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I play the guitars I make and sometimes I am annoyed at cancellation of certain notes or lack of sustain I am calling Wolf tones. If you “sing” a sweep of notes into your guitar’s sound hole, you will notice certain notes will make the guitar body vibrate. If I play the most active note on the strings, it can sound dead or it will sustain less than the other notes. I am starting to understand why this happens but would like to know what, if anything do you do during construction to lessen the effects of Wolf tones?
Almost all my acoustic guitars have numb notes at middle “A flat” give or take.
Should I “tune” the soundboard away from this note?
If so, how is that done and when do you do it, before or after bracing?
Thanks,
Wade

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Wade
Nashua, NH
http://www.wadefx.com

Wade

I've found that wolf notes can be controlled more by variation in the back bracing. Triangular cross section with scalloped ends seems to work for me. Although I tend to use parabolic back struts (ladder or X) now as I like the more explosive kick they give for my desired Celtic sound, on my OMs anyway. I use a parabolic X strut on the sound board as well for the same reason. (sometimes with parabolic tone bars as well).

More experienced minds than mine will probably give you a more reasoned argument though.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Just Switch to Adirondack Spruce Braces and..... all your troubles will go away. I'm familiar with wolf tones in violin family instruments. And from what I understand it's exactly opposite to what you describe.

Your description sounds like notes fall into a black hole, deadening those notes. From my understanding, wolf notes are sympathetic vibrations in an instrument at the same pitch of the vibrating fretted note. In other words, an amplification or actually louder sound rather than a deadening of sound.

Cellos for instance have wolf tone inhibitors placed at locations on the cello to dampen that wolf note. I see a parallel too, to the sound of a growling wolf. That's what the note does it kind of snarls out during playing, much out of place and noticeable.

But on guitar, you hardly ever hear about this. I'd say it might be more prevalent on an archtop rather than a flattop or dometop acoustic. Okay, gotta go saw some wood. Good luck someone with acoustic prowess may be along any moment. Enjoyed the chit chat.

Wade, I can't be much help. However, Al Carruth is the guy who can help you. This has been discussed over at the Acoustic Guitar Magazine Luthiers Forum so you might do a search on their site. Hope this helps a little.Don A38365.6548958333

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Don Atwood
Arlington, VA

Thanks muchly guys!
I know it is a subtle thing but it still bugs me.
Colin, I would not have thought the back bracing could be the culprit. Or top brace material either.
Great, this gives me something to try on the next build.
Thanks Don, I'll check that forum.

Wade

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Wade
Nashua, NH
http://www.wadefx.com

Dicky,
Are you serious about Adirondack spruce braces? If so, do you know a sorce for the stuff? I’ve been splitting my own lately.
As far as wolf notes,
Alan Carruth wrote in response to this subject that hits it on the head.
Quote,
“It sounds to me like you're hearing the usual guitar 'wolf note'. If you tap on the top you will probably hear that F# or G as the resonance. Most of what you perceive is the 'main air' resonance, but the 'main top' mode is often pretty nearly an octave higher. In that case the two will conspire to 'suck' all of the energy out of the fundamental and first harmonic of the string and feed it out into the air. The note tends to be twice as loud for half as long as the ones on either side of it. You're not as aware of the extra volume as you are of the lost sustain, so it's a problem.
The only real solution is to change one of the resonances. An easy way is to block off part of the soundhole, which will lower the air resonance. You can drop the pitch of the top resonance by adding weight at the bridge or shaving braces (carefully!). Just don't lower both the air and the wood tones at the same time, or you could end up with the same problem only on F.”
I hope this is ok to post a quote.

So through further investigation of this topic, I can understand why others are hesitating to “chime in” with their thoughts and feelings. This seems to be one of the mysteries of the craft. Although Alan Carruth (and I’m sure many others) seems to have a handle on unraveling some of how and why the guitar dose what it does. Also, his willingness to share his findings I find inspiring not to mention helpful for all of us trying to improve our guitar building ability. Still, there is so much about the guitar that remains mysterious. There is much room for improvement. I would imagine it would take one person many builds before getting a good sense of what goes on with the sound of the guitar and what he or she changes during assembly that makes that sound better. Just maybe Forums like this give us the opportunity to share what works so we all contribute to the refinement of the Craft. I’d like to thank you all ahead of time because I believe we will make it so.
OK I’ll shut up now..

Wade

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Wade
Nashua, NH
http://www.wadefx.com

Wade, I've not had a problem with wolf notes, just know they exist. Alan's description is pretty perceptive and very astute. I think it's okay to share quotes, as long as you have permission from the man... grin.

I was kidding about the braces being the answer, but there was a bit of truth in them being important to a great sounding guitar.

Try this link: tell John, Bruce in Arkansas sent ya.

Addy Ron Dak frum Jon Grifn......

I just unboxed a load of tops and bracestock last e'n!

I'd have hopped in with an answer myself a day or two ago, but had to re-register. I've had the 'duty cold' that everybody up hereabouts has got, and was not running on all (both) cylenders, so I just let it ride.

The interesting thing is that the 'wolf' in the 'cello and the guitar can actually have much the same cause, even though the effect is so much different. The reason is that with a bow you can keep feeding in energy to replace what's 'lost', from the strings point of view, and that drives the whole system into seriously antisocial behaviors. I've heard 'cellos that just bleat like a sheep on that one note, as noble as they sound everywhere else.

In point of fact, there tend to be 'wolfy' frequencies on all guitars: and more on the better ones. The difference seems to be, in some part, that good instruments tend to have enough other stuff going on that you don't notice. Other than that I don't know of any relaible and universal cure for the wolf.