GOLDENEAR SUPERSUB X
Have you ever had a subwoofer attack you? Well, by ‘attack’ I actually mean ‘move menacingly towards you.’ I have. It was a bit scary. What was happening was that the drivers in the subwoofer were generating so much force that the cabinet was vibrating more in one direction than the other, which caused the cabinet to move towards me… or at least it did until I turned the volume down, which stopped it in its tracks.
GoldenEar is obviously aware of this phenomenon and has taken two steps to avoid it happening with its newest subwoofer, the SuperSub X, which also happens to be the smallest and lightest subwoofer in its ‘SuperSub’ series… and so would be—theoretically at least—the most likely to move of its own accord.
The first design approach involves actively preventing any unwanted driver movement from causing the cabinet to move. In the SuperSub X this is achieved by mounting the two active drivers on either side of the cabinet, so that any unwanted motional forces they create are equal and opposite… and, as all erudite readers of this august journal would be aware, Isaac Newton’s Third Law of Motion states that for every action there is an equal and opposite reaction, so that two forces that are equal and opposite each other will cancel each other out. GoldenEar has left nothing to chance, however, so it’s also fitted four extremely compliant flexible rubber feet to the SuperSub X. These not only absorb any remaining unwanted motion, but also keep the down-firing passive radiator the correct distance from the floor so its output will properly contribute to the soundfield.
The active drivers inside the GoldenEar SuperSub X have circular cones made of strong, thick, paper pulp, with large paper pulp dustcaps. The mounting hole diameter of each driver is 205mm but the effective diameter of each cone is 165mm. There are two other ‘drivers’ inside the SuperSub X, but they’re passive radiators, lacking voice-coils and magnets, and are therefore driven not by your amplifier’s electrical power, but by the air pressure differences inside the cabinet caused by the movement of the two active drivers.
The two passive radiators (GoldenEar calls these units ‘quadratic planar infrasonic radiators’) are rectangular-ish in shape with
a long side of 220mm and a short side of 190mm. Like the powered drivers, the passive radiators are mounted on opposite ‘sides’ of the cabinet, but this time the ‘sides’ are in fact the top and bottom of the cabinet, with one driver facing upwards and the other facing downwards. The upwards-facing driver is protected by a black metal perforated mesh grille (as are the side-firing active drivers) but the down-facing driver is grille-free.
Using passive radiators to harness the otherwise wasted energy from the rear of the driven cones is a very sensible approach that enables higher sound pressure levels to be generated than would otherwise be the case, and extends the low-frequency response further downwards than would otherwise be possible. According to GoldenEar’s Sandy Gross, using passive radiators (rather than a bass reflex port) enables the SuperSub X to, in the company’s words, ‘ perform like a well-tuned transmission line but with superior transient performance and control.’
We like that it enables the cabinet to be sealed, which means that common small household pests (cockroaches, mice… even possums!) will be unable to use the warm, cosy interior of the subwoofer as a home (as they have been known to do with bass reflex enclosures). The amplifier inside the SuperSub X is a Class-D design rated by GoldenEar as having a power output of 1,400-watts. Again, according to Sandy Gross, its circuit design is based on circuitry that was originally developed for GoldenEar’s Triton One powered loudspeakers (where the low-frequency section of the speaker is powered, but the midrange and high-frequency sections are passive). I know that many audiophiles have it in for Class-D designs and, when we’re talking about wideband amplification, particularly at high frequencies, I agree that Class D has its peculiarities. But there’s absolutely no reason not to use a Class-D amplifier in a subwoofer, because it’s never going to be called on to deliver any high frequencies and the load it has to drive is known, so the Class-D circuit can be optimised for it. So in fact, a subwoofer designer would be insane not to use a Class-D amplifier… plus, of course, an SMPS to supply it with voltage and current.
You should not be surprised to learn that the controls for the SuperSub X are on the rear panel, because it’s the only surface they could be on—except for the front panel of course, and you wouldn’t want to destroy that beautiful expanse of piano-black gloss paint, would you? The essential volume and crossover frequency are rotary controls with a very smooth, silky action and a rather gorgeous shape. Why settle for circular control knobs when you can have ones like this? The crossover frequency control enables adjustment from 40Hz to 150Hz, with a single midway calibration point at 95Hz.
There are only two inputs—left-channel and right-channel—both via gold-plated RCA connectors. If you’re using an LFE output from your amplifier or receiver, it should be plugged into the left-channel input. A switch alongside the crossover frequency control lets you switch between left/right in and LFE in. Alongside this switch is a chameleon LED that indicates power status. It’s marked both ‘Auto’ and ‘On/Off’ but you have no other control over the delivery of power to the SuperSub X, because there is neither a mains power switch, nor a secondary one: Once you have plugged in the power cord, the SuperSub X automatically powers up, after which you have only the options of using the ‘Auto’ mode, so that when it detects an audio signal at one or the other of its inputs, it will switch itself on and then stay on until it has not detected any type of audio signal for around 20 minutes, after which it will switch to standby mode, or the ‘On’ mode, in which it stays on all the time.
So the only way of ensuring the SuperSub X is truly ‘off’ is by switching the mains power off at the 240V wall socket. Also missing is any type of phase switch—either a two position (0/180°) toggle switch or a rotary (0–180°) control. This will very slightly restrict your ability to correctly tune the SuperSub X to integrate perfectly with your main speakers, but it’s not a deal-breaker.
The GoldenEar SuperSub X measures 325×356×335mm and weighs 14.1kg. It comes with a five-year warranty on the drivers and passive radiators, and a three-year warranty on the electronics.
In use AnD perForMAnce
The low-frequency nature of the sound produced by subwoofers means that they will always work best when placed in one of only a few specific locations in your listening room. GoldenEar’s Owner’s Manual has some
Using passive radiators to harness the otherwise wasted energy from the rear of the driven cones is very sensible