Question about eliminating wolf tones.

[gaucho]

I have a 1920 Supertone parlor guitar that I love, but I have a problem with it. When playing slide on it I get all kinds of overtones (I believe I've heard these referred to as 'wolf tones"). My technique is certainly not perfect, but I can play slide on all my other guitars (acoustics, electrics and resos) without getting these overtones. I've tried different slides and picks, strings, nuts and I've played with the nut slots, but it doesn't seem to have any effect. Any suggestions?

Here's a photo of the guitar. Not that it helps with anything other than to show that it is worth saving!

[slide496]

Updated for accuracy(hopefully)- usually it happens on stringed violin, chello type instruments. but I read that remedies and devices for those are not applicable to guitars. Some people were able to correct theirs with a higher tension string or changing the brand, tuning differently and some there was something with the guitar that needed attention. Different on each guitar, it seems.

Best of Luck - its a beautiful guitar.

Peace,
Harriet

[Tymus]

Hi Gaucho,

A while ago another forum member "richc" was experiencing similar problems and seeking advise, I've re-posted here my answer........

The problem you are experiencing is almost certainly as suggested a “wolf tone”. Although wolf tones are most commonly associated with Cellos they can occur on any acoustic stringed instrument and are more often to be heard on higher quality better made instruments (than the cheaper ones) due to the fact that they are far more acoustically efficient! Now without going too deep into the physics of acoustics I’ll attempt a “simple“explanation. Everything has its own natural resonance frequency, that is the speed at which it vibrates (measured in Hz), to demonstrate this loosely hold a piece of wood or metal etc. and tap it with your knuckles and you will hear a pitched note. The different parts of the guitar (i.e. soundboard, back, sides and neck) have their own particular resonant frequencies, of which the soundboard is the most important and dominant and is usually pitched two or three tones higher than the back. You may have heard of luthiers “tap tuning” or “voicing”, this is the adjustment of the resonant frequencies by means of altering the mass and or stiffness of the top and back of the instrument. There is another important resonance in the guitar, this is the air resonance inside the body, its frequency is a result of the volume of air in conjunction with the area (and shape) of the soundhole(s), it is known as the Helmholtz resonance. The Helmholtz resonance and the resonances of the soundboard the back and sides etc. act together to form what is known as the “body resonance”. The body resonance can easily be found or heard, hold the guitar in front of you and hum into the soundhole varying the pitch, you will notice at a certain frequency the guitar will start vibrating strongly and start to reinforce the hummed note. The pitch of this is the body resonance’s frequency and it’s usually pitched somewhere around G to A but can be higher or lower, bigger bodies tend to be lower than smaller bodies.

Ok back to the wolf note, a wolf note occurs when the pitch of a note played on the instrument coincides with that of the body resonance resulting in a louder sometimes harsh tone, ironically this is not really a “fault” with the instrument but rather the instrument is actually working at its best!

On your Breedlove I would guess that the body resonance will be G which is the same as the note on your top string fifth fret when tuned to open D. if you play each fret chromatically up the string (without the slide) and listen carefully you should hear that around the “G” that the note becomes slightly clearer and louder, you should also notice the same happening if you play the same note an octave higher or lower but probably to a lesser degree. You may also have noticed that when you played a G chord (in standard tuning) that it was pleasant sounding and somewhat “sweeter” than any other chords played on the guitar!

So what can be done to cure this wolf? Michael suggested trying a heavier gauge string, this would however have the reverse effect making the wolf stronger due to the fact that a higher tension will put more energy into the system, on Cellos sometimes a lighter string is fitted but it often only has a minimum effect. A more efficient result can be obtained by adding a weight to the string between the bridge and tailpiece to dampen the vibrations, you may have noticed this on some violin family instruments. Some Cellists will gently squeeze the instrument between their knees when they play the wolf note to dampen the body’s vibration or will play that particular note with less energy (as do some classical guitarists).

On a guitar you can add some mass to a specific place on the soundboard to dampen certain modes of its vibration and effectively kill off the wolf note. What you need to do is, whilst playing the wolf note, apply firm pressure to the soundboard with the ball of your thumb, you may need a third hand to help you. Keep playing the note whilst slowly moving your thumb all over the soundboard until you find a position where you notice the note to decrease in volume. Next get a piece of “blue-tack” and a small heavy object (a large nut or maybe a pound coin) and stick it to the soundboard at the location where you had your thumb. N.B. Blue-tack should not damage the finish but don’t leave it on there for days! Play the note again and listen to the effect, and adjust the location slightly until you find the position that has most effect, now remove the nut and attach a lighter weight and listen again. Keep doing this until you find the optimum amount of weight needed to bring the wolf note into a balance with the other notes on the instrument. I should point out that any mass added to the soundboard will also have some effect on the whole instrument so it is important to only use the minimum weight necessary. Now make a note of the exact position before removing the blue-tack and weight (coin, nut, washer etc), weigh this and then get a piece of hard/heavy wood and cut it down till it weighs the same, I have used ebony for this. Now the tricky part is to fix this block to the inside of the soundboard at the exact same location as you found earlier! You will need to loosen the strings to gain access through the sound-hole. I used animal glue for this as it’s easily reversible with warm water but a good quality double sided tape should also work well and has the benefit of being easy to remove and reposition if you get the location wrong.

Gaucho, I hope that answer wasn’t too long winded and was of some help or interest to you
Let me know how you get on if you try this, good luck.

Tymus.

[Deleted]

If the wolf note occurs as a result of resonant frequency being matched, would slightly up/downtuning help?
TT

[oldnick]

Deuce,
On the assumption that every frettable note will be played at sometime I think that tuning down half a semitone is the only detuning option. Would this be sufficient? I dont know.

Nick

[gaucho]

I've been tinkering with this for a couple days now. What I seem to be finding is that straight Open G (Spanish, key of G is it?) seems to play pretty well. If I tune down to key of E (my preferred tuning for my other acoustics and resos) I get all kinds of funky wolf tones. Tuning up to the key of F helps a good bit but there is still a hint of wolf tone. I've got John Pearce 13-56 PB on it now and they seem a bit bright. I'm thinking of dropping down to 12s and maybe trying some nickels. I really like the tone I get way down in the key of E, but it seems like this guitar just doesn't like being tuned that low.

[pete1951]

Another possible fix maybe to add wieght to the neck. A capo on the headstock might do something to change the resonance, but tymus has given the best advice .
I have seen brass bridge pins for sale, these have a lot more weight than plasic/wood and also may help, you may not have to use all 6.
PT

[sirjohnalotof]

They're not wolf tones...the guitar is screaming in anguish! What a fantastic instrument to play ragtime, delta pickin', in fact anything other than slide. If you have plenty of other guitars for slide, give this one a break and play something sweet on it ;-)

[Michael Messer]

Hi Gaucho,

It is always difficult to comment on this type of thing without having the guitar in my hands, but I tend to think that if you are tuning in Spanish down to the key of E (BEBEG#B) that it is just too low for the guitar to handle, unless you put very heavy strings on it. Spanish down to F is about as low as it can take.

I do tune that low, but not on six string guitars, only 12 string guitars.

Shine On
Michael

[Deleted]

I wish I could get Wolf tones. They sound great. I sometimes get an echo effect an octave higher than the one I'm playing when I use my reso amplified. Not always, though. I wish I knew houw to encourage it!