saddle. The OM-3 has been with me a while. Humidity levels in the house range from 45-49 per cent. Guitars live in their cases with humidipaks in the proper locations. Suggestions appreciated.
Happy Memorial Day
Harmon

[Pnewsom]

Wolfe notes(quiet or loud) are a resonance/phase issue.

Once you notice the issue its hard to overlook it, but in reality all guitars(electric or acoustic), fiddles, etc have them to some degree. Wolfes in Om's and 000's seem to hang around the G, but if you listen carefully you can see the effect begin at F and disappear at A. Dead notes on dreads seem to hang around E.

The more resonant the instrument the more noticeable the wolf note. Changes in humidity levels can help or exacerbate the condition, and sometimes different weights of strings can make a difference.

While one might hope that amplification would overcome the issue, it doesn't and often makes it more noticeable.

[Alan Carruth]

As with any problem, to solve it you have to understand it. The issue with your Collings 000-2h is coming in at around the usual pitch for the 'main top' resonant mode. You can check this by blocking the sound hole to get rid of the low-pitched 'air' resonance that would mask it, and tapping on the center of the bridge with a finger tip. If it's clear enough you may be able to pick it up with a tuner, or you could use a spectrum analyzer, such as the one in the Android app 'Luthier Lab'.

If that's really the issue then adding some mass at the bridge could help, in two ways: by slowing down the transfer of energy from the string to the top, and by dropping the pitch of the resonance. Ideally you'd add just enough mass at the bridge to drop the pitch to be halfway between F# and G, say around 190 Hz.

It's also possible that there are other things going on. Guitars are complicated (deliberately), so there are lot of places where a 'wolf' can hide. As Pnewsom says, the better the guitar the more likely it is that it has some sort of 'wolf' behavior someplace. IMO, it's only a 'wolf' if it's a problem; otherwise it's a 'feature'.

[woodenuff]

I have read about using poster putty to add mass. I'm trying that now- five pea sized dots stuck to the bridge. Have tried several locations: behind and between the bridge pins, on the wings, etc. No change. Maybe I need more mass?

[Boozehound]

To add on to what Alan said (which I agree 100% with): I think it's unlikely that your 003 that you have had for a while just 'started' doing this. I think it's far more likely that you just started noticing it, and now can't 'not notice' it.

I can empathize as I am tormented by this issue more than most, and it definitely is more present on lightly built guitars. Most people either don't seem to hear it, or aren't bothered by it, but I have a hard time getting past it.

I'll be interested to hear if you find a solution. I've been able to mitigate slightly through string choice and bridge pins, but it never really goes away.

[Alan Carruth]

All guitars (all instruments, really) have resonances that 'color' the sound. A wolf note /dead note happens when a resonance (or more than one) occurs at a played pitch and causes problems. Usually it's the lowest pitched resonances that cause the most trouble. They're more active and cover more area and wider frequency ranges, so they're more likely to couple strongly and cause problems. There are two things you can do: shift the pitch of the resonance that is causing the problem, or make it harder for the string to drive it. Often you do some of both; adding mass on the bridge drops the pitch of the 'main top' resonant mode, and also makes it harder for the strings to move it. Either way you change the sound.

The point is that you have to start by finding the problem. Sometimes that's hard to do. I've had a couple of cases in the past few years where we were simply unable to eliminate a pesky 'wolf'. Both of them were subtle; notes that stood out in a small way, but were different enough to be a problem for some people.

Keep in mind, too, that resonant pitches can change, particularly with changes in humidity. I took a guitar to a luthier convention to use as a demonstration of 'wolf' notes, but the drier air shifted the top resonance enough to eliminate it. Intermittent problems are always the most frustrating ones to solve.

[nikpearson]

Always interesting to read your posts Alan.

I’ve recently been doing some simple experiments into changing the main air resonance of a recently finished classical guitar by altering the sound-hole area with assorted wooden inserts.

What surprised me was that this frequency (without any insert) changed from 101Hz to 97Hz over a period of 4 weeks which I’m assuming is probably down at least in part to the recent hot and humid weather in the U.K.

The Gore/Gilet book has some target frequencies for main body air and top resonances. I measured these on a range of instruments and found that two of the ‘best’ sounding guitars - a Lowden O25 and Bourgeois 00 - deviated furthest from these suggested frequencies.

I’m happy to provide the OP a custom made wooden sound-hole insert to shift the air resonance down. Not going to do much for the aesthetics though ;-)

With pin bridges on a steel-string guitar I’m thinking that changing the material (mass) of the bridge pins would allow a shift in the main top resonance without resorting to putty on a permanent basis. Do you know how much of a mass change is needed to shift this frequency?

[woodenuff]

I installed bone bridge pins in both guitars . There was not much difference in the Collings OM3. It's still most noticeable with fingers. However, Switching picks from a 1.5 Primetone or Wegen to a thinner Clayton Ultem or a Dunlop Ultex helps a lot.

Bone pins in the OOO-2H made a big difference. Not perfect but better.

Gonna just play them and wait for the condition to go away by itself!

