The Acoustic Guitar Forum

Go Back   The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Build and Repair

Reply
 
Thread Tools
  #1  
Old 11-17-2011, 03:08 AM
IndianaGeo IndianaGeo is offline
Registered User
 
Join Date: Nov 2008
Posts: 1,471
Default "Thumpy" or "non-sustaining" frets

Hi All,
I played a guitar the other day that was by all accounts a great looking acoustic guitar. But I sensed a few fretted notes on two (E and A) strings lacked the sustain that most all the other fretted notes had. Is this common? What causes it? Is it fixable? It wasn't all that bothersome, but I wondered about it. Is this the "wolf note" phenomena?

Regards,
IG
__________________
2006 Gibson Les Paul Std
2011 Ron Kirn Strat Style
2011 Taylor 714c
2014 Shippey Oval Hole Mandolin
2016 Martin HD28.
Schertler Jam 150 amp.
Neumann TLM 102 mic.
Reply With Quote
  #2  
Old 11-17-2011, 03:54 AM
gitnoob gitnoob is offline
Registered User
 
Join Date: Jun 2009
Location: Emerald City
Posts: 4,327
Default

Sounds like a wolf note to me.

To verify that it is, try dropping the tuning down a semi-tone or two. That should tell you if it's frequency related or fret related.

If it's a wolf, not a whole lot you can do about it. It's the result of some part of the instrument resonating strongly at those frequencies, so all of the energy goes WOLF! at once with no sustain.

If it were me, I might experiment by adding mass at locations I think might be responsible for the resonance -- added mass will lower the resonant frequency.
__________________

gits: good and plenty
chops: snickers
Reply With Quote
  #3  
Old 11-17-2011, 05:11 AM
IndianaGeo IndianaGeo is offline
Registered User
 
Join Date: Nov 2008
Posts: 1,471
Default

Quote:
Originally Posted by gitnoob View Post
Sounds like a wolf note to me.

To verify that it is, try dropping the tuning down a semi-tone or two. That should tell you if it's frequency related or fret related.

If it's a wolf, not a whole lot you can do about it. It's the result of some part of the instrument resonating strongly at those frequencies, so all of the energy goes WOLF! at once with no sustain.

If it were me, I might experiment by adding mass at locations I think might be responsible for the resonance -- added mass will lower the resonant frequency.
Sounds interesting. What "mass" can one add? Would something (say, a small smooth rock or whatever) taped to the top of the guitar be what you're talking about?

IG
__________________
2006 Gibson Les Paul Std
2011 Ron Kirn Strat Style
2011 Taylor 714c
2014 Shippey Oval Hole Mandolin
2016 Martin HD28.
Schertler Jam 150 amp.
Neumann TLM 102 mic.
Reply With Quote
  #4  
Old 11-17-2011, 10:21 AM
charles Tauber charles Tauber is offline
Registered User
 
Join Date: Feb 2011
Posts: 8,381
Default

In some cases, I've found that the "dead" notes are a result of loose frets that vibrate in their slots, dissipating string energy.

Easy test is to press the eraser-end of a pencil against the fret while playing the "dead" notes.
Reply With Quote
  #5  
Old 11-17-2011, 11:58 AM
gitnoob gitnoob is offline
Registered User
 
Join Date: Jun 2009
Location: Emerald City
Posts: 4,327
Default

Quote:
Originally Posted by IndianaGeo View Post
Sounds interesting. What "mass" can one add? Would something (say, a small smooth rock or whatever) taped to the top of the guitar be what you're talking about?
I believe there's actually a traditional material and location: I've found coins glued to the bridge plate in some old guitars.

Taping something like a coin will probably cause unwanted vibration. I'd use something like adhesive putty.

But as Charles mentioned, you first need to rule out fret issues. He mentioned loose frets. It's also possible to get "quiet" back buzz that kills the string's vibrations without buzzing.

