In many ways Sonos is the Apple of audio. Its speakers and software are easy to use with thoughtful design and attention to detail, it has its own well-developed wireless ecosystem that "just works" and its products are priced at a premium. Until now if you wanted a Sonos sound bar you'd have to spend $700 (£700 or AU$845) on the Playbar or Playbase and optionally another $700 for the Sub. In no way do those qualify as budget speakers.

That's why the $399 (£399 or AU$599) Sonos Beam smart sound bar comes as such a pleasant surprise. It shows that the company, reportedly about to go public, is serious about getting into as many households as possible. If the superb Sonos One smart speaker was the Trojan Horse, the Beam is the invading Greek army.

Just like the One, the Beam has Amazon's Alexa smarts and far-field voice recognition built-in, with support for Apple's AirPlay 2 and Google Assistant coming in July and later this year, respectively. It's no sonic powerhouse, but it offers a wide sound stage, performs quite well with music, and will make your TV sound a hell of a lot better.

The Beam isn't the only voice-activated sound bar, however, and Polk's $299 Alexa-powered Command Bar, which includes a subwoofer, offers serious competition. In my side-by-side listening tests the Polk sounded better than the Beam with a lot of material, but the Sonos beats it for whole-home integration -- Sonos' speciality -- and voice compatibility beyond Alexa. You can also add a wireless sub and rear speakers to the Beam, but doing so increases the price significantly.

Overall the Beam isn't the first sound bar I'd recommend to people who just want their TV to sound better. It is, however, the best for people who already have Sonos in their house and want more, or who want the ability to work with other voice and music ecosystems too. It looks good, it sounds big and it's more flexible than any other smart sound bar on the market, regardless of price.

Design

The wrap-around cloth grille of the Beam -- commonly associated with the company's ultra-budget competition -- comes as a surprise on a Sonos product. Yet, the speaker retains a Sonos look with its plastic top and the touch control panel that debuted on the One.

The pill-shaped Beam is smaller than most other sound bars at just 25.6 inches wide by 2.7 inches high and 3.9 inches deep (68.5 by 651 by 100 mm). You can get it in black or white. Unfortunately, the Beam doesn't include a wall bracket in the box, but the company will sell you one for an extra $59.

While most manufacturers include a remote with their sound bars, this is not the case with Sonos. Instead, the Beam comes with a number of alternative ways to control it, starting with the Sonos app for phones and tablets. The comprehensive setup routine lets you use your TV remote as well as the app, and your voice with the integrated microphones.

The Sonos app has undergone many different changes over the years, but the latest version places the emphasis on music search and the devices in your house rather than a laundry list of the different music services. Given that Sonos has been moving toward third-party control -- such as via Spotify Connect or AirPlay -- this is a welcome move. I preferred being able to play music on a Sonos speaker using the native app, such as Spotify itself, rather than using the Sonos app.

Beamed sound, TV control

Sonos touts the 3.0-channel Beam as its "most advanced sound bar." Its speakers are designed to bounce (or "beam") sound off your walls, and include a center channel with two woofers, two more woofers for left and right channels and a single tweeter. At the front of the unit are two passive bass radiators with another one at the rear. 

The system comes without a wireless subwoofer, though you can add the $700 Sonos Sub if you like. Sonos sells the two together for $1,000 ($100 off the price of both separately), or a "three-room set" that includes a Beam and two Sonos Ones for $650 ($50 off). Two Ones can also be wirelessly paired with the Beam for rear-channel surround effects. A full "5.1" system (Beam, Sub and two Ones) would cost $1,350.

The Beam combines both HDMI and integrated voice assistance for the first time in any sound bar. The HDMI connection includes the CEC control system, which allows some clever gymnastics with compatible TVs -- it lets the Beam turn the TV off and on, using just your voice. It lets you use the TV as an HDMI switch, too. You can plug all your gadgets into your flatscreen and feed the sound bar Dolby Digital 5.1 (though not DTS) sound from your TV's audio return channel (ARC)-capable HDMI port.

Seems perfect, but what if your TV doesn't support ARC?

• Bad news: There's only one audio port on the Beam, and it's HDMI. No optical or 3.5mm input.
  
• Good news: Sonos bundles an HDMI cable and an HDMI-to-optical cable adaptor in the box. So you can connect your TV's optical digital audio output to the Beam.
  
• Semibad news: If you use the adaptor, the Beam cannot turn the TV on and off or control switching.
  

Hearing voices

The Beam comes with Amazon's Alexa assistant straight of the box and the speaker features an improved, five-microphone array designed for use in a home theater environment. It basically works just like familiar Alexa devices such as the (much quieter) Echo -- ask the time, play tunes, operate the blinds -- as well as change volume on the Beam itself. 

Although Google Assistant and Apple Siri support have been promised, they're not available yet so I couldn't test them. Sonos didn't tell me when Google would arrive or whether it will work concurrently with Alexa. But the company did say it will be able to use Siri on your phone in conjunction with Alexa on the speaker at the same time.