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Jim25

Help with strange (wolf?) note

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I'm hoping someone will be able to help me with a problem I seem to have with my violin.

I've looked at several examples of wolf tones on YouTube, just to check if that's what I'm experiencing and I'm really not sure.

I seem to have a problem with my open A string (I've heard that A isn't usually a wolf note?)

When playing the open A, the string almost seems to stiffen and resist the bow. The note is overly strong & resonant, but decays almost immediately if you lift the bow. There seems to be a strong harmonic overtone you can hear.

Because it's on an open string, I've been able to prod and press all around the violin whilst playing the note without any solution.

I have found one remedy and that was if I press down on the A in first position on the D string. Then play the open A, it's perfect. The note thins out, loses the strange heavy overtone, and sustains perfectly if you lift the bow. If I slide my finger up or down on the D string from the A note whilst bowing the open A string, you can hear the heavy overtone creep back in & the string tense etc etc.

If anyone can offer any advice or further explanation I would greatly appreciate it. Aside from this glaring note, it's an otherwise beautifully warm and resonant sounding instrument.

I tried looking on the G string for the typical wolf tones I've heard before in high positions, where you have that fluttering stop/start sound. I managed to find one but it was a little difficult to bring out. It sits on the quarter tone between G# and Ab.

Thank you for any help! So frustrated!

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Hi Jim.

 

The A note at 440 Hz may be very close to the B1- basic resonance of your violin. What comes to my mind is first a test:

 

1)  Tune the violin to a very low A say 435 Hz. Did the problem go away? Then tune it high to say 444 Hz and test it.

 

If some of the alternative tunings helped or lessened the problem you can try:

 

2) Remove your chin rest and play temporarily without it. Did the problem go away?

 

If some of the tests above helped you can try to go forward. Adding a chin rest changes the B1- resonance quite a lot. Now without seeing/hearing the actual instrument it is not possible to say anything for sure. I would check the chin rest top cork strip, very often it is absurdly wide. Make the strip narrower and probably B1- will rise and you may get rid of your problem. Alternatively if you are using a wooden chin rest try for example a composite Wittner chin rest (roughly half the mass of a traditional one). You can also try a symmetric chin rest sitting symmetrically over the tai piece.

 

These alternatives are easy to try out and you can always go back to the old situation ... ok if you used a knife to narrow the cork strip you have to glue a new one in place.

 

Getting rid of a problem with a violin resonance is often a question of moving it somewhere where it doesn't get into your way.

 

If this helps pleas let us know!

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Thank you Lars

It has a Guarneri style rosewood chinrest at the moment, so the cork feet are either side of the tailpiece. I tried a heavier teka style rest which clamps over the side and also tried with no chin rest. Sadly this has no effect.

I tried tuning down about a quarter tone, and that seems to begin to diminish the heavy resonance feeling, although the ringing overtone is still apparent. But heading in the right direction.

I had the soundpost shifted and a new wittner tailpiece put on about 2 months ago and I'm almost certain that's when it began, although I could be mistaken. I've been trying my hardest to remember if it's something I've noticed before or not.

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I'm hoping someone will be able to help me with a problem I seem to have with my violin.

I've looked at several examples of wolf tones on YouTube, just to check if that's what I'm experiencing and I'm really not sure.

 Thank you for any help! So frustrated!

 

Yes, detune your violin and see if it is the note -  or perhaps it is the nut and the string groove through the nut?

If detuning doesn't change the open A wolf,

I'd perhaps check the "a" string groove at the nut for a; "too close to the fb problem"...

 

If neither of these things works, let us know - there are plenty of other things to try.

 

Please keep us informed about how and if you resolve this problem.

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As Lars said, one of the two strongest body modes is likely at or very close to A.  There is also another structural vibration mode about an octave above that.

If you could post a recording of a semitone scale around A (say G thru B; just 5 notes) without vibrato, that might help figure it out.  Since you're a new member, you might not be able to do that yet; you can email to me directly (dnoon1200@aol.com).

 

If you do get around to recording, also record those notes an octave down, on the low G string.

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Can I just say thank you to everyone that has replied, I've emailed Don a couple of audio samples.

My replies have to be moderated which is why I'm so slow responding.

If it helps any, it's a late 1800's German violin. Unlabeled, but nicely made.

I've been wracking my brains trying to remember how it was before I had the sound post shifted and the new tailpiece put on. I've not owned it very long you see. I think possibly afterwards I did notice the A string sounded very strident, but put this down to soundpost adjustment that I'd have to get used to. The post initially was in an odd place, slightly further back and towards the bass side.

