SANDBOX 2.3 HiFi Speaker by latunen

Last crawled date: 3 years, 1 month ago

I wanted to make a nice looking HiFi grade speaker that would cost under 100 euros including all parts and needed only 1 kg PLA to print. Of course with only 1 kg plastic the speaker cabinet would be way too light to work well. The best solution was to make the cabinet walls hollow and fill it with sand. I made several different prototypes and this SANDBOX 2.3 works best for several types of elements and reflex tube lengths. The full range element makes this speaker easy to assembly and no soldering is needed.
The 2 kg sand inside the SANDBOX 2.3 speaker walls dampens vibrations and the total mass of almost 5 kg makes this speaker sound really clear and precise without loosing bass experience. This is also evident in the SPL curve which is flat and reaches really low for a 4 inch element. It is a good idea to combine HexiBox subwoofer with the SANDBOX 2.3 speaker to get extra punch for the bass. This setup can perform big sound even with a small and cheap bluetooth amplifier like the FosiAudio BT30D to which also the HexiBox is easy to connect directly.
The element I used and works great in SANDBOX 2.3 is TANG BAND W4-1320SIF 4" Bamboo Full Range Speaker. This element can be found in several online shops, I bought mine from www.soundimports.eu. I also bought the damping material there. The sand I bought from an aquarium shop and the connections, cable, screws and even damping material can be found in hardware/car part stores. The speaker cable connectors I ordered from AliExpress China where you can get them really cheap.
The best amount of the damping material is 75 - 100 grams. Printing settings I used 4 perimeters, 4 solid layers and 20% gyroid infill. It is important too use high bed temperature (60-70C) and wide brim to prevent warping. The seam I places so that it is in the bottom of the speaker. Because the body and backside parts are big the cooling fan can be set as low as 70% for better result. Only small amount of support material is needed.
If you have another type of elements then you can modify this SANDBOX design to fit your element in the face of the cabinet. You also need to calculate the length of the reflex tube which can be done easily here:
http://www.mh-audio.nl/Calculators/WVC.html
For the reflex tube length calculation you can find the needed "tuning frequency" in your element specs sheet. The inside volume of the SANDBOX 2.3 speaker is 3,85 litres but in calculation you have to minus the volume of the tube and the element. I used volume 3,6 litres and frequency 75 Hz in my calculation.
I have added several pictures of the making of the SANDBOX 2.3 speaker to get the idea how easy it is to put together just with a screwdriver and pliers. Before you start to fill the cabinet with sand remember to cover the screw holes! When you fill the cabinet knock the cabinet all the time to get the sand tighten. And after you have placed the backside part in place and secured it with screws then add more sand from the hole. You have to apply sand to the hole almost 20 times before the walls are really full. The tap to cover the hole might be tight so you can sand it or print it 1-2% smaller. If you find the outer edges of the speaker to be sharp you can use a knife or sanding paper to make them rounder.