Cast is the core technology behind Chromecast - the standard used by the dongle and its compatible apps to get video from one place to another. Now Google has announced an audio-only version, complete with several hardware and software partners.
That means you'll be able to beam music from Google Play Music, Rdio, Pandora, NPR One, Deezer and other supported apps to Google Cast-ready speakers. Sony, LG and Denon are among the companies on board on the hardware side, and the first sets of speakers will arrive in the US in spring.
Spotify is the biggest name missing from the announcement - presumably Google is still trying to persuade it to get involved - but there seems to be enough initial momentum to give the likes of Apple and Sonos something to think about.
Cast your nets
The system will work just as Chromecast does now: one tap will send the audio from your phone to the speakers, and the relevant tunes will be pulled straight from the cloud rather than the connected device. That reduces the strain on your smartphone or tablet and means your anthems won't be interrupted by a loud SMS alert.
Google promises that additional partner brands are going to be arriving later in the year, ready to "join a growing Google Cast ecosystem which includes more Android TVs, game consoles and set-top boxes." As yet there's no indication that we'll get an audio-only version of the Chromecast dongle to add the functionality to older speakers.
The functionality is very similar to Apple's AirPlay, but the good news is that you might not have to choose between them - Sony is one manufacturer who has said that its speakers will support both platforms in the future.
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