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Zvox SoundBase 670 review: Great speaker for boosting dialogue

The Zvox SoundBase 670 is a well-built speaker base that is great at boosting the intelligibility of TV broadcasts, but not so great at playing music.

Ty Pendlebury Editor
Ty Pendlebury is a journalism graduate of RMIT Melbourne, and has worked at CNET since 2006. He lives in New York City where he writes about streaming and home audio.
Expertise Ty has worked for radio, print, and online publications, and has been writing about home entertainment since 2004. He majored in Cinema Studies when studying at RMIT. He is an avid record collector and streaming music enthusiast. Credentials
  • Ty was nominated for Best New Journalist at the Australian IT Journalism awards, but he has only ever won one thing. As a youth, he was awarded a free session for the photography studio at a local supermarket.
Ty Pendlebury
5 min read

As Zvox will gladly tell you, the company started the sound base movement back in 2003, and it's taken till 2014 for the mainstream to catch up. A sound base is designed to sit under a TV and improve its typically terrible sonics.


Zvox SoundBase 670

The Good

The ZVOX SoundBase 670 is well-built and will hold TVs up to 70 inches in size. Its dialogue mode really improves intelligibility, which can be a real savior for the hard of hearing. Movies sound good, and the base has plenty of inputs.

The Bad

The cheaper Pioneer Sound Base has better overall sound, especially for music. It has uninspiring looks, the bass is set too high in default modes, and the faux-surround modes can't be completely turned off.

The Bottom Line

The Zvox SoundBase 670 is a well-built speaker base that is great at boosting the intelligibility of TV broadcasts, but it's not the best value.

The SoundBase 670 is Zvox's newest sound base and is designed to accommodate larger televisions (up to 70 inches). It offers the usual features -- Bluetooth, Dolby Digital decoding -- plus a large number of inputs. The No. 1 thing it's good at? Making dialogue more intelligible with its AccuVoice mode.

If you're looking for something that's an all-rounder, though -- which is foreseeable due to the high number of inputs this speaker accepts -- then you'll be disappointed. Music is subjected to an automatic "wide" mode and movies lack the punch of the much cheaper Pioneer Speaker Base , currently our favorite of the breed.


Sarah Tew/CNET

When shopping for a sound base you'll quickly find their overall design aesthetic is fairly minimalist, and while models like the LG SoundPlate buck the trend, the Zvox SoundBase is sticking with what it knows. Yet another black slab, the SoundBase 670 is still distinctive due to its sheer size: it's definitely the largest speaker of its type I've seen, at 36 inches wide and 16.5 inches deep. It's modestly tall, too, at 3.5 inches high.

This bulk means that it can hold much larger TVs than the 55-inch models these products usually support, and the Zvoz is designed to hold up to 70 inches. If you find yourself in the company of a monstrous TV like the Sharp 80-inch LE650 , then Zvox has you covered with the SoundBase 770 ($700). Or if your needs are more modest, the 60-inch compatible SoundBase 570 is $400.

Sarah Tew/CNET

The front of the box has minimal controls -- power, vol +/- and input -- and hidden under the non-removable grille is a four-character display that activates on changes and then turns itself off again.

Sarah Tew/CNET

The remote control is a credit-card-style model that includes all of the necessary controls, including buttons for the Accuvoice and Output Leveling mode. It tries to give a nod toward ergonomics with a beveled back and a mute and volume control on the bottom.


The Zvox SoundBase 670 is a 3.1-channel system that includes a center, left/right and three "subwoofers" hidden underneath. It can decode Dolby Digital soundtracks, as it is designed primarily to hook up to your TV with an optical digital cable.

Sarah Tew/CNET

Not content with simply inventing the sound base concept, Zvox aims to position its newest product partly as a hearing assistive device. The dialogue enhancement feature on the 670 now comes with a new name -- AccuVoice -- and Zvox says it is designed to help the elderly and people with hearing difficulties when watching television. In partnership with this comes Output Leveling (OL), which is supposed to prevent commercials from being "too loud."