It was only more recently when I played it more, that I started to really notice it & figure that it was actually a bit of a problem that the note was sticking out so much. I was having to work at disguising the note. That was when a google search lead me onto reading about wolf notes and subsequently this forum!

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Here is the plot of the scale sent to me by Jim25.  It's not a semitone scale, but one octave of a D scale including the open A:

 

post-25192-0-25965200-1402101272_thumb.jpg

 

As expected, the A440 is far stronger than the adjacent notes... to the tune of 13.5 and 16 dB stronger.  That's a huge difference.  The first harmonic at 880 does not appear to be an issue.  Using the stopped D string (at A) knocks the 440 resonance down significantly, and is a great demonstration of a "non-radiating resonator"... where the input from the bowed string goes into the sympathetic resonator instead of the body of the violin.

 

This is definitely a strong B1- body resonance, primarily a back vibration.  If you feel what's vibrating when playing the open A, it should be the back, slightly to the bass side, that's vibrating the strongest.  The fact that high G string notes are less vulnerable is another clue that it's not a B1+ resonance (and I've never seen a B1+ frequency that low).

 

I think the most important adjustment would be the lateral position of the soundpost.  The farther out (toward the trebel F hole) the post is, the weaker the coupling between the bridge foot and the back movement.  I might even try slanting the post slightly, to get the post position on the back even farther toward the trebel rib.  This of course requires someone who knows how to fit a soundpost.

 

Another possiblity is chinrest mass.  The chinrest moves slightly in the B1- mode, so a heavier chinrest will lower the frequency and amplitude slightly.  A lighter chinrest may move the frequency above open A, but the amplitude might get stronger.

 

One last possiblity is to use a non-radiating resonator trick.  There aren't many options for 440 Hz; about the only one I know of would be tuning the lower end of the tailpiece to resonate at 440, by adjusting the length of the tailgut.  I don't like this very much, as it is very tedious to get it matched up just right, and it can move around if the tailgut stretches or if different strings are used.  When it is not in perfect alignment, things can be even worse (plus you then lose the option to adjust the string afterlength).

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Wow! I had no idea I'd be getting such a thorough analysis, really appreciate it.

I didn't know it was going under some sort of spectrograph, otherwise I'd have been more consistent in the bowing for you. I did lean on the A note a bit to sort of accentuate the problem in the example, which I imagine has squeezed up the db.

I've checked the soundpost which was fitted recently, and it appears to be in the standard position. So I take it some form of soundpost tweaking should be able to shift this when I take the violin to be looked at? Is it worth considering a new bridge also? The last time someone looked at the violin I was told the bridge is a bit light. It's a Teller German bridge.

Honestly, this is all new to me so I've found it quite fascinating with all the new information I've learned over the last couple of days. I've also read about the regraduating and revoicing of violins, again something I was totally unaware about.

Is that also something possibly worth looking at? It's a late 1800's German trade, but from what I've been, a nicely made one. It has all 4 corner blocks fitted (as opposed to just the bottom 2 - or none at all) & an actual bass bar that's been carved tidily. On top of that, the wood is very attractive, the spruce is tightly grained and the maple would look at home on something far more expensive. It's also quite sentimental to me, so all things considered, I'd quite happily pay a bit of money to shift the horrible A resonance elsewhere!

Big thank you to everyone who's chimed in, I've found it very fascinating to read.

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Thank you Lars

...

I had the soundpost shifted and a new wittner tailpiece put on about 2 months ago and I'm almost certain that's when it began, although I could be mistaken. I've been trying my hardest to remember if it's something I've noticed before or not.

What about the tail piece resonance. You said that you changed the tailpiece to a Wittner one. I haven't used that kind of tailpiece so this is speculation but A=440 Hz is actually 4x110 Hz, if the tailpiece is heavy due to the four fine tuners you could get a B1- reinforcement through the tailpiece harmonics. If you still have the old one try to put it back because typically the tail piece resonance lies slightly higher at say 120 ... 140 Hz which doesn't cause interference with B1- . Alternatively you could add some Blue tack under the tailpiece to lower the resonance further. Just a thought. 

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 this is speculation but A=440 Hz is actually 4x110 Hz, if the tailpiece is heavy due to the four fine tuners you could get a B1- reinforcement through the tailpiece harmonics.

 

Sorry, no.

Tailpiece resonance at these lower frequencies are rigid body modes, sprung by the strings and tailgut.  There is absolutely no effect on higher frequencies, at multiples of the mode frequency or otherwise.  Also, tailpiece resonances will act as vibration absorbers, reducing rather than reinforcing sound output (to be precise, there is actually a slight reinforcement immediately above and below the tailpiece resonance, but the major effect is to create a big dip in the middle).

