Bookshelf Speaker Box that can be filled with sand 3D print model
3D printing makes it easy to make all kind of amazing shapes for Horn designs. The downside is that plastics do not perform very well on the acoustic side. One issue is that the walls will resonate in a disharmonious way. To solve that particular problem this Speaker Box has hollow walls that can be filled with sand. This makes it very heavy (1775 gram) for its size. The vibrations in the walls of the box will be canceled out much quicker now.
The assembly of this Box is very easy. First print out the parts. Glue “ inside L.stl” & “inside R.stl” together. Then glue them into “outside L.stl”. As last close the Box by gluing “outside R.stl” on.
Then the box can be filled with sand. On the Photo you can see that mine came from the garden. Note that finer sand is better. Also the dryer the better. With a Funnel it's easier to get the sand in. After the sand is in it can be topped off with the “sand lids” (.stl). Putting on these Lids and than shaking the box helps to get the sand in all the corner and crannies.
After that the Speaker can be installed. The Wire runs trough the inside tube. Hot glue is used in this example to make it airtight.
At 100% size the dimensions of the Box are 170 x 120 x 100 mm. The Bore for the Speaker has a diameter of 60 mm. The mounting holes for the screws are 50 mm apart from each other. The depth of the Speaker chamber is about 77 mm. Of course the Box is scalable to let it fit a Speaker with different installation size. At a resize of 110% the bore for the Speaker is 66 mm. 120% =72 mm, 130%=78mm,140%=84mm, 150%=90mm, etc.
This model is tested on a FDM Printer with an resolution of 0,2mm and a Nozzle of 0.4mm.
With the settings : 3 Wall layers, 4 Top & Bottom Layers, Infill 20% and a Skirt of 2 lines it takes around 52 hours and 492 gram of material.
If you have any questions, feel free to ask :-)