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Andreas Preuss

Purpose of tuning the fingerboard

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11 hours ago, David Burgess said:

Both seem (to me) like rather low resolutions, to see detail. My opinion is that details matter, but I could be wrong.

Peter, is that a smartphone app you are using? if so, which one is it and how much does it cost?

The software has a lot of modules,  but for $19.90 you have what you need to do FFT analyses.

http://www.studiosixdigital.com/audiotools-modules-2/the-audiotools-platform/cyber-monday-sale-pricing.html

 

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35 minutes ago, Andreas Preuss said:

Thanks everyone for contributing to this thread. 

For all what I read so far, adjusting the fingerboard makes rather minimal changes in the sound. It is more like flattening out with a scraper an unevenness only visible under a bright lamp. 

So for all possible sound adjustments it is rather at the end of the priority list.

Put it on the priority list of player feel, IMO it is quite high on that list. Even a bad player like me can recognize this "enhancement" when this switch is on.

It's not so audible on soft fiddles with low dB body modes.

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6 hours ago, ilovefiddle said:

 

Hi David and Don,

how about the sound between the side mount / across the tailpiece chin rests? I feel the tonal characteristic quite different between these types of chin rests.

I can also notice the difference when I screw the chin rest harder (over the tailpiece type only). My illusion?

Not an illusion. I agree.

Not everyone will notice these differences. But that's how it goes with all kinds of things. Some perceptive abilities can be improved with practice and experience, but I think there also may be natural differences in sensory sensitivity.

Do the small differences matter? In my opinion, several small differences can add up to a significant change. If one can't perceive these individual small differences,  they aren't in a good position to arrive at the cumulative improvement. But it's also easy to fool ones-self,  and I have done that many times myself, thinking I'd "had an aha moment", and later realizing that the "improvement"  made no difference, or actually made things worse.

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2 hours ago, Peter K-G said:

Put it on the priority list of player feel, IMO it is quite high on that list. Even a bad player like me can recognize this "enhancement" when this switch is on.

It's not so audible on soft fiddles with low dB body modes.

Peter, thanks for your input. I'll definitely check it out on my next instrument. 

So in practical terms this means that I have to thin down the fingerboard until I reach the desired frequency, righy? What if the fingerboard reaches a kind of minimum thickness and I would need still reduce the thickness to reach the desired frequency?

What about the underside scoop? I prolong the machine made scoop until the neck heel like fading out. 

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11 minutes ago, Andreas Preuss said:

Peter, thanks for your input. I'll definitely check it out on my next instrument. 

So in practical terms this means that I have to thin down the fingerboard until I reach the desired frequency, righy? What if the fingerboard reaches a kind of minimum thickness and I would need still reduce the thickness to reach the desired frequency?

What about the underside scoop? I prolong the machine made scoop until the neck heel like fading out. 

That would be, of course not. The fingerboard is one of the player's most important part of the violin and should have the right dimensions. It's the underside part after the neck you work with. I could post some images later

You have about +/- 20 Hz to work with B0 on the fingerboard, but it is the neck together with fingerboard that matters and most important in combination with the sound box flexibility, mostly stiffness of the backplate.

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1 hour ago, David Burgess said:

Not an illusion. I agree.

Not everyone will notice these differences. But that's how it goes with all kinds of things. Some perceptive abilities can be improved with practice and experience, but I think there also may be natural differences in sensory sensitivity.

Do the small differences matter? In my opinion, several small differences can add up to a significant change. If one can't perceive these individual small differences,  they aren't in a good position to arrive at the cumulative improvement. But it's also easy to fool ones-self,  and I have done that many times myself, thinking I'd "had an aha moment", and later realizing that the "improvement"  made no difference, or actually made things worse.

The size of changes necessary in going from poor to mediocre, mediocre to good, good to great might get progressively smaller and harder and harder to perceive.

Making a small change to a poor violin probably won't do much good.  Making large changes to good violin might be a disaster.