[BrunoBlack]

It’s difficult to unhear that. Perhaps it might change a bit when striking at different locations over the sound hole. Try closer to the bridge. Or maybe changing the string choice to see if all strings are alike.

[phil0021]

Thank you for your discussion on wolf/dead notes. It lets me know that I’m neither alone, crazy, or inordinately OCD. My dead note is low E 3rd fret, which means my plain ‘ol G chord doesn’t ring out that boomy bottom end as I would like. This is happening on my new Martin SC13e. Here I am thinking “New design body size for Martin - design flaw!?!” (I can hardly believe myself thinking that.) Part if my issue is my inability to NOT compare the SC13e to my D-28 and my 48 year old 00-21. Hardly fair. It seems to not be as prevalent as when I first noticed it (or am I just accepting the anomaly more and more?) I will continue to experiment with different strings - part of the fun with a new guitar. I may try some different bridge pins to replace my plastic ones. What material would give me the most additional mass? And don’t even suggest $150 liquid metal! Thanks for this discussion!!

[KevinH]

A dead note is the G on the low E string is usually associated with the main air resonance of the guitar body. It's related to the volume of the guitar and the size of the sound hole. So changing bridge pins or adding mass won't likely help. In previous threads Alan Carruth has suggested using cardboard or other material to reduce the size of the sound hole to see if that helps. Basically just take a piece of cardboard, cut out a circle that is somewhat smaller than the sound hole and tape it over the sound hole. Try different sizes. If you find a size that minimizes the dead note, you might consider having a nice wooden insert made.

Originally Posted by phil0021

...My dead note is low E 3rd fret, which means my plain ‘ol G chord doesn’t ring out that boomy bottom end as I would like. This is happening on my new Martin SC13e. ... I will continue to experiment with different strings - part of the fun with a new guitar. I may try some different bridge pins to replace my plastic ones...

[varve]

Originally Posted by KevinH

A dead note is the G on the low E string is usually associated with the main air resonance of the guitar body. It's related to the volume of the guitar and the size of the sound hole. So changing bridge pins or adding mass won't likely help. In previous threads Alan Carruth has suggested using cardboard or other material to reduce the size of the sound hole to see if that helps. Basically just take a piece of cardboard, cut out a circle that is somewhat smaller than the sound hole and tape it over the sound hole. Try different sizes. If you find a size that minimizes the dead note, you might consider having a nice wooden insert made.

That's exactly what I did, Kevin, on a friend's 1970's vintage D18 recently, where the main body resonance fell exactly on G2 (98 Hz), and the second frequency (T1,1)2 fell on G3 , one octave above. This was a very unfortunate situation, the guitar had always been a bit of a dud - but this soundhole insert dropped the body resonance 4 Hz, to 94, and what a difference it made to the fretted G (sustain doubled), and the entire G chord blossomed. I later added mass to the sides, with a strip of copper (950 grams), attached to the sides at the level of the kerfing with brass screws. This dropped the second frequency by 5-6 Hz, and increased the loudness audibly. This dud of an old D18 suddenly sounded like a good to above average D18 - really good, in other words . Take out the soundhole insert, however, and the guitar is back to being a dud. I'm convinced by the Gore/Gilet theory and practice
Dave Olson

[Banditos]

Hi, may I ask what happened with that guitar? I have the exact same issue with an HD 28 the low E string 3rd fret G note is dead or wolf, loud first then no decay/sustain. I am curious how to resolve this. Bought it second hand, so return is not an option. Was thinking of (after reading some forums) to replace some pins to brass. I know it is a bit older thread, but hopefully I can revive it!

Originally Posted by phil0021

Thank you for your discussion on wolf/dead notes. It lets me know that I’m neither alone, crazy, or inordinately OCD. My dead note is low E 3rd fret, which means my plain ‘ol G chord doesn’t ring out that boomy bottom end as I would like. This is happening on my new Martin SC13e. Here I am thinking “New design body size for Martin - design flaw!?!” (I can hardly believe myself thinking that.) Part if my issue is my inability to NOT compare the SC13e to my D-28 and my 48 year old 00-21. Hardly fair. It seems to not be as prevalent as when I first noticed it (or am I just accepting the anomaly more and more?) I will continue to experiment with different strings - part of the fun with a new guitar. I may try some different bridge pins to replace my plastic ones. What material would give me the most additional mass? And don’t even suggest $150 liquid metal! Thanks for this discussion!!

[Alan Carruth]

As Kevin H said, the thuddy low G is usually an issue with the 'main air' resonance. This is actually a more complex thing than it might seem. It's a 'Helmholtz-type' resonance, which usually means that it's pitch is mostly determined by box volume and the size and location of the hole. However, on the guitar the vibration of the top and back also enter into the mix, which is why the folks who try to predict the 'air' resonance on a guitar using Helmholtz' equation get it wrong. It turns out that often the best way to fix this problem is by shaving back braces, particularly the two lower ones. One would, of course, check out what the actual issue is before making such permanent changes. In this case you can add weight to the back to lower it's resonant pitch, which is what shaving braces will do, to see if it might work. If it doesn't there's no harm done, and you learned something.