That environmental data is used to determine which parts of a song should be routed through which speaker inside the HomePod, a process that helps build a surprisingly spacious soundstage. A singer's vocals, for example, are likely to be blasted right at you while an underlying piano melody is concentrated around the sides to give it a more ambient feel. The level of complexity at play here is downright wild for a speaker of this size.
Over the past few days, I've asked the HomePod to play an eclectic mix of music, and with very few exceptions, every track I tried sounded bright and balanced. And, thanks to the HomePod's omnidirectional design, you can walk around it without noticing any massive differences in sound.
One of the most notable things about the HomePod is the excellent job it does highlighting the myriad moving parts of a song. The main brass melody in "Tank!" (of Cowboy Bebop fame) gets the star treatment for most of the song, but elements like the ever-present bongo and shaker never get lost in the mix. On previous listens through different speakers and headphones, it was easy to forget that they're there, but the HomePod did a great job balancing those bits and letting them shine. It's not going to be as immersive as a pair of high-end bookshelf speakers, but if you close your eyes, the leap isn't a huge one.
In general, you can expect the HomePod to emphasize vocals and mids, and that's usually a great thing. Brian May's guitar solo and Freddie Mercury's growl in "Somebody to Love" felt punchy and present, while the piano and drums provided a solid foundation for the mids and highs to dance on. In Kesha's "Praying," her voice does most of the heavy lifting, but the HomePod's excellent clarity revealed the tremolo in her words during the relatively bare first half. The effect isn't always perfect, though: In They Might Be Giants' "Ana Ng," John Linnell's nasal croon seemed to rise above the rest of the mix, overshadowing the rest of the instruments.