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. 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.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 \t Pioneer Speaker Base , currently our favorite of the breed.DesignWhen shopping for a sound base you'll quickly find their overall design aesthetic is fairly minimalist, and while models like the \tLG 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 \t 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.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.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.FeaturesThe 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.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.