GamuT RS7 loudspeaker

Danish manufacturer GamuT Audio's patchy history in the US includes a succession of distributors that failed to establish the brand here. But in 2014 GamuT tapped Michael Vamos to spearhead their own US-based distribution company, which is now energetically promoting the company's products. That change coincided with my auditioning, at the 2014 Rocky Mountain Audio Fest, of GamuT's two-and-a-half-way RS5 tower loudspeaker ($31,900/pair). I was sufficiently impressed that I asked to review it—but then, at the 2015 Consumer Electronics Show, I experienced the RS7. This was the GamuT speaker I wanted to spend some time with, and at the end of March, GamuT's R&D manager, Benno Meldgaard, joined Michael Vamos in setting up a pair of RS7s in my listening room.

The Revised Superior 7
Costing $39,900/pair, the RS7 is basically the same as the RS5, but with a second woofer mounted above the tweeter on the sloped-back baffle, to complete a full three-way design standing just over 4' tall. The midrange driver is mounted several inches below the tweeter, with the first woofer below that. The woofers are loaded with two slightly flared, metal-lined ports, 2" in diameter, halfway up the narrow rear panel.

GamuT's RS speakers use proprietary Scan-Speak drivers, including a version of the high-performance, 1.5" ring-radiator tweeter that I'd first experienced with Mission's Pilastro loudspeaker, reviewed in December 2002. The soft diaphragm is terminated with rubber roll surrounds not only at its circumference, as usual, but also at a central, stationary, sharp-pointed phase plug. A neodymium magnet is used to get high-enough sensitivity. The 7" midrange unit features a radially scored pulp cone 5" in diameter, this treated with what GamuT describes as a "proprietary blend of oils," and terminated with a substantial rubber half-roll surround. The two 7" woofers also have cones 5" in diameter, these made from wood fiber, with flat wooden dustcaps.

The crossover frequencies are specified as 250Hz and 2.5kHz. According to Meldgaard, the slopes of the tweeter and midrange crossover filters are first-order "until they 'meet' each other; at this point [the slopes] begin to become sharper and sharper, in a very 'rounded' manner, to make sure the point of crossover is as invisible as possible." Unusually, the crossover between the midrange unit and the woofers doesn't have a series capacitor to filter the low frequencies from the feed to the former, which is connected directly to the amplifier. Instead, what GamuT calls "a combined serial and parallel crossover" attenuates low frequencies from the midrange-driver signal path. This design is said to avoid any of the phase errors, smearing, or delay that can be introduced by normal crossover designs. Electrical connection is via two vertically arranged pairs of GamuT's Stripped Wire terminals, one pair feeding the tweeter, the other the midrange unit and woofers. As the name suggests, these high-quality terminals accept bare wires; they also accept 4mm plugs.

The slender, elegantly profiled cabinet—from above, it resembles a truncated ellipse—is made in GamuT's own factory. The panels, which are up to 32mm thick, are formed from 21 layers of wood of different thicknesses, curved and glued in a mold, the glue then set using RF energy. This cabinet construction results in a rigid but relatively undamped enclosure, and follows the low-loss philosophy pioneered, for example, by Spendor in the 1970s: Instead of using heavy damping, which lowers the Q of resonances and might therefore make them more audible, the enclosure is left free to vibrate, its behavior then controlled with strategic bracing. Machined into each side panel are two wide, horizontal grooves, for what GamuT says is "optimized cabinet surface behavior."

There is no grille. Instead, two vertical stainless-steel rods flank the drive-units, these supporting 29 horizontal, fabric-covered rubber strings that offer no acoustic obstruction. The enclosure is supported on a massive plinth. The crossover is mounted to the plinth, which comprises two oversize stainless-steel metal plates with a section echoing that of the top panel, the plates sandwiching what appears to be a plate of wood. Four stainless-steel spikes allow the speaker's vertical and horizontal tilts to be adjusted.

Overall, GamuT's RS7 offers a level of fit and finish commensurate with its price.

Optimizing speaker positions with a design that has widely spaced woofers is always a complex business. The goal is to maximize the differences between various critical dimensions—namely, the distances between those low-frequency drivers and the four closest boundaries: floor, nearest sidewall, front wall, and ceiling. GamuT offers a service in which their speaker customers can submit room dimensions and get back specific placement suggestions. In my case, I was fortunate enough to have Benno Meldgaard and Michael Vamos set up the RS7s in my room. (At this price level, this is something the dealer should do.)

I always learn something from watching an expert find the optimal positions for a pair of speakers. Starting from the positions where I'd found the KEF Blade Twos—which preceded the GamuTs—to work best in my room, and using only one loudspeaker at a time, Meldgaard moved each RS7, listening as he went. Having found a position where the sound began to jell, he rocked the speaker from side to side and from front to back, listening for how the low-frequency balance changed as he did so. This led to small changes in position until he declared himself happy. The final setup was slightly asymmetrical: the left RS7's woofers were 2' from the LPs that line the left-hand wall; the right RS7's woofers were 4' 6" from the bookcases that line the right-hand wall; the lower woofer of each speaker was 5' 9" from the wall behind it and 11' 4" from my ears.

GamuT Audio
US distributor: GamuT USA
(888) 252-2499

jmsent's picture

"The soft diaphragm is terminated with rubber roll surrounds not only at its circumference, as usual, but also at a central, stationary, sharp-pointed phase plug."

I don't understand this. Tweeters are generally not terminated with rubber rolls and this one is no exception. The picture shows a one piece coated textile dome assembly, just like every other ScanSpeak and Vifa ring radiator tweeter I've ever seen. Since the large rolls are designed to be the actual radiating surfaces , I think rubber would be the last material you'd want to use for this purpose.
As for the performance...I guess you're being "diplomatic" here..but I see a system with serious flaws in its design. The specs describe this as a 3 way speaker, but the individual driver curves reveal it to actually be a 2-1/2 way system. The so called "midrange driver"isn't really a midrange at all. It's a woofer/midrange, since it is being fed all the spectral energy right up to the tweeter crossover point, including all the bass. At least, the impedance curve gives no indication of an electrical crossover at 250Hz And what exactly is the deal with the huge response dip at the tweeter crossover? Did they run into the well known problem of using a ring radiator tweeter at too low a frequency? It's no secret that 2nd order distortion in this type of tweeter rises quickly under 2.5 kHz, which is why this tweeter performs best when crossed over at or above 3kHz. But then, there's the problem of trying to push a 7" bass/midrange beyond 3kHz. It seems to me this all could have been avoided by using a real midrange driver; e.g., 5" with a true bandpass filter, or choosing a different tweeter that could be crossed in at a lower frequency. To me, this speaker has major flaws, inexcusable at $39,000.

dcolak's picture

That can't be normal, specially for that kind of money?