Wolf tone tail piece adjustment

stringblunder · #1 09-22-2010, 10:12 PM

Hi everyone, I have a Kolstein Fendt model bass that I have had fitted with a C Extension. This bass suffers (and so do I) from a bad wolf on the open G string. when I open the extension even partially it moves the wolf lower, down to some where between F and F#. I have tried a few types of wolf eliminators in several different locations, as well as tuning the after length to different intervals and was never impressed by how they almost muted my bass completely or made the bass less responsive.
Recently, It was suggested that the position of the tail piece was incorrect and that it could be moved down a 1/2 inch. This is to make the after length on the G string tuned to a B instead of the C that it is currently tuned to. I was wondering whether anyone has done this and found success with this method of killing or relocating wolfs. Thanks

Eric Hochberg · #2 09-22-2010, 10:18 PM

I moved my tp up and down and did not notice a change in the Ab wolftone. A Marvin tailpiece moved the wolf up to an A. Some people have reported the Marvin eliminates wolfs. Not on my bass. You might try a different weight tp, too.

bassrome · #3 09-25-2010, 04:05 PM

You might be able to move it by changing to a lighter (or heavier) tailpiece. Also, removing some wood underneath the fingerboard in the direction where it comes of the neck might help. The idea is to lower the resonant frequency to a less objectionable place and then tweak the soundpost so that it moves into thumb position on the A string.

Cheers,
Jack Hill
JD Hill Music

Jay VandeKopple · #4 09-26-2010, 01:01 AM

You can sometimes gain something by tuning the tailpiece vibration itself to the wolf note (or octave above). That's why lighter tailpieces can help, as well as removing some wood. In effect, you turn the whole tp into a wolf suppressor.

It can be tricky hearing the tailpiece frequency. I've seen some people bow on the tailpiece just below the string attachments. However, it's hard for me to hear, and it can make for a pretty messy tailpiece, coated with rosin.

You can also check the tailpiece frequency quite easily with a "Fuhr tube" (a thin glass capillary tube). With wet fingers, you get the same type of action as with a drinking glass. The slip-grip action of fingers along the glass against the tp generates an audible resonance frequency. You need to hold the tube at the upper end of the tp. (You'd get a different frequency at the lower end of the tp.)

On occasion I've had some success with adjusting the length of the tailwire so the tp frequency (at the upper end) matches the wolf note. It needs more testing, though, before I'd rely on it as a tried & true fix. So far I consider it as one of the options.

arnoldschnitzer · #5 09-26-2010, 07:34 AM

I just wanted to post and express my excitement at having Dr. VandeKopple onboard this forum. A nicer person never picked up a bass bow! And by way of qualifications, Jay is a lifelong bassist and luthier, and is married to one of the world's top bass pedagogues, Linda McKnight. Jay is my secret acoustics guru. He has helped me on several occasions when I had run out of tricks. It helps that he has a decades-long connection with the Catgut Acoustical Society, which is now part of the VSA. Welcome Doctor Jay...

Jake deVilliers · #6 09-26-2010, 12:29 PM

Quote:

Originally Posted by arnoldschnitzer

I just wanted to post and express my excitement at having Dr. VandeKopple onboard this forum. A nicer person never picked up a bass bow! And by way of qualifications, Jay is a lifelong bassist and luthier, and is married to one of the world's top bass pedagogues, Linda McKnight. Jay is my secret acoustics guru. He has helped me on several occasions when I had run out of tricks. It helps that he has a decades-long connection with the Catgut Acoustical Society, which is now part of the VSA. Welcome Doctor Jay...

Very cool!

It seems that Dr Jay should fill in his profile, yes?

Jay VandeKopple · #7 09-28-2010, 12:18 AM

Quote:

Originally Posted by Jake deVilliers

Very cool!

It seems that Dr Jay should fill in his profile, yes?

Wow, Arnold - Thanks for such kind words. You've helped me so much that I'm glad if I can help some in return. (I couldn't find a blushing icon to fit in here.)

stringblunder · #8 10-01-2010, 11:39 PM

thanks for the suggestions, I will keep them in mind as I work with the local luthier over the next few weeks to hopefully come up with a good solution.