Finally, sustain naturally changes with string length and frequency, so some notes just don't sustain as long as others.
__________________

gits: good and plenty
chops: snickers
Reply With Quote
  #6  
Old 11-17-2011, 12:26 PM
Misty44 Misty44 is offline
Registered User
 
Join Date: Feb 2008
Location: Cambridge, Massachusetts
Posts: 3,028
Default

Quote:
Originally Posted by IndianaGeo View Post
Sounds interesting. What "mass" can one add? Would something (say, a small smooth rock or whatever) taped to the top of the guitar be what you're talking about?

IG
Adding mass on/around the plate will sometimes boost the bass response. While this may seem counterproductive, in the right place more mass can be a good thing.

Mass can be added in the form of heavier pins, a cross brace in front of the plate, and "weights" (nuts, coins) taped to the front of the plate between the X braces. One way to experiment is by applying various amounts of poster clay to the plate and/or top/bottom braces (it's non-oily and won't leave a residue).

Sometimes these things work for the better, sometimes not, but they're all easy to remove with no harm to the guitar.

But adding weight is for the tone, I don't think it will help your fret problem.
Reply With Quote
  #7  
Old 11-17-2011, 01:37 PM
Alan Carruth Alan Carruth is offline
Registered User
 
Join Date: Feb 2011
Posts: 4,180
Default

There's not nearly enough information in the original post to say whether it's a 'wolf' problem or something else. I'd check out the 'usual suspects', such as frets, first, and only then go hunting wolves. There are lots of places wolves can lurk, and some of them can be easier to fix than others. Adding mass iv various spots (I like poster adhesive) is a good way to check for a wolf, but it helps a lot to know just what breed of dog you're dealing with.
Reply With Quote
  #8  
Old 11-18-2011, 12:13 PM
IndianaGeo IndianaGeo is offline
Registered User
 
Join Date: Nov 2008
Posts: 1,471
Default

Quote:
Originally Posted by Alan Carruth View Post
There's not nearly enough information in the original post to say whether it's a 'wolf' problem or something else. I'd check out the 'usual suspects', such as frets, first, and only then go hunting wolves. There are lots of places wolves can lurk, and some of them can be easier to fix than others. Adding mass iv various spots (I like poster adhesive) is a good way to check for a wolf, but it helps a lot to know just what breed of dog you're dealing with.
Hi Alan,
I'll try to describe a bit better: When playing the low E string on the "G" (3rd fret) for example, the sound is not very sustaining. It decays very quickly in more a hollow thump than a ringing, vibrating note. It bewilders me a bit because I wonder how a string can apparently not vibrate much despite being struck firmly. It "sounds" like a G note, but just doesn't "ring". It happens to a lesser degree on the G# on that low E string. There are a couple of other spots that exhibit the same thing. If I recall correctly, it also happens on the D string on the F# (4th Fret). I believe it also happens on the D string on the 10th fret (C note). Virtually all other notes surely sustain for longer durations. They "ring" out. It was on a Taylor 814. I've not had a chance to do the pencil eraser test described earlier in the thread (i.e. to check for unseated fret). All the strings ring fine If you need a further description, I'll do my best to answer. Thanks.

IG
__________________
2006 Gibson Les Paul Std
2011 Ron Kirn Strat Style
2011 Taylor 714c
2014 Shippey Oval Hole Mandolin
2016 Martin HD28.
Schertler Jam 150 amp.
Neumann TLM 102 mic.
Reply With Quote
  #9  
Old 11-18-2011, 12:38 PM
bobby b bobby b is offline
Registered User
 
Join Date: Apr 2011
Posts: 992
Default

Tune the strings up 1/2 a step and see if the low G ( now at the 2nd fret or down a step so the low G is now at the 5th fret ) exhibits the same response, if so, it sounds wolfie to me.
__________________
D'ya like my red dot....
Reply With Quote
  #10  
Old 11-18-2011, 12:45 PM
IndianaGeo IndianaGeo is offline
Registered User
 
