Building a Bluetooth speaker is easy with the availability of cheap Bluetooth receivers, but surprisingly there isn’t a simple way to build a pair of truly wireless stereo speakers. [Matt] from DIY Perks realized that modern Bluetooth earbuds contain all the electronics to do just that.
Due to the popularity of these earbuds, a broken pair can be picked up very cheaply on eBay. Usually, it’s only the battery or speaker unit that give out, neither of which are required for this build. [Matt] goes through the process of taking a pair of earbuds apart, and then soldering on battery and speaker wires. The speaker wires are connected to an audio amp, which drives a mid-range and treble speaker driver, and a subwoofer. The outputs to the amp are also filtered to match the speakers. Power is provided by a set of four 18650 cells.
[Matt] housed the driver and electronics in some attractive CNC machined wood enclosures. In the video, he places a lot of emphasis on properly sealing all the gaps to get the best possible audio quality. As with all of his projects, the end result looks and performs like a high-end commercial product. We’re almost surprised that he didn’t add any brass to the speakers, as he did on his USB-C monitor or PS5 enclosure build.
Mark? I thought it was Matt…
Anyway, I have a project going to take some Bluetooth earbuds and make them into a receiver with a 3.5mm jack. All parts are currently acquired except an enclosure, which will be difficult due to the fact that I have neither CNC router nor 3D printer.
Check if there’s a library or other public venue that has a 3D printer you can use, or look for a maker space nearby. When I got my covid shot, I saw there were a couple of 3D printers in the hospital’s health sciences library.
Non-square boxes are cool and all, but you could totally make these out of whatever you’ve got on hand. I’ve been known to prototype speaker enclosures out of cardboard (gasp!) before pulling out the saw.
Most commercial speakers are made out of cardboard – well, low density fiber board, which is practically the same. With that in mind, you could very well laminate a speaker enclosure out of watered down PVA glue and some copier paper.
Look in the recycling bin or hit the local hardware store for PVC pipe or electric fittings in plastic. Stroll down the housewares isle at the thrift store. Best idea, make or get a patch cord for better sound. I’d rather plug in to make it work than plug it in to have to charge it and hope it keeps working long enough unplugged.
Blurtooth what? It’s a whole family of growing standards from robot speech quality to high definition sound. If it don’t spec in details it’s the outdated stuff. You need to be up to date at both T and R ends. Spend some time reading the Wikipedia article and charts.
Lastly by definition there is no subwoofer without a woofer present. Most 3/4+3/4.1 sound setups have just one woofer and no subwoofer.
There’s various versions of the Blackberry Audio Gateway. I have one that takes mini USB for power and has a 3.5mm stereo output jack. The top surface is touch sensitive.
Read the first sentence if the article.
What a classic idea! Why didn’t I think of it first?
…goes off to tear open his wireless earbuds…
Why faff around on ebay when perfectly working ones can be had for ~$15 from Amazon?
Wax free too.
A BMS and a charging port would be nice improvements to the little speakers. Thought initially that a regulator would be better than running the headphones off 1 cell, but the current draw would be so low the BMS would counter it every time it’s charged.
His circuit for tuning the sound from the earbud output to the input of the amp looks interesting. I’ve got a set of these:
https://www.minidsp.com/products/acoustic-measurement/ears-headphone-jig
And the calibration curves for monitoring distant sound sources, over ear headphones and earbuds are really different.
Side-tracked by rambling – back to point…
Yuck, used earbuds!
Because “Reduce. Reuse. Recycle”!
Why create more e-waste?
I’m stoked that people are focusing on the overall positives of this build rather than obsessing about the electrolytic capacitors that he used in the crossovers. You are all better people than I am.
Polypropylene, for the love of all that’s holy! (Only half ironically.)
But 100% seriously, getting good stereo separation in addition to portability by using a pair of earbuds is _super_ clever. And these were beautifully executed.
For a DIY build, it is clever, but these things are out there as a product, for far cheaper than a pair of (new) wireless earbuds. For example the Creative T15. If you simply want to jazz things up with a nicer box, I would start there, because it has all the electronics already.
Argh,…
Those are completely wireless aka battery powered, the Creative T15 are NOT.
His project wasn’t just about receiving audio over bluetooth or about a “nicer box”.
BTW look at the drivers he’s using, they are pro-grade.
“pro-grade” doesn’t mean anything if you stick them in a random box and feed them with a random sound source with an unknown frequency response.
And adding batteries instead of the wall adapter would be trivial.
and they’re not independent, they’re wired together.
I thought nonpolarized electrolytes were a’ight for crossovers? Are there low-voltage (sub-63V) polypropylene caps for audio? I’ve mostly used the 400V-rated ones, and they’d be needlessly chunky for an audio signal.
i came to the comments to try to better understand the crossovers he built. he appears to be using carbon filament resistors in the place of inductors? and the curious thing he did with paralleling the capacitors(why not just use a larger size single capacitor?
obviously they work in some capacity, but i haven’t come across the technique or it’s operating principles anywhere.
Thats a really neat idea! The only thing I’d be worried about (which he doesn’t seem to have an issue with by the sounds of it) is strange EQs in certain drivers, but I’d guess you’d almost be more likely not to have this issue with the really cheap sets with low R&D (as opposed to your bose / parrot / jaybirds where the presumably EQ it up the wazoo to make it sound good on imperfect drivers).
I think the Bose speaker sounded better – much clearer without a muddy mumbling bass that covers everything.
But that’s just the futility of comparing speakers via a youtube video. Some people even do “digital vs vinyl” on youtube, which is hilarious.
Don’t get me started on some reviewers comparing the sound improvements/difference of wires on YouTube.
A bit off-topic maybe, but I wonder how these earbuds work from the Bluetooth perspective. They are visible as a single BT peripheral. Does this mean that one of these is a “master” receiving data from the source and forwarding a half to the other earbud? Or do they do some magic by which they emulate a single device while working their radios in coordination?
Usually one speaker syncs with the device that seems the audio then using Bluetooth again, synced to the other speaker, it splits and sends the other channel to the other speaker but waits a bit before playing to account for delay between transmission. It’s basically a Bluetooth daisy chain.