Eric Swanson · #9 10-02-2010, 05:55 AM

I eliminated wolf tones from a fairly poor bass by swapping the tailpiece for a Marvin wire tailpiece. The effect of this, if I understand the AO-BO matching concept (at all), was to effectively remove the tailpiece from the vibratory equation.

On the plus side, all wolfs dissappeared, in that case, the bass spoke very evenly from top to bottom, and all notes were equally clear.

On the negative side, I have also heard of, and heard, basses that completely lost their "guts" when a Marvin was installed. Plus, the bass I did it on was so heavily wooded and crudely wrought that it may not count for much.

I have not (yet) tried the Marvin on my current bass (and may not); this bass is so responsive, I am moving very slowly in experimenting with one element at a time. Haven't gotten to the tailpiece yet.

The Marvin is a relatively inexpensive ($80) option for experimentation, just to add it to the range of possibilities. It seems, perhaps, like the ultimate extreme of eliminating tailpiece mass (to nearly zero).

Dr. VandeKopple, do you have any experience with these wire tailpieces, or ideas on when (or, if ever) they may/may not be a helpful, possible option (when might they be something to add to the list of "things to try")?

bejoyous · #10 10-02-2010, 09:11 AM

I agree about the wire tailpiece. Another excellent light weight TP is the Wittner composite one. If you get this, don't use the nylon tailgut that comes with it as it creates a bit f
of friction as it goes over the saddle and can pull it off the bass when up to tension.

The ideal placement of the TP is such that the after length of the string is 1/6th the string length. That way the bridge sits in a harmonic node and the tuning of the after length doesn't create an interfering overtone that causes the wolftone. (or so the theory goes.)

stringblunder · #11 10-04-2010, 10:00 PM

I have heard that the wire tailpieces also have the potential to create extra wolf tones?

bejoyous · #12 10-04-2010, 11:18 PM

Well on my homemade wire tailpiece, when there was no damping, they would ring in sympathy the same note as the open G-string. I solved this by weaving a flat shoelace around the wires near the bottom. I believe the Marvin one has a piece of felt that is glued on and trimmed to shape.

As for wolf notes from the bass, they are all gone. I found my bass literally sounds like its pricetag should be $10 000 higher.

Jay VandeKopple · #13 10-05-2010, 11:44 PM

Quote:

Originally Posted by Eric Swanson

I eliminated wolf tones from a fairly poor bass by swapping the tailpiece for a Marvin wire tailpiece. The effect of this, if I understand the AO-BO matching concept (at all), was to effectively remove the tailpiece from the vibratory equation.

On the plus side, all wolfs dissappeared, in that case, the bass spoke very evenly from top to bottom, and all notes were equally clear.

On the negative side, I have also heard of, and heard, basses that completely lost their "guts" when a Marvin was installed. Plus, the bass I did it on was so heavily wooded and crudely wrought that it may not count for much.

I have not (yet) tried the Marvin on my current bass (and may not); this bass is so responsive, I am moving very slowly in experimenting with one element at a time. Haven't gotten to the tailpiece yet.

The Marvin is a relatively inexpensive ($80) option for experimentation, just to add it to the range of possibilities. It seems, perhaps, like the ultimate extreme of eliminating tailpiece mass (to nearly zero).

Dr. VandeKopple, do you have any experience with these wire tailpieces, or ideas on when (or, if ever) they may/may not be a helpful, possible option (when might they be something to add to the list of "things to try")?

It's still on the list at this point. I haven't had a chance to do some testing on it, but it seems to depend on the bass, from those who have tried it.

We had hoped to try some testing at the VSA/Oberlin Bass Workshop last summer. David Gage had gotten one sent out, but it was getting too late in the week to try it. People pretty much were already buried in the projects they were working on.

For a wolf I'll usually start out with checking the post and the tailpiece frequencies (and may adjust tailwire length). Looking at all the options can take quite a bit of time, and some customers find it most practical (and cost-effective) to take the first option that improves things. Sometimes a wolf suppressor (that goes on the afterlength) actually does help a bit - enough to help them play thumb position on the A string without fighting the wolf much.