Let’s fantasize … about the ideal speaker. While other audiophiles may have their own criteria, here is what my ideal speaker would look like. It would be a point source; be full-range; have a flat frequency response; have even dispersion; have minimal distortion; be of high sensitivity with a high and flat impedance, and thus present an easy load for the amplifier; be visually attractive, relatively small (or at least, not gargantuan), and not cost an arm and a leg. On the qualitative side, it would be neither warm nor analytical; it would have no “grain”; the midrange would have texture and palpability; the highs would be extended but not glary; and it would never lead to listener fatigue. Needless to say such a speaker does not exist and moreover, with current technology, many of the properties of the ideal speaker are mutually exclusive. As such, each designer must decide which properties to focus on, and which to ignore, to a greater or lesser degree.
There are many schools of thought in speaker design and while most are minor variations on a theme, some are “outliers” from the mainstream. One such “outlier” are speakers based on so-called full-range drivers. Of all extant drivers, full-range drivers come closest, along with coaxial designs, of being a perfect point source. In addition, full-range drivers are generally of high sensitivity, easy to drive even with low powered SET amps, and tend to be quick and dynamic sounding. Last but not least, they do not require a cross-over, and thus avoid the complications and artifacts that typically accompany cross-over networks. Unfortunately, the “full-range” moniker is a misnomer, as no driver is truly full-range. Most “full-range” drivers, and thus speakers that use such drivers, are limited in treble extension but their bigger deficiency is in the bass; for this reason a better term for their drivers is “wide bander.” Speaker designers who use wide-banders maximize bass output with cabinets that capture and re-direct the driver’s rear wave. To be sure, some such cabinet designs are more effective than others and by the same token, all wide-bander drivers are not created equal. By a wide margin, the best I’ve heard to date is the Voxativ Ampeggio. However, no matter how good the driver, nor how clever the cabinet design, all designers bump up against the same wiley foe, the one that goes by the make “physics.” Simply put, a single driver, typically 5-8”, can move only so much air, and this can never equal the output of the one or multiple larger woofers found in more traditional designs.
As a result of wide-banders’ bass limitations, a number of designers have opted to use them in conjunction with a traditional woofer or woofers. Such arrangements retain many of the advantages of the wide-bander and may thus be considered “augmented wide-banders,” or augmented full-rangers, for those who hold onto the old and misleading name. But as is so often the case in audio, one benefit brings with it a new problem; in this case it is finding a woofer or woofer arrangement that “keeps up” with the wide-bander, for all too often, woofers seem to lag behind the wide-banders which are known for their speed and punchiness. What to do?
Ralph Hellmer has been an amateur speaker designer for thirty years. For the past five years he has been working on a design that ultimately lead to his first commercial product, the Surreal Sound “Fifth Row” speakers. Ralph’s goals for this speaker were that it was to be dynamic and easy to drive, it had to have fast and tight bass, as well as high spouse-acceptance factor, i.e., it had to have a relatively small profile. To cut to the chase, Ralph achieved his goals, and admirably so, producing a truly incredible speaker.
Form Follows Function
The Fifth Row is a modestly sized speaker. The cabinet is made of high-density MDF which can be painted to the customer’s specification. Optionally, one can order the speaker in Baltic Birch, with pretty much any stain the customer chooses. It is a two-piece design, in which the head portion — which contains the wide-bander — sits atop the bass module via isolation “grippers” that damp vibration. The speaker has curved sides, and the head unit and bass units have the same width (12”) and depth (18”), measured at their widest point, resulting in a sleek appearance. I find them extremely attractive, as have the visitors to my listening room. The head unit is 11” in height and the bass cabinet is 32”, for a total height including footers of 43”. For the MDF version, the head unit weighs approximately 33 lbs. and the bass unit approximately 92 lbs (total 125 lbs).
As is true of most speakers, the bass portion takes up the bulk of the cabinet volume, and largely determines the speaker’s overall size, shape and configuration. Each speaker contains six 10” woofers, arranged one atop the other. The drivers are constructed of a proprietary aluminum alloy, have a high Q, and only 17 grams of moving mass. They use a special one-layer spaced wire voice coil on a kapton former, and are ferrofluid cooled. The spaced wire allows cooling to occur almost all the way around the wire, and any heat build-up is dissipated by the ferrofluid. As a result the coils stay cool, and the drivers are claimed to exhibit only 1dB dynamic compression even with close to 1000-watt transient pulses. Ralph further explained that ferrofluid plays an additional role, that of creating a fluid bearing. As a result the drivers have no need for a spider, which further enhances transient response.
The woofers are slot loaded such that three woofers are visible from the front, and the other three from the rear. Ralph explained that slot loading lowers the driver resonance resulting in lower frequency extension without adding mass. Though all the woofers are oriented with their cones facing downward, they are wired with alternating phase so as to eliminate vibration. The drivers’ vertical stacking arrangement necessitated a cabinet that consists of a series of individual “rings,” themselves stacked atop one another. This arrangement is both attractive and strong, and helps eliminate vibrations. The plates are secured with four vertical threaded rods, one in each corner, that while not visible, provide further support and stability. To the bottom of each speaker are attached two outriggers which contain adjustable spikes; these provide stability, and the ability to adjust the height and rake of the speakers. The woofers are amplified by their own external amplifiers included in the price, and thus have their own binding posts. I will have more to say about this below.
On top of the bass cabinet sits the “head unit,” which contains an 8” wide-band driver from Tangband. Ralph describes it as “semi-cardoid transmission line.” It has solid walls on three sides, while the rear is a perforated grill. The interior is stuffed, though I am uncertain of the composition of the stuffing. The binding posts are on the bottom rear of the cabinet.
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