Bass bar question

[Kallie]

Hi there,

 

Im currently repairing a nice German violin, and I noticed the bass bar measurements (From the center line to the side closest to the center line) differs with 8mm. Measuring from the center line to the closest side of the bass bar, it measures:  Upper = 10 mm, lower = 19 mm.

 

Is there a specific reason for a bass bar to be like this, and not parallel with the center line? Does this have a big impact on the sound? The top is also pretty stiff, not too flexible.

 

The bass bar is NOT carved into the top, like some cheaper German/Czech violins are.

 

Thank You.

 

[Addie]

The bar sits beneath the G-string, which is not parallel with the center line.

[Don Noon]

The standard answer is that the bass bar is angled slightly across the grain to lessen the chance that the top will split along the bar.

[Kallie]

Thank you Addie, sometimes I guess the simplest answer is the right one. And thank you Don aswell.

[Brad Dorsey]

... Does this have a big impact on the sound?...

 

I suggest that you conduct an experiment to answer this question and let us know the results.

 

Set up the violin with the bass bar as it is and play it enough to familiarize yourself with the sound.  Then, remove the top and the bar and fit another bar parallel with the center line.  The new bar should have exactly the same length, width, height, profile, stiffness, grain width, etc. as the one you took out to eliminate these as variables.  Glue the top back on exactly where it was before, set up the violin and play it again.  Compare the sound with the sound you remember from a few days previously.  Be sure you use the same bridge in the same position, and likewise with the soundpost.  Also the temperature and humidity should be the same for both playing tests.

 

My point is that I doubt there's any realistic hope of answering your question.

[Addie]

The standard answer is that the bass bar is angled slightly across the grain to lessen the chance that the top will split along the bar.

And the angle corresponds to... ?

 

Is the bar angled to prevent splitting, or is that simply a benefit of following the G-string?  Probably a rhetorical chicken-or-egg question.  

[Don Noon]

And the angle corresponds to... ?

 

Is the bar angled to prevent splitting, or is that simply a benefit of following the G-string?  Probably a rhetorical chicken-or-egg question.  

 

If you can find an explanation of why following the G string should be beneficial let me know.

As for angle, I just put it in by what looks good to me.  I'm sure there are numbers out there, if you want to be "precise" about it.  Courtnall & Johnson have some funny formula that makes no sense to me.

 

I recall some reports of experiments with angle on tone (Darnton?  Oberlin?)  and don't recall any big tonal differences.

[Carl Stross]

 

Is there a specific reason for a bass bar to be like this, and not parallel with the center line? Does this have a big impact on the sound? The top is also pretty stiff, not too flexible.

 

 

Great question ! I hope David or Roger or Jefferey will give us a couple of good pointers.

[Addie]

If you can find an explanation of why following the G string should be beneficial let me know.

 

Why? No.  Strad did it that way, as far as I know.  Savart messed around with placement around 200 years ago, and we still put the bar more or less under the G-string.

 

The formula is fairly simple, but I get the same result just using the offset measurements.  

[David Burgess]

The bar sits beneath the G-string, which is not parallel with the center line.

Then should the bar take a bend at the bridge, to continue following the G string?

[Don Noon]

 we still put the bar more or less under the G-string.

I'm not saying it's wrong to have the bass bar "more or less under the G string", but I still think the reason for the angled placement is the splitting issue, not the fact that the G string is over there.

[Michael_Molnar]

I heard from a few knowledgeable makers that the bass bar angle was to prevent splitting like Don says. Again as Don says, I remember hearing an acoustical reason, namely to spread the bass bar vibrations along more annular rings. I believe Michael Darnton ran some experiments on this.

[curious1]

The bar sits beneath the G-string, which is not parallel with the center line.

That reminds me of the story of two guys on a bus. One of them gets off the bus and robs a bank. Later the police arrest the other guy as his accomplice.

The bass is mostly there to stiffen the top length wise in its lowest modes. You could leave the top really thick all over but then it would perform poorly at the higher modes.

The grain crossing does prevent cracking along the grain and that's a good reason to angle it. But I think the angling has as much to do with the general geometry. If you started with a square plate with a bar running 1/3 from the edge and then constrained the various dimensions until it looked like a violin it would be angled the same way we put a bar in usually.

