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DIY Bluetooth Speaker with Subwoofer (An Upcycle Project)

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by Ed

I have a not-very-frugal habit of shopping for technology. I am fully self-aware and I can often catch myself in a meta-I-Know-I-Don’t-Need-This-Crap-but-Want-to-Browse-Anyway moment. It hasn’t stopped me from shopping. (This is what often stops me from buying too often though.)

So this spring I was craving a newer, louder wireless speaker to listen to music at our country weekend place (our Mobile Home Makeover) and was about 30 seconds from pulling the trigger on a UE Boom 2 or Wonderboom.

But I didn’t. Instead, I wondered:

How can I make a homemade Bluetooth speaker? Can you turn wired speakers into Bluetooth?

And I dreamed up this upcycled idea: a DIY Bluetooth Speaker with Subwoofer!

I got a Bluetooth adapter in the winter, used, for about $20. It has worked really well at updating the soundbar in our DIY Hidden TV Cabinet into a wireless model to pair with our phones.

And it got me to thinking – what else could I Bluetooth myself?

While looking at my technology graveyard, in the part of the basement that Robin hates to go, I found an old computer speaker-subwoofer system and this is what I did with it. It makes a pretty cool/nerdy/fast build. So if you have a maker in your life, or you are one yourself, give it a shot.

So get out your old surround sound system – here’s how you can build your own unique new DIY Bluetooth speaker with subwoofer. A fun upcycled project!

how to make a bluetooth speaker with subwoofer

DIY Bluetooth Speaker with Subwoofer

diy bluetooth speaker parts

Here’s all the stuff for inside the speaker. I had all of it laying around, but even if you need to buy some parts, it shouldn’t cost you more than $30.

Materials to build a DIY Bluetooth Speaker with Subwoofer:

  • Bluetooth adapter (Like this one)
  • USB charger for Bluetooth adapter, if needed (similar to these)
  • Old powered speaker system with a line-in jack – it should still work/sound good (I’ve seen lots of these available at Re-Store and other second-hand places for less than $20)
  • Extension cord with 2 outlets
  • Plywood to build a box to hide all the ugly. (I used the same material as our basement wood panel ceiling and our herringbone ceiling.)
  • Wood Stain (I used Minwax in Early American.) and Tung Oil

Steps to Make a DIY Bluetooth Speaker with Subwoofer:

Step 1: Add Bluetooth to the speakers

Convert wired speakers to bluetooth
Test everything out before you squish it together and assemble.   
This is the extension cord, with the speaker system and Bluetooth adapter plugged in and the speaker line-in connected to the Bluetooth adapter. 
I then synced my phone and tested it to verify it wasn’t a pile of trash. Once you know it works, start building!
steps to Convert wired speakers to bluetooth homemade bluetooth speaker
This is my beta-concept.

All of this ugly will hide in an attractive box and pair wirelessly with my phone.

I’m showing it here so you can fully appreciate the amount of crap that will get hidden and give you an idea for what you might have to do with your own version.

Step 2: Modify the old speakers, as needed

homemade bluetooth speaker

Optional – I started by moving the feet from the bottom to the side of my sub-woofer, because the power switch was such that I needed to change the orientation so that it was accessible after I encased everything. 
You maybe won’t need to do this if your system has a different power button configuration.
diy portable bluetooth speaker
I wanted to plug all the components in the top, but still have the power cable come out the bottom, so I drilled a hole through the subwoofer new-top/ new bottom (Old sides) to allow the extension cord to pass through.

Step 3: Attach Bluetooth to the Subwoofer bottom

how to Convert wired speakers to bluetooth

I attached the legs to the new-bottom and fed the extension cord through. 
I also positioned the Bluetooth adapter on the bottom so it would always be accessible to sync in the future. 
I plugged it all in and carefully stapled the wires in place.

Step 4: Attach wires and speakers to subwoofer

convert old stereo to bluetooth
Back on the top of the speaker assembly, I checked all the connections and carefully drilled and screwed down the smaller speakers where I need them to stay. 
The wire-spaghetti was coiled as neatly as I could make it coil (i.e. not very neat).
build bluetooth speaker
Another view of the ‘guts’. This time it is all connected, secured and ready to hide. 
It is worth testing again just to verify all your cables are plugged in correctly. It is soon going to be hard/impossible to access some pieces.

Step 5: Make the DIY Wooden Bluetooth Speaker Box Face


On to the pretty stuff. Choose a hole pattern for your speaker grill. I choose a small-to-big dot pattern, but anything with enough space for sound transference will be fine. 
Line it up on your face-panel and flag the centre of each dot for drilling. 
Alternatively, find a fabric you can use to cover everything sound needs to pass through. 
This is my dot matrix (Wha-what? old tymey printer nerd joke!).

It sucked making it. But the reward is a cool, custom speaker face.
Now for more tediousness! Starting with a larger bit, begin drilling out the holes.

I had access to a drill press, but I still did some after with a hand drill and that is possible too. 
Every couple of rows, swap out a smaller bit and make the pattern reduce down.
Finished speaker face. 
Don’t be rushed like me. take time to sand everything and remove all the little hole spurs. I did a less-than-thorough job and had to re-sand sections after the whole unit was assembled. Not easy.

Step 6: Assemble the Speaker Box

homemade bluetooth speaker
Measure and cut the sides.

Check them in place by hand to make sure everything is going to fit.
how to build a bluetooth speaker
Attach sides.  
I used a piece of plywood to leave a small gap at the bottom. 
My subwoofer box was thick and had lots of space inside so I didn’t need to worry too much about nailing into it. Check yours before your nail. 
Or better yet, use glue and clamps for a nail-hole-free look.
how to build bluetooth speaker
Here is the back of my box – you can see why I needed to re-orient the legs. 
The hole on the back is to make the power switch accessible.

I also ended up drilling two additional ‘carrying finger holes’ near the top (not pictured yet). It totally would’ve been easier to drill at this stage… Again, learn from me.

I cut a chunk of scrap pine panel (we love using it on stuff) and cut it slightly smaller to fit inside.

This gave the box a solid top to nail into and I could just glue the final piece of panel to it for a cleaner finish.
This is the aforementioned top panel being glued on.

(Yes, that’s Friday night darkness coming in the workshop window, so what? I suppose you’re hanging out with friends or family on your Friday night and not building awesome nerd projects.)
make your own bluetooth speaker
Another shot of the almost finished bottom to give you an idea of how accessible the Bluetooth sync is.

I also made the back panel with slightly more of a gap than the front and sides in order to accommodate the extension cord.
bluetooth speaker with subwoofer


Well, almost done. I stained and sealed the unit with a dark stain finish and Tung Oil.

I suggest a toothbrush or some other small brush to use for staining the grill holes. 
diy bluetooth speaker wood box

You can find lots more ideas to save money on technology here!

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Tuesday 22nd of September 2020

amazing. this really helped me


Monday 28th of September 2020

Glad to hear it, Wale! :)


Tuesday 11th of June 2019

Sheesh, wish I could hear it! Very interesting, you are the very best nerd, keep up the good work!