Unlike other products that enable you to add pseudo-surround effects, with the SoundBase you can't turn them off to listen to true stereo. It comes with three "surround" modes. One boosts voice with a "very low level of PhaseCue virtual surround," a second adds medium amounts of surround effects (Zvox recommends it for most content) and a third, said to be for movies, adds the most surround effects and boosts bass. There's no "Off" mode, however.

Sarah Tew/CNET

While the competitive Pioneer Sound Base is great, it's not the best choice if you want to plug more than two different sources into your TV. This is where the Zvox shines. It offers three digital inputs (two optical, one coaxial), three analog inputs including a front-mounted 3.5mm jack plus Bluetooth with aptX. Unusually the speaker base also includes a subwoofer output and a stereo output.

On the other hand most people don't need all those inputs on a sound bar, and in fact we recommend using your TV as a switcher most of the time.


I tuned the SoundBase when watching movies, and like the Vizio SoundBase before it, bass was up way too high, though not as catastrophically. I experimented with using the first surround mode for music but found that it unreasonably boosted vocals, and even adjusting bass and treble didn't help it sound natural. In the end I used the second surround mode for most content, including music and most TV broadcasts. I found I needed to reduce the bass by four (out of six) to get an even mix when listening in Surround 2 mode.


Like most of these products, the SoundBase's talents lie toward movies and TV and not music. Its dialogue reproduction, particularly with AccuVoice enabled, is among some of the most natural you'll find in a product of this type. But things get a bit less entrancing with other parts of a soundtrack.

AccuVoice definitely makes voices more intelligible and is helpful for content that isn't meticulously mixed in a post-production studio, like live TV. However it wasn't as successful as communicating a live broadcast of the band 30 Seconds to Mars, which robbed the music of its low-end tom-tom energy and vocal immediacy -- even when I turned off AccuVoice. Switching to the Pioneer Sound Base gave the music back the rich overtones the broadcast had been missing.

While Output Leveling (OL) indeed made ads less booming, it also had unexpected effects on dialogue. The setting reduced male voices, on "Judge Judy," for example, to become too chesty and less understandable, and also reduces the volume overall. When switching to an action movie, the effect compressed the audio to sound like a TV speaker, though with extra clarity than most. However I found that using AccuVoice and OL together was acceptable, adding some intelligibility back into vocals, and would be suitable for late-night listening.

If you're looking for a speaker that can give you big movie thrills, the Zvox does a passable job, but it won't blow you away. The Pioneer is capable of a much greater dynamic range when going from the whispered dialogue to the explosions of the bridge attack scene from "Mission: Impossible III." Using a sound meter, I found that the Pioneer was capable of going up to a maximum of 102 decibels from a base of 70, almost half as loud again as the Zvox (96dB) from the same loudness. There was also some port noise or "chuffing" audible from the rear ports of the Zvox after big explosions.

While acceptable for a unit of its type, music replay again wasn't as dynamic or "present" as on the Pioneer. Seemingly due to the added surround effects in Surround Mode 2, the Zvox lacked a solid soundstage and some instruments would pulse subtly in and out. Listening to loud guitar music via the Bluetooth connection was also disappointing -- partly as Bluetooth is pretty bad to begin with -- but the unit's midrangey response rendered Future of the Left's guitar rage anthem "Sheena Is A T-Shirt Salesman" overly caustic. It made the guitars stick out in a way that other speakers don't, and obscured the already distorted vocals.


I was excited about the Pioneer Sound Base in a way I'm not about the Zvox. Its sound is simply not as thrilling. The Zvox's main talent is improving dialogue intelligibility, and if you're not looking at pushing its limits it will work very well at improving your TV sound. At $500 it's a decent deal, but if you don't need the inputs or the dialog mode, the Pioneer is a much better buy.


Zvox SoundBase 670

Score Breakdown

Design 7Features 8Sound 7Value 7