Until about a decade ago, the idea of controlling music in every room of your house generally required a costly and complicated custom installed system that would easily cost many thouands of dollars. That changed with the introduction of Sonos, which made the first big breakthrough in simplicity and cost savings. The company's Sonos Play:1 ($199.00 at Amazon.com) speaker -- and the idea of using a phone app as a wireless remote -- brought the buy-in cost down to just $200. 

But with the release of 2015's Chromecast Audio ($35.00 at Jet.com), Google arguably took the lead in ultra-affordable multiroom Wi-Fi audio. And with the Google Home ($129.00 at Overstock.com), it's added voice control to the mix as well. For just $35, £30 or AU$59 per room, the Chromecast Audio is one of the best upgrades you can make to your home's music.  

What is it?

The Chromecast Audio lets you hook up nearly any "dumb" speaker or receiver and stream audio from your phone. It streams any audio from an Android device, and it works with select apps from an iPhone or iPad. (It also can stream from Chrome browsers on Windows PCs and Macs, albeit less smoothly.)

A little larger than an Oreo cookie, the Chromecast Audio is the product of an unholy marriage between a 7-inch record and a hockey puck. The device has a hybrid 3.5mm-optical port and it comes with a very short 5-inch 3.5mm cable to connect to it the Aux input on your hi-fi system, portable speaker or any old boom box. (It also supports full optical digital connections, but you'll need to supply a separate mini-Toslink optical cable.) The only other port on the Chromecast is a Micro-USB port for connection to the included power adapter.

The Chromecast Audio effectively replaces devices such as the Sonos Connect ($350), and when combined with the $129 Google Home it becomes a voice-operated jukebox, too.

What's so great about it?

It's really damn cheap: I can think of no other device this inexpensive that does what the Chromecast Audio does. Sure, you can buy a Bluetooth adaptor, but it will only work in one room, sound worse and cut out as soon as you leave the room. A 3.5mm cable is even cheaper, but then you're physically tethered to the speaker.

It supports all apps on Android, many on iOS: If you're an Android user, you're in heaven as the Audio will play back anything you can play on your phone or tablet. Just tap the Cast Audio/Video button in the Google Home app and that sweet Soundcloud mix tape will start coming out of your hi-fi. Apart from native support there are also plenty of Android and iOS apps with built-in Cast buttons including Spotify, Pandora, iHeartRadio, Google Play Music, YouTube Music and iHeartRadio.  

It keeps improving: In the two years since the dongle's release, the Chromecast has only gotten better, with voice control one of the latest improvements. Of all the Wi-Fi dongles we've tested under $100 this is definitely the easiest to setup. If you want to improve the audio quality you can hook it up to an external DAC or receiver, too -- though the performance is perfectly fine for budget speakers.