REM

It lives in your home. It's always listening. It's the Amazon Echo, a voice-controlled smart speaker, and it's the closest device yet to the computer in Star Trek. The Echo's auditory assistant, called Alexa, seems more responsive than Siri—and it's about on par with recent Apple fare on the repair front, too. But the Echo's tricky construction makes disassembly a tad difficult without a manual, so the Amazon Echo earned itself a reasonable 7 out of 10 for repair. Teardown Highlights:

• At 9.75" x 3.27", the Amazon Echo stands just a bit bigger than a couple cans of soup.

• Amazon sealed the Echo up tight, with nary a fastener in sight. But peeling up the foot reveals four impressively long T10 screws holding the bottom stage of the Echo rocket in place.

• The heavy duty woofer has an even heftier magnet than its tweeting twin. Amazon promises "deep bass response," thanks to this woofer and some funneling by the reflex port. The reflex port boosts the bass while minimizing distortion. Its strange shape takes full advantage of the limited space inside the Echo while allowing Alexa to yell at you from across the room.

• Now for the fun part! The volume dial contains the user-interactive bits: The top portion spins freely, using a greased-up gear to turn an encoder. The Echo uses a gearing system and encoder to track motion of the outer wheel, whereas the Nest Thermostat uses an optical sensor to watch the outer ring spin by.

• Around the edge of the wheel, we find the microphones responsible for hearing your commands (six on the perimeter, plus one in the center of the board), and LEDs used to indicate Alexa's acknowledgement.

  • Chips on the Echo boards: • Texas Instruments DM3725CUS100 Digital Media Processor • Samsung K4X2G323PD-8GD8 256 MB LPDDR1 RAM • Texas Instruments TPA3110D2 15W Filter-Free Class D Stereo Amplifier • Texas Instruments TPS53312 • Texas Instruments TLV320DAC3203 • SanDisk SDIN7DP2-4G 4 GB iNAND Ultra Flash Memory • Qualcomm Atheros QCA6234X-AM2D Wi-Fi and Bluetooth Module • Texas Instruments TPS65910A1 Integrated Power Management IC • Texas Instruments LP55231 Programmable 9-Output LED Driver • Texas Instruments TLV320ADC3101 92dB SNR Low-Power Stereo ADC • Texas Instruments SN74LVC74A Dual Positive-Edge-Triggered D-Type Flip-Flops • S1053 0090 V6 Microphone