20W 2.1 Bluetooth Speaker

I created this bluetooth speaker as fun project. I wanted to do it for a long time so i started out by reading other instructables and thinking of a design. I loved a look with a leather finish and wanted to make my own version.

I loved building this speaker so i hope you do too and that my first instructable is usefull!

Design

The fullrange speakers have their own small cabinet so they won't influence the bass reflex. I did use a bass reflex pipe. Visaton has stated the cabinet volumes and the respective bass reflex pipe diameter and length for the best results. I used these values to get a volume around 10L with a 6.8cm bass reflex. You can look up the specs at the Visaton site with the woofer. I used 12mm MDF and a copper plate to use in the top hole where the volume/bass potentiometers and power switch will be. The voltmeter and micro usb charging port will be at the back panel. In front of the speakers there will be a frame with a speaker cloth around it. It is a personal choice if you want to see the speakers or not.

Components

The following components are needed to build this speaker:

• Visaton W 100 S 4 ohm woofer
• 2x Visaton fr7 4 ohm
• bassreflex tube visaton 6.8
• on/off toggle switch
• Aux chassis part
• usb bluetooth audio module
• 4x 18650 batteries (Make sure you don't buy unsafe fake ones!!)
• battery holder
• battery protection board
• voltmeter
• Small on/off switches
• artificial leather
• speaker cloth (i just used a linen cloth)
• copper plate (or brass for example)
• MDF 12mm

I jused a 120x60 cm MDF sheet and cut all the panels with a jigsaw. There were no screws used in connection the pieces, just wood glue. When you glue make sure you have enough clamps to hold everything together with some force. As you can see on the last picture my jigsaw skills are not that great so i needed to seal up the small gaps between plates with some kit. The holes were made by drilling a hole and putting the jigsaw in. It is pretty easy to make curves with a jigsaw in MDF

I covered the cabinet with a piece of fake leather and glued it with a contact cement (Bison Tix). It gives a great look to the speaker. I just watched some youtube tutorials on how to glue artificial leather. It is not easy to make the corners look great and the top hole for the controlnpanel was even harder. Some leathers are easier to handle and stretch when heated up with a hairdryer to wrap it in a hole. Make sure to paint the mdf underneath cornersnor difficult parts in case some mdf shines through.

I coated the copper plate with a transparrent spay lac. Copper will get a lot of stains from your fingers if you don't spray it.

Wire and solder the components as displayed in the image. The bluetooth module has to be opened in order to solder the power wires. The battery's are parallel and therefore a step up converter from 3.7 to 5V is used. The bluetooth module is wired with a 3.5mm jack cable to the jack input of the amlifier ( different from the image). This is because i also added an aux input and used the 3 pin audio input on the amplifier for it.

The final result is shown in the pictures with the front and back. The micro usb input on the back is for charging. The batteries last very long. I did not do a test on how long but i can assure that when listening a few hours a day the batteries will last at least two weeks if not more. This depends on the capacity and quality of your batteries but also the volume you set your music to. Some changes were made during the process with respect to the original design.

Bluetooth module

The bluetooth module i just was very bad and caused a lot of distortion of the sound. This was awful to listen to so i drilled a hole in the control panel and added an aux port for connecting with a cable. This was the bad noise was gone. I do know that it is no longer a bluetooth speaker but this will be added again in the future. There are also bluetooth audio modules on batteries which have an aux output. This would make things easier.

Front cover

I did not have enough wood left to create the front cover which will be made in the future and gives a different look to it. It will be easy to take it off again because i also like the look with the speakers being out in the open.

Treble control

The treble control which is in the wiring schematic is not implemented. This is because it was not really nice to do and the potmeters I had were of too high resistance for this application. I would recommend to use an amplifier which already has bass, treble and volume controls on it to make your life easier.

Final remarks

After a while the amplifier's right speaker output died so i can only hear the left side. However if i would do this project again ( or just improve this one) I would recommend a different amplifier which already has a treble, bass and volume control and maybe a 12V amplifier to get even more volume for use in case of a parties.

I hope you liked my project and hopefully my first real instructable was useful to you. Good luck with your project! If you have any questions feel free to ask!