Resonance Bar

[Jim Garber]

I know this is not a mandolin but the concept could work on a mandolin, if someone were so inclined.



I know that Joseph Bohmann, the crazed Chicago maker, used resonating metal rods in his violins, mandolins and maybe guitars, too. His patent is here.



I was going to add it to this Virzi thread but I think it is really a different concept.

[Timbofood]

I had visions of a saloon with a really good band!

[buckhorn]

here is a pic of the sound bar from a 1780s violin that that I saved from the wood stove.. the ends did not go all the way to the edges.. still giving enjoyment......

[Bill McCall]

I think the use of that type of bar (installed slightly differently) in a mandolin would be to reduce the string force trying to pull the tail block over the top (that may be a cause of the bulging that can occur between the bridge and the tail block). That bar would also seem to allow the top to have less compression force acting on it which might have a positive impact on the sound. It would also seem to allow lighter tonebars as their need to stiffen the top would be reduced. That would mean the top would have less mass which would seem quite beneficial.

Haven’t made an instrument like that to verify that notion but I’m sure someone has.

Just my random $.02.

[Charles E.]

here is a pic of the sound bar from a 1780s violin that that I saved from the wood stove.. the ends did not go all the way to the edges.. still giving enjoyment......

Typically the ends of violin bass bars terminate 40 mm from the edge of the plate.

[sblock]

here is a pic of the sound bar from a 1780s violin that that I saved from the
wood stove.. the ends did not go all the way to the edges.. still giving enjoyment......

You are confusing the bass bar, which is something that all violins have, with the "resonance bar" shown by the OP (Jim Garber) in a viola. There is virtually no credible evidence that "resonance bars" work to improve the sound or the acoustic efficiency, and that's why violins don't tend to have these.

[Jim Garber]

This is just another of off-ramp creations in the superhighway of luthiery that I find so very interesting. Actually the fiddle I play designed by a Brooklyn patent attorney around 1915 have a dowel stick running down the center but i think that that serves more to reinforce the structure of the instrument than to influence the sound.

There is virtually no credible evidence that "resonance bars" work to improve the sound or the acoustic efficiency, and that's why violins don't tend to have these.

Of course, the same could easily be said about Virzi tone producers, double topped instruments and the oddball Gelas instruments, yet people still make them. I found this viola on the rarities page of this violin website. Take a look at the other oddballs they have there. A few pictures below.