The Gershman Sonogram Loudspeaker

Hidden Virtues...

The one thing you can safely say about Gershman speakers is that they’re decidedly, obviously, gloriously distinctive. They don’t look like other speakers, they don’t adopt the same approach or technology as other speakers and that’s why they so often appeal to people who find those other speakers wanting. Whether it’s the tapered elegance and unusual driver disposition of the Gap 828 or the nested cabinet design of the Black Swan, one look at a Gershman and you know it’s not a “me too” product. Which made the Sonogram, the company’s new and more affordable model, something of a shock when I first saw it at the Rocky Mountain Audio Fest. A slightly squat, resolutely rectangular floorstander, it could only be described as – well – normal! But fear not, looks can be deceptive.

The first clue comes when you remove the grille, underneath which lurks a full three-way driver line-up, including a custom 205mm bassunit sporting Gershman’s trademark yellow cone. So that’s why the cabinet is wider than the fashionably slim frontal profile found on the competition. Next, you pick it up – or try to. The Sonogram weighs more than you expect it to – a lot more. Now, I know that Eli Gershman likes to put a lot of material into his speaker cabinets, but there’s definitely something different going on here, which isn’t obvious to the naked eye.

Sure enough, the internal construction is anything but conventional. It’s also impressively simple in concept, in a “Why didn’t I think of that?” sort of way. Take one look at the Gershman product range and you don’t have to be a genius to spot the theme; tapered cabinets designed for rigidity, low resonance and to reduce internal standing waves. The problem is that such complex cabinets are difficult and expensive to produce, a big no-no if you are designing a more affordable model. There again, so is losing all the qualities that make your established designs so popular…

The solution to this dichotomy was surprisingly simple and elegant. The front, sides and top of the Sonogram are of standard, chamfered edge MDF construction. The rear baffle is the clever bit. Viewed from above, this has a triangular section, the flat rear keeping the box conventional in appearance, the sharply angled inner faces breaking up standing waves and adding substantial bracing to the cabinet (see the accompanying diagram). The front, side and rear panels are in turn braced by conventional horizontal members, creating a rigid and heavily triangulated structure. If you are feeling confused, the internal construction is shown on the Gershman web-site; one glance and everything will become clear. The end result is a cabinet that is utterly conventional in appearance, making it cost effective to finish and pack, yet its internal arrangements offer similar sonic advantages to the more extravagantly shaped cabinets used on the more expensive models. The hidden nature of this solution also helps to explain the name…

The bass driver is reflex loaded by a large slot port positioned at the bottom of the rear baffle, an arrangement that delivers substantial bass, another Gershman trademark and one that extends to 28Hz in this case: midrange is handled by a Morel 55mm doped fabric dome operating between 350 and 2000Hz, with a 25mm soft dome filling out the upper register. The cabinet stands on a small plinth and large, adjustable cones are provided for leveling. A single pair of binding posts is all that’s provided, following the recent trend away from bi-wiring. Efficiency is quoted at a realistic 89dB, with a reasonably flat 6Ohm impedance curve making for a manageable paper load, although in practice, speakers with this much bandwidth demand an amplifier capable of getting a grip on their nether regions and, like other Gershman designs, the Sonogram really responds to quality power. I employed various amps throughout the listening period, but large andsolid-state always seemed to tick the right boxes, as well as offering the headroom required for realistic levels; if the Sonogram has an Achilles’ heel it’s the way it shuts down at low listening level. The speaker readily reflected the benefits of high-end designs like the RADIA or Belles MB-200 monos, but the Electrocompaniet ECI 5, with its solid 120 Watt output proved to be the perfect price/performance partner. The Sonogram looks and sounds better with the grilles removed, the review pair arriving in an attractive pale wood veneer, a red stained option being the other alternative. You can have various piano finishes too, but they cost a fair bit more. The standard finishes are priced at a very reasonable $3700 US, meaning that they would probably cost just the right side of £3000 in the UK.

With any speaker that reaches well below 40Hz, positioning will be critical, and the Sonogram is no different. Both distance to the rear wall and toein demand considerable care and attention if you are to get the weight, balance and stereo perspective just right. On my wooden floor, with the cones stood on finite elemente footers this was simplicity itself (these speakers definitely let you hear the result of each shift) but I’m not sure I’d fancy repeating the experience with carpet. Once placed, you’ll also need to level them. With that done you’ll start to hear what these speakers are all about. First up is that bass. Deep and weighty, get the positioning right and it will also be beautifully integrated, quick, agile and surprisingly powerful – surprising in the musical sense that is. I’ve never been over fond of the Reiner/Chicago recording of the Beethoven 5th, finding it all too often turgid of tempo, inflexible of phrasing. Playing it on the Sonograms demonstrates that the problems experienced lie with the systems used rather than the recording or performance. Get the bass wrong (too tight, not enough energy) and the music loses its sense of drive and expectancy. The Sonograms get it right and the result is bold and involving, with that delicious contrast between authority and delicacy that makes the work so special. Orchestral tuttis have real substance and body, Reiner’s dynamic shadings are beautifully judged, the internal contrasts enhanced by the sense of space and placement…