I have always loved the look of the old radio horns of the 20’s and 30’s, but sadly, acquiring them is becoming harder and harder these days, and when you do come across one, the price is usually very high. There are reproductions on the market in the form of standalone bluetooth speakers, but these are usually sold at an even higher price point than the originals.
I had almost given up on the idea of getting one of these until I had the aha-moment so many of us makers have at some point. I realized “Hey, I have a 3d printer, so why not just make one?” and so off I went to Fusion 360 to see what I could slap together.
Initially I was just going to make the horn part, and make a wooden base for it to house some electronics for a Bluetooth receiver and speaker, however, looking at my Echo Dot sitting at the corner of my desk, a light-bulb went off and the idea for the Gamazon was born!
The design is pretty straight forward, and is designed with the mindset of not needing to go out and buy any parts other than some paint, witch is of course completely optional. Just print, assemble and enjoy.
Monoprice Maker Select V2
0.1 mm and 0.2 mm
All parts except for the base and lid (which was printed at 0.1mm) was printed at 0.2mm using PLA on my modded Monoprice Maker Select V2 with a 20% infill.
These parts make up the neck of the horn and will need to be glued together. I have also included the whole neck as a single file if you would like to chop it up yourself.
This is the mouth of the horn and should print fine as one piece.
This is the ring connecting the neck to the mouth. Supports are recommended for this part.
This is the lid of the base which connects the neck to the base.
This is the base of the speaker, and doubles as the acoustic chamber channeling the sound from the speakers of the Echo to the horn.
This part is completely optional and is for sealing the hole where you slide the power cord through by slipping it onto the wire. In my testing I have not found using this part to have any benefits to the sound, but it does provide a cleaner look to the base.
Start by gluing the neck together using the pre-split pieces or, if you can figure out a way to print it, use the complete neck model provided.
Next, assemble the whole horn using the joint.stl file to hold the neck and horn together. It is recomended to use glue for this step as well, but not necessary as it should be a fairly tight fit.
Now that you have the horn assembled, you can either glue it to the lid or friction fit it.
I recommend just using friction to fit this part so that you won't have to print and repeat all previous steps if there is ever a major design overhaul to this project.
Push the power cord through the hole at the back of the base, and while the lid is still off the base, drop the Echo Dot into the lid from the top and connect the power cord to it.
NOTE: It is important that you do not glue the lid to the base/acoustic chamber, as doing so will make it impossible to mount the echo dot to the lid. (I learnt this the hard way!)
Since the horn itself is fairly well balanced, and the echo adds extra weight to the lid, I have found that it shouldn't be necessary to do anything else to attach the lid other than a friction fit. I suppose some magnets could be added but as long as you don't roundhouse kick this thing its not coming off by itself.
Now just place the lid with the Echo Dot in it on the base and you're done!
You can now put the lid on and tell alexa to play your favorite song!
After printing I rough-sanded all surfaces using 80 and 00 grit sandpaper, and applied copious amounts of Bondo to them. The rough-sanding helps knock down the highest points. as well as helps the Bondo adhere to the surfaces.
After the Bondo had have time to set up properly, it was nothing but sanding, elbow grease, primer and more sanding.
The primers I used was Rustoleum's high build filler primer, and their run of the mill gray primer.
Since the inside of the neck would be difficult to sand smooth due to the angles and lack of working space, I used XTC3D for smoothing out this part.
All in all, each part was given at least 1 coat of Bondo, spot putty and 3-4 coats of primer with wet sanding between each coat. Just expect a lot of sanding if you plan to achieve a smooth surface finish on this project.
The paints used was Rustoleum's ultra cover flat black and metallic copper. Both rattle cans.
How I Designed This
I modeled everything using Autodesk Fusion 360. I started by laying out sketches for all diameters of the horn. The first part I made was the widest part of the horn, simply called Horn.stl here on thingiverse. This was made using 3 sketches driving a loft. I then used the Shell function to hollow it out.
The neck was made in pretty much the same way, however the amount of sketches and angles to drive that loft function took some tinkering to get right. I am in no way an export in the use of Fusion 360, so after much trial and error I finally had a shape I was happy with.
The sketches driving the loft function for the neck.
The base was a similar story; More sketches and measurements.
It helps having a pair of calipers in front of you to help visualize certain dimensions while designing. Figuring out how much you want a part to stuck out, or how thick you want something, is much easier this way. And of course it's a must if you are designing something around a pre-existing object, in this case the Echo.
Some of the sketches that went into making the base.
Since the Echo have its speakers on the bottom, it lends itself very nicely to a project such as this. In fact, most pre-existing amplifiers for the echo Dot simply lift the Echo off the ground, so I decided to build further on this concept and made the chamber inside the base mimic this principle, in the simplest way possible.
Since I wanted to make this project with as little supports needed while printing as possible, I decided to just add a fillet to the bottom edges, and let the lid serve as the roof for the acoustic chamber. If I'm ever to do an update to this project, the chamber design is probably what I will work on, but so far, it works quite well as is!
An "x-ray" of how the Echo Dot sits in the chamber, exposing its speakers.
I hope you find this project as fun to make as I had designing, printing and painting it.
Its been in the works for some time now as a "nights and weekends" kind of project, and if you do make one, be sure to post your makes! I would love to see them!
Over and out!
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