[Will L]

All of the following is from Karl Roy, who has a worthwhile habit of discussing the history of violins going way back.  He says that the attached bass bar of today came into being between 1550 and 1600, and existed side by side (not literally) with the integral bar, which disappeared in the 18th century.  

 

There have always been different opinions about measurements.  

 

Count Cozio stated several things, one of which shows that the idea of springing the bar was already known in his time.  

 

Several systems for positioning include having the bar follow the angle of the strings; having it follow the angle described by the widest parts of the upper and lower bouts; and adjusting the angle the width of the bar based on whether the top is soft or 1/2 the width of the bar if the top is hard.

 

In every case, the bar needs to be in relation to the bass foot of a centered bridge.

[Addie]

Then should the bar take a bend at the bridge, to continue following the G string?

If the bar is 1 or 1.5 mm inside the bridge foot, the CL of the bar will be about underneath the string, won’t it? Or the string will be over the inside edge of the bar?

 

I don’t KNOW the answer, I only regurgitate what I read.  I’ve only done a few bass bars, and I did them “by the book.”

 

It seems to me that a lot in violin making is assumed, but we can’t really prove why, only what.  There’s a lot of   too.  

[captainhook]

I thought this was the only way to install a bass bar. Am I wrong?

 

[Will L]

Funny how I have never in my life realized that, intentionally or not, a bass bar IS pretty much under the G string.  Hey, stay with Maestronet long enough and look what you discover.

[Addie]

I thought this was the only way to install a bass bar. Am I wrong?

 

curved bar2sm.JPG

 

While it does address several theoretical issues, I don’t think it will catch on.  

 

I have seen one (on my bench) that was angled towards the center at the bottom, but my favorite so far was posted on another forum: it was just a little nub that made it look like there was a bar, when viewed through the sound hole.   

 

That definitely gets the  award.

[curious1]

While it does address several theoretical issues, I don’t think it will catch on.  

 

I have seen one (on my bench) that was angled towards the center at the bottom, but my favorite so far was posted on another forum: it was just a little nub that made it look like there was a bar, when viewed through the sound hole.   

 

That definitely gets the  award.

"it was just a little nub that made it look like there was a bar, when viewed through the sound hole"

That nib could work just fine in the right situation. For example: the only remaining original del Gesu bass bar, in the pochette "Fountaine", is cut on the slab. There is an existing original Pietro of Venice bass bar cut on the half slab and parallel to the center joint. Petherick describes the bass bar in a late del Gesu as cut on the slab.

How many of you are putting your bass bars in on the slab?

My point is that we have developed our bass bar shape and placement probably for maximum efficiency but there are other perfectly adequate ways to fit a bar for a given situation.

That nib might be called a proto bass bar but it sounds like it added stiffness at just the right point.

[Conor Russell]

 

 

That definitely gets the  award.

 

 

Oi! Not so fast!

[actonern]

^{Although I can't find it with the search engine, I remember some threads here in which it was suggested that a bar placed parallel to the centre line had the best sound, but at risk of a bar crack.  I took from this that if your top plate grain orientation (they wander sometimes) allows for a bar without inclination that still crosses a number of annual growth rings... do it.}

[martin swan]

What about the "barre d'harmonie rationnelle" that was an option on upmarket Laberte violins?

A bit like selling a violin "with added sprucification".

[Blank face]

There are many questions similar to this: Why has the violin corners? Why has it a scroll, not a hook or a ball? Why are the soundholes F-shaped? Why a 3-stripe purfling? Why (.....)???

They were thousands of experiments and improvers, but it all failed, and the reason is, IMO, that the design of all parts is the result of some hundreds years of developement, and now we are used the actual appearance and sound, with all internally and externally details. If you change one of this details, you're going to change it all.

Violin players and makers are very dogmatic people.

[Michael_Molnar]

Anyone experiment with different woods or material for bass bars? 

 

Mike

[Kallie]

While on the topic of bass bars, can someone perhaps shortly (or long if you want to) tell me what is meant by springing the bass bar? A picture would also be most helpful. I tried finding a picture myself, but no luck.