Violin Forum/Message Board

[Lemuel]

Fellow luthiers,

I would be interested in your comments after looking at this link.

http://www.bbc.co.uk/go/em/fr/-/news/science-environment-13573631

[DonLeister]

Hi Lemuel,

Those are interesting pictures, and though only one is of a violin, I have seen many similar ones for violins.
I think any given image would reflect something *extremely* specific given all the variables like arching, graduation, type of excitation, bowing, wood, strings, set up, bridge, post and on. And then the image is not sound either which is what is most interesting.
I have not found them particularly useful when it comes to making violins. I always want to start speculating about how a violin works when I look at them.

[Dave Chandler]

Makes sense the patterns would subdivide as you go up in frequency because of the shorter wavelengths. Also notice Carleen Hutchins name on the violin top. Google this name and "violin" and "accoustics" and see what you get!!
_________________
Dave in the Blue Ridge
Southern Violin Association

"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill

"I took the road less travelled, and now I don't know where I am." Marco Polo

[John Cadd]

Interesting detail is seen in the violin wings where the bassbar influence produces a more uniform spread moving outwards.Whereas the treble side wing lets the vibration turn as it travels downwards.

The UNSW research using Chladni mode patterns compares an old German violin with a factory "Lark" Chinese model. It`s like trying to understand Arabic handwriting.Only a few differences can be noticed.
In the UNSW site they show metal plates that have very similar patterns to the violin plates. There are a few untidy patches on the Chinese violin plates . Do these patches show up more in between the main node frequencies? Can any of these diagrams help a maker? Surely a Chinese factory can produce a wooden instrument of even thickness to compete with a simple metal plate. That`s not much of an acid test is it?

[John Cadd]

Having a second look , the wings are not so different as I thought. The node seems to stick to the bassbar on the treble end a bit before pulling to the side. The holograph details are much fuller than the tea leaves though. But this is a separate component. How do makers choose the best parts to copy? What happens if you pile all the images one on top of the other? They tried that idea with human faces recently.They worked out the average human face on Earth was a fairly typical looking Chinese guy. Have the Cardiff people tried to answer these difficult questions?

[John Cadd]

If each diagram was linked to thickness details and arching and then compared to other violins at the same frequency it might become more useful to a maker. That would be like a triangulation method to pin down useful facts.The facts are there but we can`t interpret them properly.