Bass Bar

[pativarius]

I was wondering if anybody has any basic thoughts on the bass bar. Not so Much about spring or no spring, but such things as how the different heights or thickness can change the sound and in what way. For instance, if you were making a viola and wanted to get the biggest sound on the bottom, would that require a taller and thicker bass bar, or a shorter and thinner. I know this is very general, but I think it is important. Also what about the shape, how can that affect it. Any thoughts would be great, the more general, the better.

[~ Ben Conover]

If you make a viola and then fit and test 5 bass bars of different shapes and sizes cut on the slab and on the quarter from split sawn old and new spruce and pine, then be sure to record the details !

I do my bass bars with the Sacconi measurements, no spring, split bars, chalk, etc. Nothing exciting I'm afraid, but they fit and they work.

http://www.flickr.co...in/photostream/

[Don Noon]

I have cut bassbars down from 16mm (incl top) to 13mm and less, and the difference in sound has not been anywhere near what you might expect given the cube power of the stiffness with height. A little more responsive and louder in the low-mid frequencies, but not much else. Others with more experiece might want to say something.

[David Burgess]

I have cut bassbars down from 16mm (incl top) to 13mm and less, and the difference in sound has not been anywhere near what you might expect given the cube power of the stiffness with height. A little more responsive and louder in the low-mid frequencies, but not much else. Others with more experiece might want to say something.

One of the most interesting bass bar experiments I was exposed to involved a violin with an externally mounted bass bar. This allowed trimming the bar, and trying the violin again very quickly, before memory had faded, and without introducing other variables. I too was surprised at how much wood could be removed, without causing huge changes in the sound of the fiddle. Not that there wasn't a "best" trim, depending on one's perspective.

Maybe Marty will comment, since he put that experiment together.

[Wolfjk]

I was wondering if anybody has any basic thoughts on the bass bar. Not so Much about spring or no spring, but such things as how the different heights or thickness can change the sound and in what way. For instance, if you were making a viola and wanted to get the biggest sound on the bottom, would that require a taller and thicker bass bar, or a shorter and thinner. I know this is very general, but I think it is important. Also what about the shape, how can that affect it. Any thoughts would be great, the more general, the better.

Hi,

It is very difficult to give a direct answer to your question! How the bassbar works, depends on many different aspects of your intstrument; plate thickness, shape and size of your FFs, the wood between the FFs, density of your plate, size of your viola, and many other factors, including the inner nick of the f-holes!

[polkat]

Not trying to hijack this thread, but along with pativarius's questions, I'm also interested in what effect a slightly shorter then standard (or longer for that matter) bar might have on tone? Certainly a shorter bar would somewhat limit support for the top, but the effect on tone?

[Jerry Lynn]

One of the most interesting bass bar experiments I was exposed to involved a violin with an externally mounted bass bar. This allowed trimming the bar, and trying the violin again very quickly, before memory had faded, and without introducing other variables.

Was the bar fit in the "normal" location?

[David Burgess]

Was the bar fit in the "normal" location?

No, it was on the outside.

Sorry Jerry, hope I can mess with you since we know each other a little bit.

From a quick look, aside from being on the outside, it appeared to be in a conventional location.

[Oded Kishony]

it was a really clever idea but I wish some way could have devised so that the bridge foot was supported, rather than having the the upper part of the bridge resting on the bass bar. I was always troubled by that bit.

Oded

[Jerry Lynn]

No, it was on the outside.

Sorry Jerry, hope I can mess with you since we know each other a little bit.

From a quick look, aside from being on the outside, it appeared to be in a conventional location.

HA. I would have expected something more creative from a person of your advanced age You can mess with me all you want David and unlike skywalker, I won't pummel you with water balloons.

I was just wondering how the bridge worked with the bar on the outside.

In my own observations I've found that shorter bars tend to give less resistance to the bow arm, which can be good for players who can't "drive" the instrument. Tonally, it seems to make little difference.

Edit: I see Oded answered my question.

[David Burgess]

it was a really clever idea but I wish some way could have devised so that the bridge foot was supported, rather than having the the upper part of the bridge resting on the bass bar. I was always troubled by that bit.

Oded

Since one side of the bridge needed to be cut away to fit on top of the external bass bar, it would have been better if we had checked the "rocking mode", and altered the bridge as needed to end up at around a normal value of 2700 to 3200 hz.

So many things to cram into one week.

Loved those "Acoustics Workshop" guys, and miss 'em, now that we're not scheduled at the same time any more.

[Skywalker]

HA. I would have expected something more creative from a person of your advanced age You can mess with me all you want David and unlike skywalker, I won't pummel you with water balloons.

What?!

...why, if I had a couple of water balloons right now...tell you what...

[DBurns]

I have cut bassbars down from 16mm (incl top) to 13mm and less, and the difference in sound has not been anywhere near what you might expect given the cube power of the stiffness with height. A little more responsive and louder in the low-mid frequencies, but not much else. Others with more experiece might want to say something.

Is it possible that the bass bar is already way too stiff, so trimming isn't really doing much?

Does a top without a bass bar move that much when strung up?