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Sounds complex?

It really isn't, because it will more or less fall in place by itself if you are consistent when choosing fb blanks and make sound boxes within a certain stiffness range.

Think of A0 frequency, it's almost impossible to get it really off, if you have normal dimensions and use a known pattern/form

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41 minutes ago, Andreas Preuss said:

Peter, thanks for your input. I'll definitely check it out on my next instrument. 

So in practical terms this means that I have to thin down the fingerboard until I reach the desired frequency, righy? What if the fingerboard reaches a kind of minimum thickness and I would need still reduce the thickness to reach the desired frequency?

What about the underside scoop? I prolong the machine made scoop until the neck heel like fading out. 

 

31 minutes ago, Peter K-G said:

That would be, of course not. The fingerboard is one of the player's most important part of the violin and should have the right dimensions. It's the underside part after the neck you work with. I could post some images later

You have about +/- 20 Hz to work with B0 on the fingerboard, but it is the neck together with fingerboard that matters and most important in combination with the sound box flexibility, mostly stiffness of the backplate.

 

23 minutes ago, Peter K-G said:

Sounds complex?

It really isn't, because it will more or less fall in place by itself if you are consistent when choosing fb blanks and make sound boxes within a certain stiffness range.

Think of A0 frequency, it's almost impossible to get it really off, if you have normal dimensions and use a known pattern/form

Here is some more information

http://www.thestradsound.com/ongoing/tuningfingerboard

http://www.thestradsound.com/ongoing/checkingmodesandchoosingfingerboard

High ringing fingerboard (blank 634 Hz) -> Thick end:

FB_End_Thick.thumb.jpg.c92171a9c2adbe4daafd176418dc841d.jpg

Low ringing finger board (not used, will produce lower B0 dB) -> Thin end:

LowPerformanceFB_Discarded.thumb.jpg.6473861a5c17027d99ff769858f8b983.jpg

 

 

 

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15 minutes ago, ilovefiddle said:

Thank you David!

Do you have any “half-baked theory“ on this matter?^_^

Just that I don't find the neck-fingerboard-combination resonance to be as significant as Peter does, compared to the fingerboard itself. While the neck can ring like a bell when the instrument is free-hanging, it's very highly damped when the instrument is in playing position. The fingerboard isn't, until you get into the higher positions, when the fingers are pressing against the wobbly end.

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As more of a player than maker, I have to agree that there is something to these small adjustments or “tunings”. The way an instrument responds tactily to the player is as important as the sound. It is my opinion that getting the last five percent out of an instrument will matter in the hands of a good player. I think David Burgess is a good enough player to know what I mean. In the area of fingerboard tuning it is felt to some degree in how the instrument responds to bow input.

Players can be very fussy about string type, string height, etc. in addition to the sonic and responsiveness characteristics. Unfortunately this can also bias players that are evaluating a violin toward what they are used to.

Perhaps the real question is—is it worth it to the luthier in terms of time to get that last five or so percent? And if so, can they evaluate the feel and sound of an instrument by playing it? Will the fine tuning persist in various humidity and temperature changes?

These characteristics may not show up in FFT tests.

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7 hours ago, David Burgess said:

Just that I don't find the neck-fingerboard-combination resonance to be as significant as Peter does, compared to the fingerboard itself. While the neck can ring like a bell when the instrument is free-hanging, it's very highly damped when the instrument is in playing position. The fingerboard isn't, until you get into the higher positions, when the fingers are pressing against the wobbly end.

David,

I do not find the neck-fingerboard "that" significant! (except for maybe the player, who knows?, to me it does, but I'm a terrible player, too high and I feel the violin is "dry")

What I do know, is how to master all the modes below 600 Hz, without "odd" graduation, In fact graduations Strad like or DG like, does it matter,. I do not know yet.

The only thing I know so far, is that my violins are loader than average and that I can copy each of them.

B0 is just the the cream on top of the puddinng (and I have  no idea if I'm making sense in US English, just writing....)