 

Bottom line:  I am 100% positive we are dealing with an exceptionally strong B1- resonance of the body, and looking for ways to mitigate the problem.  A very bad soundpost position and/or fit, or playing without a chinrest (or a light one)  could be contributing to the severity of the resonance.

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Sorry my responses came through so late, they're there if you read up.

I'm travelling up 70 odd miles or so over the next week or two to a restorers/repairers to have them take a look at it. Armed with what you've now told me, I can go in well informed.

I'll keep everything updated here. It does make me wonder though, if the original soundpost was shorter than usual, I imagine the violin was previously setup in lieu of the odd wolf note; and having had it replaced and returned to neutral has set this off!

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Try a few different chinrests, as long as you're at a shop.  Chinrests can sometimes have very strong influence on this particular resonance, not necessarily in any easily predictable way... you just have to try some and see.

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Hi Jim,

I had exactly the same problem on my #2 violin which was modelled after a Guarneri pattern. The open A was causing the lower bout below the treble F-hole to vibratrev excessively as I believe the plate was too thin there. People add masses to the plates to tone down these resonances. Since mine was still in the white I ended up coating with Vernice Bianca, which acts as a sealer coat and at the same time gives the plate extra stiffness, and the problem went away.

Are you sure there is not an over active area on your top plate? It seems some extra plate damping may be required in a critical spot. They make a magnetically attached weight which has been discussed in other threads.

http://www.maestronet.com/forum/index.php?/topic/319840-resonance-modulator-for-violin-viola-cello-and-bass/

Cheers,

Joe

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I have done some experiments with shoulder rests that could influence the wolf tone. I have two different (chinese) wooden shoulder rests that clearly influence the tone of the instrument. The one I use obviously is fairly OK and the one I don't use changes the tone.

 

I have done some measurements of the B1- resonance with the latter shoulder rest and it is very easy to see that it moves the B1- a lot depending on how it is attached and what the clamping force over the bottom plate is.

 

If you haven't done it already try to attach a shoulder rest at different angles over the bottom plate and also adjust the width of the shoulder rest to change the "clamping force". My feeling is that if tuning the violin down seemed to help then this could be a working solution to your problem. It could also be a good idea to try several types shoulder rests in a shop because they dampen the violin in different ways.

 

I'll post some pictures later.

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Measurements of the influence of the shoulder rest on the B1- resonance. The shoulder rest as such will influence the B1- resonance but perhaps more important is how close to the widest part of the lower bout the clamping is applied. It looks clear that a B1- shift of 10 Hz ... or more is possible.

 

shoulder_rest_good.png?w=450

Using my ordinary wooden shoulder rest puts B1- at 439 Hz. The instrument is work in progress so resonances will still change.

 

shoulder_rest_other_initial.png?w=450

Another shoulder rest moves B1- to 435 Hz when simply switching the shoulder rests.

 

shoulder_rest_other_final.png?w=450

 

After making the shoulder rest feet wider and thus clamping closer to the centre of the lower bouts the B1- resonance moves to 429 Hz. My feeling is that I could move it still more.

 

Clamping the bottom plate close to the widest part seems to lower the B1- resonance significantly. Please check this out and report back :) .

 

I made a blog post in Swedish regarding this adjustment here: http://larsil2009.wordpress.com/2014/06/11/fiolbygge-experiment-med-omojligt-material-9/ .

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Thanks for the replies everyone.

I've tried with a side mounted rest, no rest, and the Guarneri rest that's my regular on this violin. It doesn't seem to be making any difference.

The bass side seams are opening next to the bottom of the f hole. About a half inch or so in each direction, I'm not sure if that would make much difference, but it's something I only just noticed.

Also, I spoke to the luthier who sold me the violin and he's going to have a look at it for me. When I mentioned to him that the soundpost had been changed by another luthier because the post was too short, he was a little concerned. He insisted there's not a chance he would've fit a short post.

I'm taking it up out of town to be seen in a couple of weeks and I'll report back with how I get on.

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I promised to keep this updated.

Finally got out of town to take the violin back to the dealer/luthier who sold me the instrument. Happy to say it's been fixed, bass side back seams we're re-glued, fresh strings put on. But the actual issue was being caused by the bridge for whatever reason. He first used a temporary bridge to isolate that was the problem, the cut me a new French aubert bridge. The overly resonant A string, honking sound has gone. The string now balances with the others and can be played fine piano without the instrument tensing up and the bow wanting to glide off the string.

There's a very light harmonic overtone left, which I've noticed on a few other violins I've played before so I'm not very concerned about that.

Thank you to everyone who offered up their time and expertise.

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