The Playbar does deliver a lot of midbass, so the sound balance is very rich and full. Dialogue sounds pleasantly warm, but intelligibility is a little below par in the standard playback mode. Thankfully, there's a Speech Enhancement feature, which actually boosted intelligibility quite a bit. The Playbar also has Bass, Treble, and Loudness controls, but they were fairly subtle and only slightly altered the sound balance of the speaker.
On the plus side, the Playbar's richly balanced sound is a big step up from the speakers built into TVs, and the Playbar's enveloping sound will impress most buyers. On the other hand, the Playbar doesn't produce any truly deep bass. Compared directly with the Speakercraft CS3, the Playbar's bass definition was rather soft and muddy, while the CS3's bass definition, dynamic range, and overall clarity surpassed the Playbar's. The CS3 also does virtual surround well, but the Playbar's is better and projects sound farther forward into the room.
The Playbar is rather pricey for sound bar without a subwoofer, so we also compared it directly with the Harman Kardon SB 16 ($600 street). The SB 16 comes with a subwoofer that's huge by sound bar standards and, unsurprisingly, it delivers much deeper and more powerful bass. The speaker's clarity and detail easily also outdid the Playbar's on a war movie like "Black Hawk Down." The explosions and gunfire in large-scale battle scenes were more exciting on the SB 16; the Playbar sounded muffled by comparison.
Next, we added the Sonos Sub ($700) to the system, which not only added bass, it significantly improved the Playbar's sound. The bass firmed up and the speaker's midrange detailing was enhanced. The Sonos Sub is smaller than the SB 16's sub, but sounded equally powerful. The Playbar-Sonos Sub combination was better, but still didn't match the SB 16's clarity.
To finish up, we listened to the ultimate Sonos home theater experience, adding a pair of Sonos Play:3 ($300 each) speakers as surround speakers. (In this configuration -- the Playbar, two Play:3s, and one Sub -- only one of them needs an Ethernet connection; the rest are wireless except for the power cord and the connection to the TV.) The additional speakers generated a somewhat more spacious, room-filling sound, but it lacked the spatial accuracy we get from a traditional receiver-based 5.1 home theater system. Jazz singer Patricia Barber's excellent music-only 5.1-channel "Modern Cool" Blu-ray had surprisingly little surround sound effect on the Sonos, which isn't what we're used to on other systems.
About that "surround" sound...
The relatively mild improvement from adding the Play 3 speakers didn't make much sense, until we dug a little deeper into the technical details of how the Playbar works. Feel free to skip this section if you don't care about the geeky particulars.
The Playbar can decode two types of audio signals: Dolby Digital and stereo PCM. If the Playbar receives a Dolby Digital signal, it can create the true surround-sound mix that's included with the movie, TV show, or video game. If the Playbar receives a stereo PCM signal, it will still create surround-sound effects, but they'll be simulated using its own processing rather than the original surround mix.
The problem is that in the vast majority of cases, the Playbar will never get a true Dolby Digital signal. That's because the Playbar requires you to route audio signals through your TV and most TVs "dumb down" incoming surround signals to stereo via their optical output. We tested several TVs in the CNET lab and only one of them (Sony's high-end XBR-55HX950) passed a true Dolby Digital signal to the Playbar via its optical audio output. In every other case, the TV would pass a stereo PCM signal to the Playbar, which then created a pseudo-surround mix based on its own processing.
Furthermore, there's no way of getting a true surround mix from a Blu-ray or DVD that has a DTS (rather than Dolby) soundtrack. Even if there's a TV that will pass a native DTS signal to the Playbar, it doesn't have the decoding to take advantage of the true surround mix. (None of the TVs we tested passed DTS signals, for what it's worth.)
And the kicker is that the Playbar sounds dramatically better when it receives a true Dolby Digital signal. Not only with the Play:3 surround speakers, which then produced excellent surround effects, but also with the Sonos Sub, which had much clearer bass definition. In our test setup, we were easily able to flip back and forth between the true surround mix and the Playbar's simulated surround mix, and the difference wasn't subtle.
The practical outcome won't bother less critical listeners; the Playbar still does a better job of creating a big soundstage than the vast majority of sound bars, even if it's not the "true" surround mix. But it's still bothersome to know that the Playbar can sound significantly better, especially with additional Sonos components, but is hamstrung by annoying technical issues (albeit ones that are the fault of the TV). As it stands, Playbar owners with the Sonos Sub or Sonos Play: 3 surround speakers or both won't be able to consistently hear the sound the system is capable of.
What are the alternatives?
The Playbar is part sound bar, part digital audio system, so there's no one single product that offers precisely the same experience. However, it's not hard to put together a system that sounds better and offers nearly same functionality for less money.
The best alternative is the Speakercraft CS3 ($600). It sounds better, it looks just as good, and with built-in Bluetooth, you can stream audio from any app on your smartphone or tablet, regardless of operating system. Similarly, if you have an iPad or iPhone, you can pair up an Apple TV ($100) with the Harman Kardon SB 16 ($600). Not only will you be able to stream audio from any app via AirPlay, but the Apple TV can also access music stored on a computer running iTunes.
Both of those alternatives get to the same truth: if you don't need Sono's excellent multiroom flexibility, AirPlay and Bluetooth actually duplicate a lot of the Sonos experience these days. Sure, Sonos is still a slicker system, especially if you have a large personal library of music, but for the average buyer Sonos is overkill.
If you're set on Sonos, you can also easily pair up a Sonos Connect ($350) with the Harman Kardon SB 16. The Harman Kardon includes a wireless subwoofer, so while that combo ($650) is more expensive than the Playbar on its own, it's less than half of the Playbar and Sonos Sub combo ($1,400 total).
Conclusion: Not for everyone
The Playbar has its charms. It's well-designed and innovative, with great virtual surround effects that you can't get elsewhere without spending more. Sonos also has delivered on truly painless setup for both the sound bar and its digital music software, which is no small feat.
But ultimately we can't love the Playbar because, well, we wouldn't want to listen to it every day. It sounds like no other sound bar and, since our tastes skew purist, its processed sound gets tiresome over time. It's easier to live with the Playbar for movies and TV, but for a sound bar that's so focused on music -- this is Sonos, after all -- we wanted it to sound a lot better with stereo music. Especially for $700.
If you're invested in the Sonos ecosystem and aren't a purist about sound quality, the Playbar is a solid choice as a way to get better sound out of your TV. But for Sonos newcomers, the Playbar isn't a great entry point to the company's line, as it's less impressive as a standalone product.