Music Speaker Set

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This DIY Music Speaker set is an intermediate electronics project that is perfect for practicing soldering skills and learning about electronics. Play music through your speakers, and watch the LED lights you wired in light up!

These instructions assume basic soldering skills, knowledge of how electricity works, and an ability to handle and work with electronic components. This is not a project for beginners due to the scale of the components and the number of steps involved. It must be supervised by an adult.

Head on over to the Learnary to find the Music Speaker Kit.
Tools & Materials
Material List

    Contents of Music Speaker Kit.

  • Mini-USB to 3.5mm/USB-A cable
  • Conductor cable (4x 24 AWG wires)
  • 2x 4Ω, 4W speakers

    • Small Bag 1

  • 1x Printed circuit board 1 (PCB 1)
  • 1x B103 10K Ω 3-Pin single linear dial wheel
  • 1x KA2284 5-Dot mono LED level meter driver
  • 2x 1 uF Ceramic capacitor (marked as 105)
  • 1x MD8002A Audio amplifier
  • 1x 25V 10uF Electrolytic capacitor
  • 1x 25V 470uF Electrolytic capacitor
  • 6x Blue LEDs 3mm (1 is spare)
  • 1x 1/4w 4.7k Ω Resistor - yellow - purple - black - brown - brown
  • 1x 1/4w 1k Ω Resistor - brown - black - black - brown - brown
  • 1x 1/4w 10k Ω Resistor - brown - black - black - red - brown
  • 2x Jumper wire (black and red)

    • Small Bag 2

  • 1x B503 50K Ω 5-Pin single linear dial wheel
  • 1x B103 10K Ω 3-Pin single linear dial wheel
  • 1x Printed circuit board 2 (PCB 2)
  • 1x KA2284 5-Dot mono LED level meter driver
  • 1x NS8002 Audio amplifier
  • 1x Mini-USB socket
  • 1x Switch
  • 2x 25V 10uF Electrolytic capacitor
  • 1x 25V 220uF Electrolytic capacitor
  • 5x 1/4w 1k Ω Resistor - brown - black - black - brown - brown
  • 1x 1/4w 10k Ω Resistor - brown - black - black - red - brown
  • 1x 1/4w 4.7k Ω Resistor - yellow - purple - black - brown - brown
  • 4x Jumper wire 2x black and 2x red
  • 6x Blue LEDs 3mm (1 is spare)
  • 2x 0.22 uF Ceramic capacitor (marked as 224)
  • 2x 1 uF Ceramic capacitor (marked as 105)

    • Speaker Container Bags 1 & 2

  • 6x Clear plastic speaker box components (slight differences between bags)
  • 4x M3x35mm Standoffs
  • 2x M3 Nuts
  • 10x M3x10mm Screws
  • Safety glasses (not pictured)
Tool list
  • Soldering iron
  • Solder (0.8mm recommended)
  • Wire cutters
  • Needle nose pliers
  • Tape
  • Solder wick or solder sucker
  • Third hand tool (optional)
  • Utility or craft knife
  • #1 Phillips screwdriver
  • Glue

    • Tips for managing many small parts:

  • Open bags only as you are ready to use them.
  • Lay the contents on a soft cloth or rubber mat, inside of a tray, to prevent them from rolling away.
  • Make sure all the expected contents are included before you begin to build.

    • Soldering Safety

  • Wear safety goggles and ensure good ventilation while soldering. Wash hands thoroughly with soap and water after handling solder. Solder contains lead.
Procedure

    It will take around 150 minutes to complete both speakers.

    Small Bag 1

  1. Open Small Bag 1. Take the PCB — the “front” is stencilled with information in white text. Turn it over to the back side and find “U1” and a stencil of the MD8002A audio amplifier with a notch at the top.
  2. Take the MD8002A audio amplifier out of its packaging and lay it on the “U1” position of the PCB. The imprinted black dot on the amplifier should be at the top, where the notch is on the stencil. A tiny dab of glue on the black part of the amplifier can be used to hold it in place.
  3. Solder the MD8002A audio amplifier in place. Start with a leg on either corner to stabilize the component, then go on to solder the rest of the legs. Make sure no solder spills over and bridges more than one leg. If you make a mistake, use solder sucker or wick to remove some of the solder and try again.
  4. Take the 4.7kΩ resistor (marked yellow, purple, black, brown, brown). Straighten its legs with needle-nose pliers, then bend them sharply 90 degrees at the point closest to the resistor. Put the legs through the front side of the PCB on either side of the “R1 4k7” stencil, then bend them flush against the back of the board to secure it in place. Solder the legs onto the board, then cut the legs flush on the back of the board.
  5. Take the 1kΩ resistor (marked brown, black, black, brown, brown) and repeat the process to install the resistor in the “R3 1k” position.
  6. Take the 10kΩ resistor (marked brown, black, black, red, brown) and repeat the process to install the resistor in the “R2 10k” position.
  7. Take one of the 1uF ceramic capacitors (marked “105”). Its legs are already bent down — install it the same way you would a resistor in the “C1 105” spot on the board.
  8. Take the last 1uF ceramic capacitor (marked “105”) and repeat the process to install the capacitor in the “C2 105” position.
  9. Take the B103 10k ohm 3-pin single linear dial wheel and place it in the “RP1” position on the board. These legs don’t need to be bent like the resistors or capacitors, but you’ll need to hold it in place while you solder it onto the back side of the board. A small piece of tape will work well.
  10. Take the KA2284 5-dot mono LED level meter driver and place it in the “U2” position on the board. The flat side should face up, towards the capacitors, and the bevelled side with writing on it should face down, towards the “D1” through “D5” stencils. As with the dial wheel, these legs don’t need to be bent before soldering. You may trim the legs once the chip is soldered.
  11. Take one of the smaller 25V 10uF electrolytic capacitors and place it in the “C4 10uF” position on the board. These components have a fixed polarity — the shorter leg with the white stripe on the component represents the negative side. Make sure that this negative leg goes into the pin with the white stripes on the board. As with resistors, bend the legs to secure it in place before soldering. Trim the legs once complete.
  12. Take the other 25V 10uF electrolytic capacitor and place it in the “C5 10uF” position on the board. Repeat the process from step 11 above to solder it into place.
  13. Take the 25V 470uF electrolytic capacitor and place it in the “C3 470uF” position on the board. Repeat the process from step 11 above to solder it into place.
  14. Take one of the blue 3mm LEDs. Without power they will appear clear. Like the electrolytic capacitors, LEDs have a fixed polarity. The longer leg represents the positive side, and the shorter leg represents the negative side. Unlike the capacitors, the markings on the board have a small hash on the positive side. Install the first LED into the “D1” position on the board, with the longer leg inserted into the hashed (right) side of the board.
  15. Repeat the process above for LEDs “D2” through “D5”. The sixth LED is a spare.
  16. Solder the two jumper wires to the centre of the board, in the box with “+” and “-” marked. Red goes to + (“power”) and black goes to - (“ground”). Strip the 24 AWG wires with a wire stripper, and “tin” the conductor by coating it in solder. Bend the jumper wire once it’s through the board just like the legs on a resistor. These jumpers are for the speaker.
  17. Put the PCB to the side. It is done for now.

