Big Picture Big Sound

ZVOX IncrediBase 575 HSD Single-Cabinet Surround Sound System Review

By Chris Chiarella
Edited by Chris Boylan

The Base with Bass

ZVOX Audio has been manufacturing great-sounding single-box loudspeaker solutions for several years. The products have grown larger, more powerful and more elaborate, but the fundamental technology inside has remained the same, using the company's proprietary "PhaseCue" circuitry to make the audio appear to come from beyond the confines of a single cabinet. In my experience, going back to the first generation, it has always worked extremely well.

Almost as important to the ZVOX story as the quality of the sound is the simplicity of setup and use. One box is just plain easier than five or six, and any trace of frustration is conspicuously absent from an owner's manual that can more accurately be described as a leaflet, up from the single sheet which accompanied their very first products. And most of this is taken up by artwork, warranty information and the usual "don't use in the bathtub" safety-grams.

The rigid full-width grille gives the 575 HSD a clean, distinctive appearance.

Now, in the age of high definition, the technical standards of TVs and other gear are forging ahead, with digital outputs becoming the norm. The ideal configuration for ZVOX products has always been connected to the variable audio output of a television, to reproduce the audio of any source component being fed to the display while relying upon only the TV's remote control to adjust master volume. But with a fiberoptic digital output a mandatory feature on any television that calls itself an "HDTV," and with digital outputs now ubiquitous on cable boxes, satellite receivers, gaming consoles, DVD and Blu-ray players, it's time for ZVox to tap into that digital goodness, which they have done in the top-of-the-line ZVOX Incredibase 575 HSD.

Analog Virtual Surround Sound...?

Although the "HSD" models do feature both fiberoptic and coax digital intputs, they also include standard analog inputs, and the key to their magic actually lies in the analog -- not digital -- domain.  The "secret sauce" in ZVOX products is their proprietary PhaseCue technology, an analog departure from the digital processing used by most virtual surround sound solutions on the market. It creates the illusion of "5.1" by widening the soundstage in a just-crazy-enough-to-work manner.

The left speaker inside the 575 HSD plays the left-channel signal as intended, plus out-of-phase information from the right channel. This would be the left minus the right, as generated by the PhaseCue circuitry. The level of the PhaseCue effect, how much out-of-phase information is being created in real time, is determined by the user with the help of the PhaseCue up/down keys on the remote, right beside the volume controls. This is a welcome change from the PhaseCue knob which was located on the rear or front panel of older ZVOX models. A lower setting yields a more natural sound, while nudging up the processing broadens the dispersion and, when reinforced with the available bass, creates a more convincing--albeit virtual--surround soundfield.

The results trick the ear into believing that the sound is originating from different points around the room, not localized to the bi-amplified speaker array inside the 575 cabinet. ZVOX is not attempting to go toe-to-toe with a true 5.1 channel system, or even a comparably priced HTiB, which arguably trades off discrete multiple channels for typically small, inexpensive bundled loudspeakers. Instead, the 575 HSD concentrates on overall sound quality and harmonic accuracy, with the simulated surround sound coming as a bonus.

The main speaker array of the 575 HSD consists of five long-excursion drivers with shielded ferrofluid and neodymium magnets, behind a rigid, full-width front grille. The ZVOX "Infinite Compliance" system connects the outer two main speakers with an acoustic tube which further aids the illusion of bigger sound Low frequencies are handled by two downward-firing 6.5-inch high-mass, long-throw powered subwoofers inside the hefty, rear-ported MDF cabinet. The interior volume of this acoustically neutral wooden housing is said to be the equivalent of a 14-inch cube subwoofer, and the bass performance is touted as accurate down to 35Hz. Want to really piss of the neighbors? A standard sub pre-out port is also provided on the rear panel for connecting an additional powered subwoofer.

With A Name Like "IncrediBASE," Where Do You Think It Goes?

The 575 HSD is a lot bigger than a "soundbar," and it sounds a lot different, too.  Yet it's smaller than five good loudspeakers plus a subwoofer and amplifier. From the minute we unbox it and put it into position (actually, we might want to ask a muscular friend to help), we're faced with a variety of stipulations. The "IncrediBase" is designed, and even named, to go one place: under the TV. But we do need to consider weight of the TV (140 pounds maximum) and its size (nothing with a base wider than 26 inches or deeper than 14).  Luckily these parameters include most flat panels with screens ranging from 37 to 65 inches. The hand-built, cross-braced cabinet seems pretty solid to me, and the top surface is covered by durable black vinyl. Of course, the stand or credenza where TV and ZVOX will reside needs the requisite dimensions to accommodate the four clear rubber feet of the unit.

The ZVOX 575 HSD where it belongs, under the TV.