Anyway, why not put B0 at A0, it will happen by itself, before you know it, or try not to, equally difficult!

And if not, you are far off, an old Italian!

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I have a really good sounding viola. It is made very light, with a light fingerboard with reduced thickness (many Degani violins have this). If I don't touch the neck the open A has a strong wolf. As soon as I touch the neck this is gone (this is why it took a while until I noticed that interesting feature). I then experimented with small weights - I used roofing lead with doublesided tape - to tune this fingerboard. And with an extra 2g of weight the wolf disappears. The overall sound character is not much influenced though.

I can try to get a spectrogram with and without the lead to identify how it shifts A0.

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1 hour ago, uguntde said:

I have a really good sounding viola.... If I don't touch the neck the open A has a strong wolf.

A wolf at open A (440 hz) has nothing to do with A0 or B0, which are much lower.  This is the B1+ mode, and adding mass to the fingerboard may shift the mode shape and frequency of the B1+ mode slightly to where the wolf is diminished.

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2 hours ago, uguntde said:

I have a really good sounding viola. It is made very light, with a light fingerboard with reduced thickness (many Degani violins have this). If I don't touch the neck the open A has a strong wolf. As soon as I touch the neck this is gone (this is why it took a while until I noticed that interesting feature). I then experimented with small weights - I used roofing lead with doublesided tape - to tune this fingerboard. And with an extra 2g of weight the wolf disappears. The overall sound character is not much influenced though.

I can try to get a spectrogram with and without the lead to identify how it shifts A0.

It will be interesting to see if your viola's A0 is at or near 220Hz.

 

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One final experiment with A0/B0 matching...

I took another fiddle in the shop that had B0 higher than A0, so I could tune it by adding mass.  This was what I thought was the ultimate way to examine the effect:  no strings or bridge, and take impact by tapping vertically on the bass bar.  This is the same direction as the fingerboard movement, so it should give the most excitation as possible to the fingerboard mode.  I also suspended the violin from a rubber band to eliminate as much damping as possible.  I took the data with the highest resolution on Audacity, then exported it for better plotting.  The A0 and B0 were matched at 285 Hz.

886337701_Tunedfingerboard285hz.jpg.0f67d7b8c0a6af7889d32f180ae17e0d.jpg

It's very similar to what I found before... maybe ~2 dB or so attenuation of the peak, and ~1 dB or so boost on either side, extending somewhere around 10 Hz to either side.  (Note: a semitone here is 15Hz)

I also recorded the fingerboard resonance in the suspended case and compared it to the position you'd need in order to play the A0 note:  hand on neck, finger down on the C# (ish) location of where the G string would normally be.

1124997950_fingerboardvibrationsuspendedandnormalplayingpositionforCsharp.jpg.1b8a7c50429fb01695dceb8b259578f7.jpg

As expected, there is a lot more damping in the playing condition.

So, in this extreme test, the difference would be very minimal, and restricted to the fundamental frequency of the C# note on the G string, with perhaps very minimal effect extending a semitone either side.  It is important to recognize that the physics is clear that there will be no other effects anywhere else on the instrument, or at any overtones of these notes.  If you think it's brighter, more responsive, or something else, it can't be mode matching that's doing it.  

And, with the damping that comes with actually playing, the effects will be even less extreme that I have measured here.

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I don't believe anybody who says tuning the B0 to A0 helps their instruments.

But to be fair and unbiased I also don't believe anybody who says tuning the B0 to A0 doesn't help their instruments.  

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50 minutes ago, Don Noon said:

One final experiment with A0/B0 matching...

I took another fiddle in the shop that had B0 higher than A0, so I could tune it by adding mass.  This was what I thought was the ultimate way to examine the effect:  no strings or bridge, and take impact by tapping vertically on the bass bar.  This is the same direction as the fingerboard movement, so it should give the most excitation as possible to the fingerboard mode.  I also suspended the violin from a rubber band to eliminate as much damping as possible.  I took the data with the highest resolution on Audacity, then exported it for better plotting.  The A0 and B0 were matched at 285 Hz.

