I know there's one big reason you're reading this review, so I'll get right to it: The Google Home Max sounds just fantastic. It's a big speaker, powerful and dramatic. It's deep and weighty on the bottom, clear everywhere else, and well-rounded overall. It's voice is better than I expected, and also much louder. As much as I wanted to turn it up while I was testing it, I kept nervously nudging the volume down because it puts out such a wallop.
But the Google Home Max isn't a speaker I can rate solely based on the sound quality because it does so much more than just play music. It's a smart-home speaker with Google Assistant inside. Just like the Google Home and Google Home Mini before it, you can to talk to it, and it connects your voice commands to Google's myriad services and device ecosystems. Ask it to run web searches, tell it to adjust your Nest thermostat, request that it play a video on your Chromecast-ready television, or demand that it spool up your reggaeton Spotify playlist, and it delivers. These extra capabilities are what make it worth $400 (and yes, it is worth it, if you're a Google person). It's a party machine, sure. But it's also a voice-activated remote control for all of the available information and gadgets around you.
The visual design is quite boring, honestly; a gray blob covered in wool-like fabric. (Color choices are limited to a light gray or a darker charcoal so far.) The seemingly bland and uninspired look can be considered a feature, since it lets the speaker blend into any decor, which is likely the point.
The Home Max is roughly the same size as a Sonos Play:3, and just like that device, it works in two configurations. You can leave it laying down flat, where it delivers a stereo image from the four front-facing drivers, or you can tip it up vertically, where it runs in mono. If you buy two Maxes, you can tip them both up vertically and run them as a stereo pair. After they pair to each other wirelessly, you can place them on either side of a turntable or (cough) a CD player for something close to a traditional home stereo arrangement. There's a rubber base that sticks magnetically onto the body of the Max, so you can easily slap it onto whichever side of the speaker you want to place onto your table or shelf. It's a fun little touch.

