Generative Violin Bridge by OpenFabPDX


#1

So @dsp39 crerated a new type of bridge, yay!

Was wondering @dsp39 :

  1. What materials did you use to print it?
  2. How does the E string hold?
  3. If I want a 6 or 5 string one, is it possible to generate another? What tool did you use?
  4. How does it sound?

I wonder


#2

Good questions! Thank you for posting the design here.

  1. I’ve only printed them in standard PLA
  2. E string holds great!
  3. I used Autodesk Generative Design. Which, as of October 7th, should be available to any user of Fusion 360. Yes, you could generate a bridge for any number of strings.
  4. So it actually sounds pretty bad. I ran the design through modal analysis in Fusion 360 to check for harmonic modes. It has zero harmonics, which makes sense because the algorithm is optimized for stiffness. The sound is harsh and biting, I actually had no idea the bridge could have such a profound impact on the sound of a violin, at least an acoustic.

I would encourage everyone to try one! It’s very interesting to hear such different sound.


#3

Violin bridge is critical to sound.
With my Repstroh, I initially printed a bridge, then took that and cut blank to fit it. The wood made an audible difference. More “woody” timbre.
Its a pain that sending a violin to be fitted at a luthier is an expensive business. I think it would be helpful to understand what exactly they do. There is also lots of research, for example this one.

In your new acoustic you might also want to consider a sound post, and a bass sound post.

It might be interesting though to generate new bridges with different harmonics. but keep in mind the violin bridge did evolve for hundreds of years, including what material to use.


#4

Great points!

Yes, I think the bridge is likely more or less perfected to achieve clear tone and amplification. I do think there’s opportunity in bridge design to play with adding effects to the sound. That’s part of what I like about the generative bridge — it shows how a very different sound can be achieved by a simple change (and a very short print).

Thanks for the article! I haven’t seen that one and I’ll have to dig in. I read a lot of research papers before I made the ModFiddle. They were helpful, but more than anything what I took away is that we still don’t really understand what makes “the best” violins the best.

The article I found most clear and informative was this one by John McLennan. I collected the articles I found most useful. You can check them all out in this OneDrive folder.

Yes, the ModFiddle has a sound post and a bass bar. My first version did not, and it didn’t work AT ALL. It was crazy how much it didn’t work. I should have taken a video. Imagine the worst wolf tones ever for every note. It was clear that the instrument just wasn’t stiff enough to support any string vibrations.

Back to the bridge; any thoughts about how a bridge could add different and interesting sound?

If we think of the bridge as a mechanical filter and amplifier — what frequencies or sounds could we filter or amplify to change the sound?

I wonder — can we tune the resonant properties of each string? The generative bridge sort of branches into legs to support each string. What if we made those legs more extreme — could we shape them such that the best resonant frequencies of each individual string is amplified?


#5

I think you should think about amplifying either vertical and horizontal waves. The vibration from the bow is different form the ones coming form other sources.

Check this out (I tried to put the right time on the video):

The CR also has a switch which puts a high pass filter to remove any electronic garbage and the thumping of the bow Source.

BTW, I really suggest we start pulling these guys and get feedback from professional players. The facebook group I linked in the community page has quite a few people there who really know what they are doing.


#6

Yeah I like what you’re thinking.

I posted this in the ModFiddle thread, but you can hear the generative bridge compared head to head with a regular bridge in this video.