The rear jack pack can be a little confusing at first glance, looking as it does like two pairs of side-by-side red-and-white RCA inputs. In actuality, it's one set of analog stereo inputs on the left, the top right port is the subwoofer output, and the bottom right is the coaxial digital in. The optical input is clearly marked and can only be one thing, although the opening is quite narrow and will only accept the most compact of fiberoptic plugs. At first I was unknowingly using one that was too fat and I thought it was secure, but I was getting no signal. This being the case, and a major selling point for the 575 HSD, perhaps future shipments might include an acceptable optical cable in the box...?

The ZVOX 575 HSD's digital inputs can handle Dolby Digital or Linear PCM input, and the better the signal, the more dramatic the results. Just remember to turn off the TV's internal speakers, if applicable.

With A Name Like "INCREDIBase," How Do You Think It Sounds?

When playing the Dolby TrueHD soundtrack of the Star Trek Blu-ray, my PS3 correctly passed the 640 KBPS Dolby Digital 5.1 companion track over its fiberoptic digital output, and the effect was outstanding. Despite some caveats by the ZVOXers in their FAQs and instruction guides, dialogue was always exceptionally clear -- even with PhaseCue surround engaged.  Furthermore, the distribution of the ample bass here was most excellent, smartly using the reflectivity of the tabletop to its advantage, and I really felt it.

Turned up full however, and depending upon the material, the sound can become unnaturally boomy, so adjust with care. Just the eight up/down buttons on the remote provide many ways to customize the sound to our liking, so the time we dedicate to experimenting will be well-spent. For comparison, I dialed down the PhaseCue completely, and the experience was still remarkably intense and room-filling, favoring the front soundfield of course but not conspicuously so.

Ample connectivity around back, just be sure to read the fine print.

I switched over to DVD to properly assess some of my go-to soundtracks. On Master and Commander, you could almost convince me that voices and debris were indeed coming from discrete speakers during the first battle. The directionality of the cannonfire and of people scrambling around the deck of the H.M.S. Surprise were undeniably strong. Again, any unwanted characteristics can be managed by trial and error with the remote.

I mean, driven at 100% volume, or with the bass output at maximum--which isn't really necessary for a small- to medium-sized room--the 575 HSD will begin to distort unpleasantly.  But you could say the same about most systems, even the most expensive ones, if driven past their limits.

The spaciousness afforded by the 575 HSD hardware and the PhaseCue effect, while not necessarily akin to an invisible pair of well-dispersed bi-pole or di-pole surrounds behind me, can be splendidly organic, without the audible harshness found in some digital processing. Audio seems to emanate from everywhere at times, the air itself alive in a very believable fashion, with a remarkable illusion of height even, all from this wide, flat box.

The difference, the improvement that properly tweaked PhaseCue can make in a surround-intensive sequence like Gabriel's rescue in The Patriot is astounding. This scene is all about directionality, not only for the many gunshots but in more subtle cues, as when Mel throws his tomahawk, an effect which is all but silent when PhaseCue is set to zero.


  • Outstanding sonic performance from a single box
  • A serious piece of home theater gear, big and remarkably well-crafted
  • Handy little remote offers excellent audio control and fairly simple operation


  • Connections at the back panel can be a little confusing the first time
  • Colored, blinking indicator lights offer some feedback on remote operation - more would be welcome

Final Thoughts

Although it may be abundantly clear by now, I enjoyed my time with the Incredibase 575 HSD and found it to offer outstanding sound quality and performance for such a discreet, easy to use component.  If you crave the aforementioned performance but don't care about the digital connectivity, there is a less-expensive analog-only model available (Incredibase 575 without the "HSD" designation). But those digital inputs do provide more flexibility as well as enhanced sound quality on the ZVOX 575 HSD, so we'd recommend splurging a bit more to get the best that ZVox has to offer. "IncrediBase," indeed.

Manufacturer's Specifications

  • MSRP: $749.99
  • Dimensions: 36" W x 5" H x 16.5" D
  • Main Drivers: 3.25" (5)
  • Subwoofers: 6.5" (2)
  • Max Total Output: 133 Watts
  • Color: Black
  • Net Weight: 39 pounds
  • Warranty: 1 Year, Limited Parts and Labor


  • Digital Optical Audio input (1)
  • Digital Coaxial Audio input (1)
  • Analog Stereo input (RCA-type, 1)
  • Subwoofer output (1)

What's in the Box?

  • Analog stereo (RCA-type) cable
  • Remote control
  • Power cord
  • Operations Manual/Safety Instructions leaflet

Manufacturer Contact Information:

ZVOX Audio
17 Columbia Street
Swampscott, MA  01907

ph: 866-367-9869


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