[Don Noon]

Is it possible that the bass bar is already way too stiff, so trimming isn't really doing much?

Does a top without a bass bar move that much when strung up?

I haven't done that test, but my guess is that even if it didn't move too badly when strung up, it would creep like mad to an unacceptable degree. There's visible distortion after a while with normal bass bars, so I don't think I'll go barless.

[Bill Warren]

I have cut bassbars down from 16mm (incl top) to 13mm and less, and the difference in sound has not been anywhere near what you might expect given the cube power of the stiffness with height. A little more responsive and louder in the low-mid frequencies, but not much else. Others with more experiece might want to say something.

This may explain my last violin's very nice and loud low end sound. It is the best one yet in terms of tone and it has wonderful G and D string sound (Dominant strings). I thicknessed (thinned) the top according to the Titian Strad specs, then thinned it some more until it weighed right at 60 grams (thinner than I have ever done a top). A normal (for me, 8 grams) bassbar raised the mode 5 taptone too high, so I cut that bassbar down thinner, more tapered, and lower, until it weighed 5 1/2 grams. That 5 1/2 gram bassbar may still be a little heavy by some standards, but I stopped cutting when I got the M5 taptone about a halftone from the back's M5 taptone. It seems that making the plates thinner reduced the "shrillness" and making the bassbar thinner and less tall boosted the low end tone. I haven't got the tone I want yet, but this violin is a big step closer to it, plus this violin starts a smile on my face to hear it...

[Don Noon]

8 grams for a bass bar is a real log; even 5.5 sounds excessive. In Curtin's taptone article, all of the bars were between 4 and 4.5 grams. Mine generally come out in that range too, but sometimes I'll go below 4 with a low-density bar.

[Bill Warren]

8 grams for a bass bar is a real log; even 5.5 sounds excessive. In Curtin's taptone article, all of the bars were between 4 and 4.5 grams. Mine generally come out in that range too, but sometimes I'll go below 4 with a low-density bar.

I was reading that same article (Curtin's taptone article). My top's M2 and M5 taptones are very, very close to those of the Kreutzer Strad - I quit cutting away the bassbar when I got my top's M5 taptone very close to the Kreutzer top's M5. If I had lightened the bassbar any more, my top would not have taptones almost like the Kreutzer Strad. I also split my top's M2 and M5 by 9 1/2 tones, since I noticed that interval on several of the tops in that article. So far, I am thrilled with the result of this latest "tonal experiment" of mine. I was absolutely NOT thrilled with my last tonal experiment, which was with Carleen Hutchins bi-tri octave tuning.

[Don Noon]

So far, I am thrilled with the result of this latest "tonal experiment" of mine. I was absolutely NOT thrilled with my last tonal experiment, which was with Carleen Hutchins bi-tri octave tuning.

Yes, I believe it is much better to work to a design that is known to work good, rather than to some numbers that are not proven by theory or statistics to do anything beneficial.

[Michael_Molnar]

Yes, I believe it is much better to work to a design that is known to work good, rather than to some numbers that are not proven by theory or statistics to do anything beneficial.

AMEN!

[Addie]

So when people blame poor low-end tone on a weak bar, is that just

[NewNewbie]

I was absolutely NOT thrilled with my last tonal experiment, which was with Carleen Hutchins bi-tri octave tuning.

You are not in a minority here.

It might be worth your effort to one a thread asking for others reports on 'bi-tri octave tuning' and what the results were.

Yet the Stradivari plate that exhibited this tuning scheme sounded great sic.

Perhaps something is a miss?

To tune or not to tune, that is the question:

Whether 'tis Nobler in the mind to suffer

The Slings and Arrows of outrageous Fortune,

Or to take Arms against a Sea of troubles,

And by opposing end them: to die, to sleep

No more; and by a sleep, to say we end

The heart-ache, and the thousand Natural shocks

That Flesh is heir to? 'Tis a consummation

Devoutly to be wished. To die to sleep,

To sleep, perchance to Dream; Ay, there's the rub,

For in that sleep of death, what dreams may come,

When we have shuffled off this mortal coil,

Must give us pause. There's the respect

That makes Calamity of so long life:

For who would bear the Whips and Scorns of time,

The Oppressor's wrong, the proud man's Contumely, [poor]

The pangs of despised Love, the Law’s delay, [disprized]

The insolence of Office, and the Spurns

That patient merit of the unworthy takes,

When he himself might his Quietus make

With a bare Bodkin? Who would Fardels bear,

To grunt and sweat under a weary life,

But that the dread of something after death,

The undiscovered Country, from whose bourn

No Traveller returns, Puzzles the will,

And makes us rather bear those ills we have,

Than fly to others that we know not of.

Thus Conscience does make Cowards of us all,

And thus the Native hue of Resolution

Is sicklied o'er, with the pale cast of Thought,

And enterprises of great pitch and moment, [pith]

With this regard their Currents turn awry, [away]

And lose the name of Action. Soft you now,

The fair Ophelia? Nymph, in thy Orisons

Be all my sins remembered." - Willie Shakes