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My small price 3D printed spherical speakers

Mike123

Active Member
Joined
May 31, 2020
Messages
130
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122
Location
Ukraine
After reading this and several other threads, I decided to make my own 3D-printed computer speakers. I don't have a 3D printer, so I used some friends' design and printing services. But no one had ever done such a large project before, so it was interesting to everyone.

The project's initial specifications were:
1. I wanted to do something exciting, get away from reality, and calm my nerves :-)
2. The finished product should be inexpensive by Ukrainian standards.
3. The speakers should be durable and long-lasting.
4. The speakers are tailored to the specific room, taking advantage of its unique features.
5. It's preferable to use speakers without a subwoofer.

The Lavoсe driver manufacturer has been popular in Ukraine for several years. I don't know if there's anything Italian about this company other than the name. But they produce good quality speakers with the necessary documentation. I've already had the opportunity to see this for myself. So, when the Lavoсe CSF051.21 driver became available, I decided to use it to create spheres. Moreover, this speaker already contains a built-in crossover, making manufacturing easier.

Features of the sphere:
1. It is large enough to fully utilize the driver's capabilities. The outer diameter is 285 mm.
2. Due to the power supply in Ukraine, it is highly recommended not to exceed a printing time of 12 hours. Otherwise, the risk of damaging the printed parts is very high. Providing a guaranteed power supply for longer is quite problematic.
3. An easily removable port is highly desirable, allowing for fine-tuning the sound on-site or reconfiguring the speaker for use with a subwoofer.
4. The sphere should be free to rotate in three planes for easy installation in the desired direction.

Therefore, it was decided to print the speakers from 10 parts: 8 sphere segments, a port, and a stand. Attaching the speaker with screws at the front and the port at the rear increases the strength of the glued segments. The printing material is PETG. The color was chosen to be brown to match the table's color.

The filling density is 60%. Somewhere online, I found information that this density filling makes PETG similar to MDF in acoustic properties. To what extent this is true, I don't know. But the sphere turned out very strong and heavy.

And now the work has really begun :-). In total, the speakers took about 4 weeks to produce. The photo shows the rear and front segments. They took 12 hours, 6 minutes, and 12 hours, 26 minutes to print, respectively.
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Wooden furniture dowels were used to connect the sphere parts. The gluing was done with epoxy glue. The final sealing of the seams and cracks was done with PVC dispersion. First, the two hemispheres were glued together, then they were covered with 2 mm thick butyl rubber. After this, the final gluing of the sphere was performed.
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After assembling the first sphere, it became clear that the glue seams on the front were not very aesthetically pleasing. Therefore, an 11th piece was added – a decorative ring matching the driver color.
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The stands are mounted on soft silicone feet. The sphere is mounted on sealing gaskets that allow it to rotate in its mounting location in any direction.
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Since the left and right sides of the table are at different levels, we had to print one more part—a 100 mm extension cable—in one copy.

The resulting costs were:
6 kg of PETG filament - $60
2 Lavoce CSF051.21 speakers - $72
Wires and connectors - $10.
Total cost for two speakers is about $150.

So, it all looks something like this:
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Now, impressions and measurements. I'll say right away that I had no illusions about these speakers and didn't expect any miracles. The reality turned out to be quite good. These are measurements taken 2 cm from the tweeter.
spl.pngthd.png
Firstly, the drivers have very low distortion, generally around 0.5%. Secondly, the built-in crossover does its job perfectly and is well-matched. The slight high-frequency boost didn't bother me at all. And the attenuation over distance will reduce this boost. And the speakers sound cheerful and optimistic :-)
spl -1m.png
At one meter, room modes began to influence the sound. However, the frequency response remained fairly flat.

The frequencies below the resonant frequency caused the most problems. I was well aware that this driver was designed to be supported by a subwoofer. But I didn't want to build a subwoofer, so I tried to squeeze everything out of the speaker, using room modes and placing the ports close to the wall.
The resulting low frequencies from both speakers at the listening position look like this:
LF-LR.png
The result was mixed, but not annoying. There is bass, but it is colored and uneven. This adds a certain uniqueness to the sound and prevents these speakers from becoming clones of the full-range, large speakers in the same room. For YouTube speakers, the sound is very pleasant and non-irritating, even over several hours of continuous listening. Therefore, the subwoofer project has been postponed indefinitely. And so far, everything has turned out better than expected. For now, I'm happily listening to my homemade computer speakers :-).
 
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Respect!
This approach was beyond my own imagination.
Why?
Coming from woodworking, I would build it up from basis to top in several stages :facepalm: .
To minimize it to similar pieces all over (coconut cuts) is a great transition of thinking an engineering (that is all around in UA, that is published here, and will inspire former technical progress, I'm certain).
Well done :)
 
To minimize it to similar pieces all over (coconut cuts) is a great transition of thinking an engineering (that is all around in UA, that is published here, and will inspire former technical progress, I'm certain).
It's been done before. :)

DeathStar2.jpg
 
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