    18. Small Bag 2

  18. Open Small Bag 2 and arrange the parts neatly to the side.
  19. The second PCB is very similar to the first. Install the MD8002A audio amplifier as in steps 2 and 3.
  20. Install the resistors as in steps 4–6. Note that there are 7 on this board — 5 1kΩ (marked brown, black, black, brown, brown), 1 10kΩ (marked brown, black, black, red, brown), and one 4.7kΩ (marked yellow, purple, black, brown, brown).
  21. Install the ceramic capacitors as in steps 7 and 8. Note that there are 4 on this board — 2 224s and 2 105s.
  22. Install the electrolytic capacitors as in steps 11–13.
  23. Install the blue 3mm LEDs as in steps 14 and 15.
  24. Install the KA2284 5-dot mono LED level meter driver as in step 10.
  25. Install the linear dial wheels as in step 9. Note that there are 2 on this board - 1 with 7 pins total, and one with 5. Match the pins to the board.
  26. Install the mini-USB socket on the “USB” part of the board. Don’t trim the legs of the component after soldering.
  27. Solder the speaker’s two jumper wires to the board as in step 16.
  28. Solder the two jumper wires for the power switch. They belong in the upper-right corner of the board, in the stencilled box with two hash marks. It doesn’t matter which wire goes in which hole.
  29. Take the 4-wire conductor cable. Use a utility knife to score the outer insulation 1⁄2” from one end. Bend the insulation back and forth along the score mark until broken, then pull the insulation off. Inside there are 4 24 AWG wires (red, blue, green, and yellow) and two strings.
  30. Cut the strings flush to the insulation. Using wire strippers, strip all four wires 1⁄4” and tin the exposed conductors. Solder the wires to the 4 pins on the top of the board — VCC, GND, D1, and D2. It doesn’t matter which wire goes to which pin, since we’ll build it to match when we install the other side of the cable.
  31. Put the PCB to the side. It is done for now.

    32. Speaker Container Bags

  32. Open either Speaker Container Bag. Remove the paper film protecting both sides of each piece.
  33. Follow the pictures provided to assemble the first speaker box — mount PCB 2 to its piece with 2 M3x10mm screws and their respective M3 nuts. Tighten them snugly, but do not overtighten the nuts — doing so may damage the board or components.
  34. Install the speaker cone assembly to the front of the box using 4 M3x10mm screws and 4 M3x35mm standoffs. The standoffs should be kept somewhat loose, as this will give you some room to work during final assembly.
  35. Solder the speaker jumper wires to the speaker: red to “+”, black to “-”. As before, tin the ends before soldering them to the lugs of the speaker.
  36. Route the 4-conductor cable through the small hole in the back of the box. Route the power switch jumper wires through the switch-sized opening in the side of the box. Install the micro USB cable and route it through the L- shaped opening in the top of the box.
  37. Finally, align the slots on each side of the box, and install the remaining 4 M3x10mm screws in the back of the box (a). Tighten each side evenly until all 8 screws are snug – but don’t tighten too much or you’ll crack the plastic (b).
  38. Open the second Speaker Container Bag. As before, remove all protective film prior to assembly.
  39. Begin by routing the 4-conductor wire through the small hole in the back of the second speaker box. Repeat step 29 to install the wires to the VCC, GND, D1, and D2 spots on PCB 1. Ensure the wire is routed through the speaker box before soldering.
  40. Solder the speaker jumper wires to the speaker as in step 35.
  41. Assemble the second speaker box as before.
  42. To test the speakers, plug the USB-A connector into a computer or USB power adapter. Plug the 3.5mm audio jack into a music device, and ensure the volume coming from the device is at maximum. The controller speaker has two dials — the one furthest from the speaker cone controls the volume of both speakers; the other controls the sensitivity of the LEDs to the volume coming out of each individual speaker. Adjust the volume to taste, and the sensitivity knobs to see the LEDs react to the music in real time.

    You’ve made yourself a set of speakers! This was a complicated project, with a lot of small parts. We hope you’ve enjoyed the process and learned lots about soldering along the way.
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