iOS 11.4 is available today, and it comes with two notable new features: Messages in the Cloud and AirPlay 2. We’ll dive into the messaging update in another post, but AirPlay 2 is a big deal: it adds multiroom support so multiple AirPlay 2 devices from a wide variety of manufacturers can all play the same music around your house. Separately, iOS 11.4 allows two HomePods to play as a stereo pair. Altogether, AirPlay 2 and stereo HomePod pairing bring Apple’s wireless audio system to parity with competitors like Google Cast and Amazon Alexa after years of stasis. Seriously, this is the biggest update to the audio side of AirPlay since it was first announced as “AirTunes” in 2004.

AirPlay 2 brings Apple to parity with other wireless speaker systems

But AirPlay 2 is here now, and Apple tells me the two most specific changes are a bigger buffer so network hiccups don’t interrupt your music and tighter clock sync between devices to enable multiroom support. (You’ve been able to stream to multiple AirPlay devices from a Mac for years now, but AirPlay 2 brings multiroom streaming to iOS devices and the HomePod.) AirPlay 2 also addresses some long-standing annoyances with streaming music from iOS: you can now take a phone call, play videos, and play games without interrupting the music. And moving music around the house via Siri on the HomePod is fairly simple. You just say “Siri, move the music to the living room” or whichever room you prefer, and it’ll stream to that room.

There’s a bunch of third parties lining up to support AirPlay 2 — Bang & Olufsen, Bluesound, Bose, Bowers & Wilkins, Denon, Libratone, Marantz, Marshall, Naim, Pioneer, and Sonos — but there’s a pretty significant catch, as far as I can tell. Other music streaming systems like Google Cast and Spotify Connect treat smart speakers like the little internet-connected computers they are. when you pick a song to play, all you’re really doing is sending a command to the speaker, which then connects to your music service and streams the song directly from the internet.

AirPlay 2 is still very dependent on your phone

That’s not how AirPlay 2 works. It’s still very dependent on your phone. When you stream to a third-party speaker, your iPhone sits in the middle, pulling the music down from the internet and then restreaming it to the speaker. Current AirPlay users will be familiar with the limitations this imposes: if your phone dies or blips on the network or you just leave the house, the music stops.

The only exception is the HomePod, which can connect to Apple Music and stream to other AirPlay 2 speakers independently of your phone. Apple told me AirPlay 2 was only designed to let the HomePod stream directly like this, which makes sense, as the HomePod is an A8-powered iOS device in its own right. But it’s not clear why you’d need the power of an A8 to stream music. It’s not like any competing streaming music devices require such potent chips to work. It’s puzzling, but it tracks with Apple’s general default of putting the phone at the center of everything. We’ll also have to see how AirPlay 2’s multiroom streaming works with Sonos, which has been promising support. I suspect there’s going to be some weirdness here.

Stereo HomePods will sync their bass tuning

Stereo pairing for the HomePod is relatively simple: if you select the same room name as another HomePod during setup, it’ll ask you if you want to pair the speakers. Each HomePod will continue using its individual microphones to tune itself to the room, but you might recall that there’s a special mic hidden inside the HomePod chassis that measures bass response. Those mics will sync in a stereo pair so both speakers apply the same low-end filter. Neat.

The HomePod is also getting calendar support for Siri, so you can ask when and where your meetings are and add events to your calendar. It’ll work with any calendar you add to your iOS calendar app as part of the HomePod’s personal request feature; like other personal information, it’s not available if your phone isn’t on the same network. It would be better if the HomePod could recognize individual voices and only allow your voice to access that sort of information, but honestly, we’re still waiting on multiple timer support here, so don’t hold your breath.

Lastly, I asked if there were any updates that might make the HomePod work better as an Apple TV speaker, and the answer was nothing right now.

AirPlay 2 requires iOS 11.4 on all your devices to work. iPhone owners can update now, while HomePod owners can start the update from the Home app or just wait for it to automatically roll out over the next few days.