886337701_Tunedfingerboard285hz.jpg.0f67d7b8c0a6af7889d32f180ae17e0d.jpg

It's very similar to what I found before... maybe ~2 dB or so attenuation of the peak, and ~1 dB or so boost on either side, extending somewhere around 10 Hz to either side.  (Note: a semitone here is 15Hz)

I also recorded the fingerboard resonance in the suspended case and compared it to the position you'd need in order to play the A0 note:  hand on neck, finger down on the C# (ish) location of where the G string would normally be.

1124997950_fingerboardvibrationsuspendedandnormalplayingpositionforCsharp.jpg.1b8a7c50429fb01695dceb8b259578f7.jpg

As expected, there is a lot more damping in the playing condition.

So, in this extreme test, the difference would be very minimal, and restricted to the fundamental frequency of the C# note on the G string, with perhaps very minimal effect extending a semitone either side.  It is important to recognize that the physics is clear that there will be no other effects anywhere else on the instrument, or at any overtones of these notes.  If you think it's brighter, more responsive, or something else, it can't be mode matching that's doing it.  

And, with the damping that comes with actually playing, the effects will be even less extreme that I have measured here.

Great work Don

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1 hour ago, Marty Kasprzyk said:

It will be interesting to see if your viola's A0 is at or near 220Hz.

 

A subharmonic vibration can reinforce a harmonic vibration causing its amplitude to grow.

For example if my kid sits on a swing which takes 2 seconds to complete one out and back cycle its natural frequency is 0.5 Hz.  If I give him a good push at the top of his arc every 2 seconds  the height of his swing motion will get higher (resonance).

If I get pooped I can skip his every other out and back cycle and push only once every 4 seconds at the top of the arch.  His swing motion can still get higher even though my applied pushing is only half the frequency of the swings natural frequency.

In the similar fashion a viola with a A0 frequency of 220 Hz (typical violins are around this) can increase the amplitude of a 440Hz resonance which might cause a wolf note problem. 

Going back to the swing--if I skip another cycle and wait to push on every third one the same thing can happen if I push hard enough and so one with lower and lower subharmonic frequencies. 

If you don't pay attention you can get hit in the head and start making violas.

 

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Is it possible that tapping/ impact hammer/FFT tests don't give the full picture? Not saying that FFT is not valid and very useful, but do the tests fully portray the actual experience of playing an instrument? Perhaps fingerboard tuning is a "leap of faith"...

On a different subject, has anyone done FFT analysis with different string types/manufacturers on the same instrument? If so, is this also an "imagined" phenomena? If it is not a quantifiable variable, to me that either means that FFT is limited or I am living in one of Everett's other multiverses. If I get some time I will try such a test.

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7 hours ago, scordatura said:

Is it possible that tapping/ impact hammer/FFT tests don't give the full picture? Not saying that FFT is not valid and very useful, but do the tests fully portray the actual experience of playing an instrument?

FFT doesn't show everything which can be heard, or which can be seen from the waveform on a sound file. Heterodyne tones (Tartini tones), including various forms of additive and subtractive tones would be some examples. I suspect that these may be very important.

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12 hours ago, Don Noon said:

A wolf at open A (440 hz) has nothing to do with A0 or B0, which are much lower.  This is the B1+ mode, and adding mass to the fingerboard may shift the mode shape and frequency of the B1+ mode slightly to where the wolf is diminished.

Don,

Could you please elaborate on this? I just had a violin in for some repairs which involved taking the top off and it now has a wolf on the open A. I don't know if it had it before. You are saying that a weight added to the underside of the free end of the board might help or a stiffer or more massive FB? How much weight are we talking about?

