Teardown: Amazon’s Echo Plus

Amazon was the first company to popularize the smart speaker concept. The Seattle giant’s first foray into speakers has been shockingly successful (selling tens of millions of units to date). While the revenue generated by Echo is a tiny fraction of Amazon’s top line, every detail about the implementation of the product signals a company spearheading a new product category and a business model that doesn’t depend on profitably selling consumer electronics hardware.

This is clearly an extremely unusual way to design a speaker.

🎵Upside down, boy you turn me, inside out, and round and round.

From the very first part I looked at, it became clear Amazon did not design Echo like a traditional speaker. The entire product is assembled like a tubular plastic sandwich with all components connected vertically around a central axis (us engineers call this a stack-up). It’s an extremely unusual way to design a speaker.

🎵Every now and then I fall apart

After peeling off the first plastic part in the stack-up, we see the audio and Bluetooth board. The bottom of this board handles the digital circuitry for generating and manipulating the audio signal, while the top is the amplifier, power input connector, audio out connector, and EFR32MG12 Bluetooth chipset (EFR32MG12P232F1024GM48 — say that three times fast). The EFR32MG12 has a configurable sub-GHz radio programmed for the Zigbee home network protocol, which is one of several future low-power, IoT home networking standards. This is yet another clue that Amazon is thinking about Echo as a gateway to the home rather than a speaker with some new tricks.

🎵A little bit louder, now

Peeling off the next layer in the stack-up, we see the tweeter which plays the high-frequency spectrum. Both the tweeter and midrange drivers are downward firing, which again is quite rare for consumer electronics speakers but a near necessity for the cylindrical design. A few interesting notes about this bottom speaker “reflector” part to the right in the above photos:

  • This part is extremely complex for such a simple functional part. There are a surprising number of ribs, undercuts, and bizarre geometry not often found in consumer electronics parts.
  • The external surface has no draft (meaning the wall has no angle). Draft is a required feature of nearly every injection molded part so this part is actually two parts (the inner/upper part is injection molded and the outer surface is extruded or machined). Again a very unusual decision that is both beautiful and expensive.
  • This conical reflector + outer surface part is easily 3–5x more expensive than I would have guessed from the outset.
🎵Black hole sun, won’t you come…

Pulling off the sleek speaker grille, there’s a shocking secret here: this is an extruded plastic tube with a secondary rotational drilling operation. In my many years of tearing apart consumer electronics products, I’ve never seen a high-volume plastic part with this kind of process. After some quick math on the production timelines, my guess is there’s a multi-headed drill and a rotational axis to create all those holes. CNC drilling each hole individually would take an extremely long time. If anyone has more insight into how a part like this is made, I’d love to see it! Bottom line: this is another surprisingly expensive part.

🎵I’m only happy when it rains / I’m only happy when it’s complicated

Next in the stack: the tweeter ‘carrier’. Not a ton to see here, other than another surprisingly complex part. As one of my old mechanical engineering professors always said “plastic is free” so this relatively standard part likely doesn’t add much cost even though it looks bizarre.

🎵Life in plastic, it’s fantastic

As successive layers of the stack are removed, it’s starting to become painfully clear that Amazon is spending far more to produce this speaker than I initially guessed. This primary structural part (where the main circuit board is mounted and that holds the mid-range driver) is again, wildly complex. Looking at the draft angle (blue arrow and dotted lines) we know this part is pulled out of the injection mold tool vertically, which is both expensive and fraught with design constraints. Why Amazon decided to mold the part this way is beyond me. It also strikes me as unusual to place the heavier driver (the midrange) above the tweeter. Usually speakers are designed with the heaviest magnets as close to the bottom of the product as possible for stability.

The main PCB sits at the center of the product and is loaded with Mediatek parts (moving away from TI in the first generation Echo product line). A few of the major chipsets:

  • Mediatek MT8163V is the primary microcomputer/processor, similar to one you’d find in a tablet PC. It’s a shockingly sophisticated 1.5GHz quad-core processor with built-in graphics, DDR3 memory, WiFi, Bluetooth, camera capability, GPS, FM radio, etc. Interestingly, this is the same system-on-a-chip used in the 6th generation Amazon Fire HD; maybe Amazon had a few extra laying around? (Sorry, Bezos…)
  • Mediatek MT6323LGA power management chipset
  • Cypress/Broadcom CYW43569PKFFBG 5G WiFi radio with Bluetooth (yes, a second bluetooth radio)
  • SK Hynx H9TQ64A8GTAC DDR3 Flash memory
🎵You are so beautiful, to me, can’t you see?

And finally the last layer of the stack (and the top of the product) we have the volume control, two pushbuttons, and microphone array/user-interface PCB. The volume control is an incredibly creative assembly built around a continuous rotation potentiometer, an elegant round light pipe and custom gearing in the volume ring. It is nothing particularly expensive or complex, but it’s a very neat design.

Pulling the user-interface assembly completely apart, we see how many parts it takes to build a custom volume control. Again, Amazon is willing to spend real money to build something interesting and differentiated. There are eight custom-molded parts that come together for the volume knob, a very different story than the single part and capacitive sensors for the Sonos One.

On the microphone PCB, we find seven microphones (one more than the Sonos, the extra being in the center of the board likely for directionality) and 12 LEDs that display the volume and directionality of Alexa’s voice. I’ve always loved the light display on the Echo line of products but I’m curious why the LEDs aren’t equally spaced (maybe to show directionality around the mics?)

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