Join Date: Nov 2008
Posts: 1,471
Default

Quote:
Originally Posted by bobby b View Post
Tune the strings up 1/2 a step and see if the low G ( now at the 2nd fret or down a step so the low G is now at the 5th fret ) exhibits the same response, if so, it sounds wolfie to me.
Hi Bobby, Are wolf tones common? I read somewhere even some well regarded instruments have them. Is it just the resonant nature of the instrument itself that creates this? I'm fairly new to the acoustical world (but not to guitars in general).
Cheers,
IG
__________________
2006 Gibson Les Paul Std
2011 Ron Kirn Strat Style
2011 Taylor 714c
2014 Shippey Oval Hole Mandolin
2016 Martin HD28.
Schertler Jam 150 amp.
Neumann TLM 102 mic.
Reply With Quote
  #11  
Old 11-18-2011, 12:47 PM
badbazil badbazil is offline
Registered User
 
Join Date: Jan 2011
Posts: 454
Default

You should pass on the guitar. There are too many guitars for sale to buy a subpare one that you are going to have to have repaired.
Reply With Quote
  #12  
Old 11-18-2011, 01:31 PM
bobby b bobby b is offline
Registered User
 
Join Date: Apr 2011
Posts: 992
Default

Quote:
Originally Posted by IndianaGeo View Post
Hi Bobby, Are wolf tones common? I read somewhere even some well regarded instruments have them. Is it just the resonant nature of the instrument itself that creates this? I'm fairly new to the acoustical world (but not to guitars in general).
Cheers,
IG
Somewhat common, dont know if I would say very common.... and yes, it has to do with conflicting resonances inherent to the particular guitars' design and materials.
Each instrument, even equal models, being made from organic materials, will vary, each may have wolf tones to a greater or much lesser degree.
__________________
D'ya like my red dot....
Reply With Quote
  #13  
Old 11-18-2011, 01:51 PM
Alan Carruth Alan Carruth is offline
Registered User
 
Join Date: Feb 2011
Posts: 4,180
Default

That sounds like a wolf to me. The low G or G# is often quite close in pitch to the 'main air' resonant frequency, and whan that happens the note can be 'thumpy'. All the energy is being extracted from the string in a hurry, and pumped out as sound, so it's twice as loud for half as long. Your ears aren't very sensitive to the change in volume, but you can sure hear the lack of sustain.

Aside from changing the pitch of the string to see if it's pitch related, you could also try coving part of the soundhole with a stiff card or some such, to alter (lower) the pitch of the 'air' resonace. Sometimes you can hear the 'main air' pitch by singing into the soundhole: just keep your face at least 4"{ away from the top, and further if possible: too close will change the pitch of the resonance.

In general, 'wolf' notes are caused by interactions beween resonances of the guitar and the strings. Good guitars tand to have more and stronger resonances, so they actually can show more evidence of wolf notes than poor ones. It is sometimes possible to position these resonances in between played pitches, so they aren't so much of a problem, but the resonances can shift with changes in humidity and other things, so that might not work in every case. These things are also more complicated than they seem on the surface, which is what makes wolf hunting a risky business.
Reply With Quote
  #14  
Old 11-19-2011, 08:10 AM
IndianaGeo IndianaGeo is offline
Registered User
 
Join Date: Nov 2008
Posts: 1,471
Default

Quote:
Originally Posted by Alan Carruth View Post
It is sometimes possible to position these resonances in between played pitches, so they aren't so much of a problem, but the resonances can shift with changes in humidity and other things, so that might not work in every case. These things are also more complicated than they seem on the surface, which is what makes wolf hunting a risky business.
Thanks Alan and others,
Very informative and interesting. I tried the guitar again and the wolf note seemed to sustain a bit more today. Maybe it was because, as you say, a change in humidity. Thanks again.

IG
__________________
2006 Gibson Les Paul Std
2011 Ron Kirn Strat Style
2011 Taylor 714c
2014 Shippey Oval Hole Mandolin
2016 Martin HD28.
Schertler Jam 150 amp.
Neumann TLM 102 mic.
Reply With Quote
Reply

  The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Build and Repair

Thread Tools





All times are GMT -6. The time now is 12:39 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ©2000 - 2022, The Acoustic Guitar Forum
vB Ad Management by =RedTyger=