Thanks

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1 hour ago, David Burgess said:

FFT doesn't show everything which can be heard, or which can be seen from the waveform on a sound file. Heterodyne tones (Tartini tones), including various forms of additive and subtractive tones would be some examples. I suspect that these may be very important.

Thanks for posting this David. At one point I worked on fingerboards on 5 or 6 instruments in one go. I recall that on two of them it had a tangible difference. On the others probably not as significant. Obviously there are many variables at play with a group of different instruments. Did not do any spectral analysis to validate it though.  

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11 hours ago, Marty Kasprzyk said:

A subharmonic vibration can reinforce a harmonic vibration causing its amplitude to grow.

--if I skip another cycle and wait to push on every third one the same thing can happen if I push hard enough and so one with lower and lower subharmonic frequencies. 

Not true.

Your pushing example works only because your "push" is not a true sinusoidal energy input, but an impulse... it has energy in the higher harmonics as well, which increase the amplitude of the higher harmonic resonances.  A pure 220 Hz input will do NOTHING to a 440 Hz resonance, and vice versa.  The mode is energized only if there is energy at (or very near) that frequency... and for slightly off-resonance energy input, the vibration will be at the frequency of the input, not the natural frequency of the mode.

9 hours ago, scordatura said:

On a different subject, has anyone done FFT analysis with different string types/manufacturers on the same instrument?

Normally the strings are damped during impact FFT readings, so they don't enter into the output.  Undamped strings make a mess of it.  For FFT of bowed response, you would get string influence.  I do take bowed response with different strings, but haven't done tests to specifically extract the string influence alone.

1 hour ago, nathan slobodkin said:

Don,

Could you please elaborate on this? I just had a violin in for some repairs which involved taking the top off and it now has a wolf on the open A. I don't know if it had it before. You are saying that a weight added to the underside of the free end of the board might help or a stiffer or more massive FB? How much weight are we talking about?

Thanks

Nathan,  on a viola, and A wolf would be the B1+ mode, and on a violin it's the B1- mode.  Details.  But in either case, it is a large-scale body mode, and almost everything on the instrument moves to some degree (except for nodal line zones).  The chinrest moves, so mass, location, and clamping pressure can have an influence.  Other flapping things, like tailpiece (particularly the end, as influenced by gut free length), chinrest overhung mass as on center-mount styles, or perhaps fingerboard twisting modes might get involved.  The normal B0 fingerboard/neck mode is far too low in frequency to have an influence here.

Things can get complicated.  A "before" state might have had a tuned tailpece resonance (intentional or not) as a wolf killer, and after re-assembly the mode matching is disturbed.  Unlikely, but possible.  Chinrest would be my first thing to look at. 

The "repairs" are also an influence that can change mode shapes and frequencies, as well as damping.  I have often found new instruments to have awful wolves which go away after settling in, so I would expect repairs to have somewhat of that effect as well.  Did you change the bass bar?

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12 hours ago, scordatura said:

Is it possible that tapping/ impact hammer/FFT tests don't give the full picture? Not saying that FFT is not valid and very useful, but do the tests fully portray the actual experience of playing an instrument? Perhaps fingerboard tuning is a "leap of faith"...

On a different subject, has anyone done FFT analysis with different string types/manufacturers on the same instrument? If so, is this also an "imagined" phenomena? If it is not a quantifiable variable, to me that either means that FFT is limited or I am living in one of Everett's other multiverses. If I get some time I will try such a test.

The tapping/impact hammer/FFT tests of the radiated sound is certainly important but it doesn't do much to help explain the feel of playing an instrument.

The admittance tests at the bridge done with accelerometers  or laser scanners are more useful for explaining playing issues like wolf notes and bow interactions (maximum and minimum bow pressures etc.).  Body motion like at the neck or chin rest affects the feel of the instrument and this doesn't show up on a FFT either.

I pointed out before that at the recent Indianapolis violin search that all 45 violins had laser scan admittance tests done on them.  Hopefully we might see some differences between the  final violins selected and those which weren't.

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