No fix? No problem. Let's instead proceed with the dissection and see what else is inside these dead-battery wireless earbuds.
If you’ve already read one of last month’s posts, you know that my engineering colleague Huan Nguyen wasn’t able to resurrect my prematurely deceased set of Beats Powerbeats Pro earbuds. Once again following my long-time mantra “When life gives you lemons, make lemonade,” however, I’ve decided to go ahead and do a full teardown of one of them, since Nguyen’s abundant still and video image set that he took during “surgery” and subsequently shared with me (and I subsequently shared with all of you) only got as far inside them as the battery. I won’t be retracing his already-documented steps, so make sure you check out Nguyen’s already published written and photographed play-by-play before proceeding.
Here again are Apple’s “stock” images of the earbuds standalone (same color as mine):
and with one of them placed in the charging case (the white-color variant):
The charging case still works fine, so I’m keeping it intact as a spare for the replacement Powerbeats Pro set that I’ve bought (fool me once, shame on you; fool me twice, shame on me?). I’ll be re-incising and further disassembling the right earbud, which Nguyen had originally cut into with an ultrasonic blade. To be precise, however, my cutting won’t be from scratch, as at my request he left the cover detached on this earbud to make my job easier:
Here’s the cover standalone, front side first, showing the function-activation button:
And now the back side, revealing the button “spring”:
The switch activated by the button, located atop the battery cover, is now obvious:
Also, correct me if I’m wrong, readers, but I’m pretty sure that’s the MEMS microphone to the left of the battery cover, at the top of the assemblage. Recall that this particular earbuds model, whose introduction dates from early 2019, doesn’t implement ANC, only PNR, so there’s no need for multiple per-ear mics. That said, there are two vents feeding the mic with sounds from the outside, which I’ll show you shortly.
Let’s get that black plastic piece at left off:
Truth be told, I don’t know exactly what the purpose of this piece is. It’s not metallic, so it can’t provide any electrical shielding capabilities, nor can it act as a heatsink for the H1 SoC (the successor to Apple’s initial W1 chip for wireless headphones) underneath. It may simply provide added structural integrity and protection from impact, moisture, etc. damage to the circuitry underneath. Note too, that I never found a Bluetooth antenna, either discrete or embedded in the PCB (nor did iFixit, as far as I can tell), so perhaps it’s integrated within this piece, too.
Time to pry the PCB out:
Turns out it’s a multi-PCB “sandwich”:
From this vantage point, you can see the “prongs” that mate with the charging contacts on the earbuds’ lower edge:
And this perspective shows you the switches corresponding to the two-button control toggle along the earbuds’ top edge:
Now look more closely at both external-view shots and you’ll see a small hole next to both the charging contacts and the two-button toggle. Those are the two vents that feed the microphone, which I mentioned earlier. And if you look really closely, you can see the interior mesh associated with one of the external holes, designed to keep dust and other particulates from getting inside. I’ll show additional images of the holes and their mesh mates later.
Let’s get that “sandwich” fully unfolded:
One of the frustrating aspects of tearing down Apple products is that many of the ICs don’t have top-side marks at all, and for the ones that do, they’re Apple-proprietary stampings that don’t give a clue as to what’s inside the package. The earlier-mentioned H1 SoC (succeeded by the more recent H2) is obvious in spite of its attempted anonymity. And I might presume that the IC nearby the charging “prongs” manages the earbuds’ power and battery-refresh functions. But other than that……
And here’s what’s left after the PCB “sandwich” was extracted:
You can see that I severed a ribbon cable routing into the earbud during this part of the procedure. We already know that there’s a speaker down there, as well as an IR sensor that detects if the earbud is actually inserted in the ear (pausing playback when the earbuds are removed, for example):
so I suspect we’ll find not only a transducer, but more chips. First off though, what’s with that piece of metal at left, underneath the now-extracted PCB?
It’s actually two pieces of metal, the lower one a quite-strong magnet. It took me a minute to realize its primary purpose; that’s how the earbuds “grip” the charging case when inserted in it (plus it adds structural rigidity, of course):
To get at whatever’s inside the earbud, I tag-teamed a box cutter and a thin flat head screwdriver acting as a chisel:
There are actually two more mini-PCBs, connected together by another ribbon cable, with another ribbon cable heading out of the second mini-PCB (the one glued to the back side of the speaker) and even deeper into the earbud:
After snipping the first ribbon cable to get the two mini-PCBs apart, I used the flat head screwdriver to dive further into the earbud structure:
Inside, unsurprisingly, was the dynamic transducer with the IR sensor underneath that:
But one other goodie still awaited me. See the mesh in the first shot that follows?
Hold that thought for a minute. Let’s now turn to the other mini-PCB, both sides of which you’ve already seen (albeit somewhat obscured) in previous chronologically-ordered images:
With it removed, here’s what’s left:
What’s that in the second shot…more mesh? Yes! At first, when I encountered it, I wondered whether there might be (previous no-ANC comments aside) another mic deeply embedded in the earbud. But that didn’t make sense, because the only thing it could “hear” would be what was coming out of the speaker. Then I realized that what I was actually looking at was a bass reflex port for enhanced low frequency reproduction, which conveniently does double duty in reducing ear pressure for better long-listening-session comfort. Apple/Beats’ marketeers’ referring to it as a “micro-laser barometric venting hole” is a bit hyperbolic, but still, slick!
Speaking of microphones, I’ll close with, as previously promised, a more focused look at both vent holes and their (micro-laser?) mesh associates:
And with that, it’s over to you all for your thoughts in the comments!
This article was originally published on EDN.
Brian Dipert is the Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.
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