Body size on 3D printed ukulele

[jwnicholson]

So it feels a little odd that I'm posting in a Luthier's forum on 3D printing ukuleles, but here goes I recently designed a 3D printed ukulele. In the process of designing it, I did a lot of Googling on different design aspects of ukuleles, with the results of the searches often leading me to this forum, where I learned a ton of valuable information. Said information helping me immensely in my design.

Now I'm back with my first question here. One of the cool things about 3D printing is the range of materials available, including transparent ones. I got it into my head that I wanted to next design a transparent uke with LED lighting. I've finished the first prototype (in the picture below), and I'm pretty happy with the way it looks:



The problem is that the sound is fairly quiet compared to the non LED lit version. I'm wondering if the internal box with batteries and LED's, which is fairly large compared to the size of the body, is why it's so quiet, and my question is if it's a simple matter of making a corresponding increase of the body volume to offset the volume taken up by batteries and LEDs? Or are there more complex considerations that I need to take into account?

In case you missed it, I posted in the New Member Introductions not too long ago a video of a sound demo and build process for the 3D printed uke, which I've pasted below. Thanks in advance for your help.
Jeff

 

[de Houtwinkel]

What electronics are you using?

 

[jwnicholson]

What electronics are you using?

Under the saddle piezo pickup from Musiclily. I'm actually surprised that the pickup output sounds better than I expected. It's the acoustic volume that's fairly quiet.

 

[de Houtwinkel]

Once you plug in, it doesn't matter what's inside the instrument. But if you are particularly looking into acoustic properties....the Helmholtz resonances may be something to look at. Importantly though is wood acts much differently than plastics.

 

[jwnicholson]

Once you plug in, it doesn't matter what's inside the instrument. But if you are particularly looking into acoustic properties....the Helmholtz resonances may be something to look at. Importantly though is wood acts much differently than plastics.

Thanks. I started looking into Helmholtz resonances. There's a lot of information there. I was hoping before diving in someone could tell me if need to calculate resonances or if, in a like to like comparison where body size and material is kept the same, but one uke has a battery block inside it, it's enough to simply compensate by increasing the body size. Or if it's not and I do need to start calculating resonances.

 

[hoji]

I would bet the lack of sound is due more to the extra weight than the air volume. Also could be the degree of elasticity in the filament used. You want light and stiff as possible.

 

[jwnicholson]

I would bet the lack of sound is due more to the extra weight than the air volume. Also could be the degree of elasticity in the filament used. You want light and stiff as possible.

The battery box isn't in contact with the front or the back of the body. Would the weight of it still impact the sound in that case?

The type of filament definitely makes a difference. I spent some time testing different filaments and trying to see how things like the bend modulus affect the sound.

But for a given filament the sound in a uke without the battery box is significantly louder than one with the battery box.

 

[de Houtwinkel]

The battery box isn't in contact with the front or the back of the body. Would the weight of it still impact the sound in that case?

The type of filament definitely makes a difference. I spent some time testing different filaments and trying to see how things like the bend modulus affect the sound.

But for a given filament the sound in a uke without the battery box is significantly louder than one with the battery box.

Weights are added to the sides in acoustic guitars to move the main node lines top resonance. I've never done that with ukuleles as making the sides stiffer seamed to always help that cause according to the data. Have you thought about 3d printing the body, but adding a wood top? I'd be interested to see the data and compare the two.

 

[jwnicholson]

Weights are added to the sides in acoustic guitars to move the main node lines top resonance. I've never done that with acoustics as making the sides stiffer seamed to always help that cause according to the data. Have you thought about 3d printing the body, but adding a wood top? I'd be interested to see the data and compare the two.

That's not something I have thought about. If I had any skills in woodworking I would have learned to make a traditional wood ukulele. I turned to 3D printing because I have zero abilities there

 

[de Houtwinkel]

That's not something I have thought about. If I had any skills in woodworking I would have learned to make a traditional wood ukulele. I turned to 3D printing because I have zero abilities there

I teach people with no experience how to make instruments, nothing is impossible

 

[jwnicholson]

I teach people with no experience how to make instruments, nothing is impossible

That sounds like something that I would really like to do! When the kids go off to college in 6 years and I retire and have more free time Future goals!