Introduction: HiFi Music Box With Bluetooth

About: Studied journalism, engineering and philosophy of technology; co-founded the FabLab Cottbus e.V.; works at the Open Knowledge Foundation Germany e.V.

There are a few bluetooth music boxes on the "market", but a lot of them have a problem: They sound bad and/or are not easy to build. This instructable is about an easy to build version (the electronics are ready to use), with a good hifi sound. Because of the reflex system, the box has also a lot of bass.

The case is adjusted for the Tang Band speaker. If you want to use a different one, you need to draw a new case (and maybe also different reflex tubes).

What you need:

  • 2 Speaker driver (Tang Band W4-655) - example
  • 1 Digital amplifire with bluetooth TDA7492P (50Wx2) - example
  • 2 MONACOR bass reflex tube BR-45 TR
  • 1 Power switch - example
  • 1 Power plug - example
  • 1 DC-DC XL6009 adjustable step-up (input: 3V- 32V output: 5V- 35V) - example
  • 1 Power bank
  • Wood for the case (1m * 1m * 5mm thick medium-density fibreboard)
  • Some cables, screws, wood glue

Costs: ± 110€

Tools: Laser cutter, drilling machine, soldering iron

Step 1: The Case

For the case you need a laser cutter. Just laser it out. BUT: You may need to colour the lines for your system. Look at the hints in the screenshot for more information!

After you lasered the case, you need to drill the holes for attaching the speakers, the power plug and switch (and analog audio input, if you want). The holes are not part of the drawing, because of the differences between the possible parts.

Place the bass reflex tubes at the end. You may need to sand the holes to do that. And glue the case together, but keep one side open (this is the service opening). To close this later and prevent noises, glue 3 small wooden parts at the inner side of the case (look at the picture in the next step).

If you want to build your own box, use this tool.

Step 2: Put Everything Together

Adjust the DC-DC converter (use a screwdriver for that). The converter needs to have an output voltage of ± 12V. After that, put everything together (like in the drawing). I attached the power bank to the back of the speaker. The place depends on the size of your power bank.

Check the right connection of your speakers! Booth speakers need to be connected the same, otherwise you will have interferences and a bad sound.

For better tone, put a bit of wool on the ground (I used some out of an old pillow) and remove the buttons on the amplifire board (they create noises).

Have fun!