M&K SOUND V12 SUBWOOFER
M&K’s powerhouse V12 subwoofer is roomfriendly, partner-friendly and sounds great. Who could ask for more?
M&K Sound’s latest subwoofer has a most appropriate model number because just as in the car world you’d expect a vehicle with a V12 engine to have a ‘bit of grunt’, so too does M&K Sound’s V12 have a ‘bit of grunt’… though in this case the ‘grunt’ comes in the form of an extended low-frequency response and a high power output.
THE EQUIPMENT
M&K Sound has never been a company that ‘prettied up’ its subwoofers and the company is obviously sticking with that approach with the V12, because it’s basically just a big black box. But before I go any further, I should say that switching its manufacturing to China has obviously enabled the company to do some ‘prettying-up’ without impacting on the bottom line. All the corners, which were once left sharp-edged at 90 degree angles, are now nicely rounded, for example.
And the speaker grille, which was once fairly industrial-looking, is now a soft black fabric stretched over an MDF frame. If you look at the main photo accompanying this review, which shows the V12 without the grille fitted, you’ll see what I think is an overly-garish and fairly crudely executed ‘V12’ logo below the THX logo that indicates that the M&K Sound V12 is THX-approved. If you agree with me about its appearance, you’ll be happy to learn that when you attach the grille it covers this logo entirely, so all that’s
visible when looking at the front of the subwoofer is the very classy-looking gold-coloured ‘MK’ logo. And if you love the silvery V12 logo, just use the V12 without its grille, so it’s in plain sight.
As for it being a ‘big black box’, the V12 isn’t actually very big at all, measuring only 465×360×400mm (HWD). In fact it’s the largest model in M&K Sound’s range of what it calls its ‘compact’ subwoofers. The company’s largest home subwoofer is the X12, which measures 440×660×460mm (and has two 305mm bass drivers, as against the single 305mm bass driver in the V12).
Although I wrote earlier that the cone diameter of the V12 is 305mm, M&K Sound actually specifies it as ’12-inches’, presumably because the USA is M&K Sound’s single biggest market, and that country still uses the ‘imperial’ measurement system. But in fact, as with all loudspeaker drivers, that measurement doesn’t really mean too much at all, because different manufacturers measure driver diameters using different reference points. In the case of the driver used in the V12, the overall diameter is 310mm, somewhat larger than 305mm, and the spacing between the driver mounting holes is 295mm, somewhat smaller. As regular readers of Australian Hi-Fi Magazine will already know, the only important measurement is the Thiele/Small diameter, as this determines the cone’s effective cone area (Sd), which (along with excursion, or Xmax) dictates how much air will be moved when the cone moves (known as ‘Vd’ for volume displacement. As you’ve probably guessed, Vd=Sd×Xmax. As for the material from which the cone is made, it appears to be paper pulp—the usual choice for large cones, as a large paper cone can be both lighter and more rigid than a cone made from any other material. The dustcap appears to be made from some type of Kevlar-like material, presumably for additional rigidity.
Regular readers might also be surprised to learn that the cabinet of the M&K Sound V12 is not vented, that is, it’s not a bass reflex design. Normally this would mean that M&K Sound is sacrificing some linearity in the frequency response to gain some low end extension and achieve lower distortion than would otherwise be the case. However, because the V12 contains a Class-D amplifier rated at 300-watts (continuous into 4Ω) the company is obviously using this high power to its advantage to tailor the amplifier’s frequency response to compensate for any cabinet losses. Also in-circuit is what M&K Sound refers to as a ‘Headroom Maximizer’ which protects the bass driver from being over-driven.
The controls for the internal Class-D amplifier are located on the back plate. The volume control is rotary, with a smooth action, and ten ‘dots’ are used in place of numerals to indicate volume level. When used in a THX system, the volume must be set at a specific level, so if you turn the volume control completely counter clockwise, you’ll hear (and feel) a ‘click’ that selects the correct level for THX operation. The crossover control is also rotary, with a smooth rotational action, but it has specific frequency calibrations at 60Hz, 80Hz, 110Hz, and 150Hz plus a THX calibration at the extreme clockwise position (but no ‘click’). The phase control is also rotary, so you can adjust phase response smoothly between 0° and 180° degrees, which is rather nicer than the usual two-way phase switch, which offers either 0° or 180° with nothing in-between.
There are two power switches: a main 240V switch and then a three-way toggle switch that allows you to switch between ‘off’, ‘auto’ and ‘on’. The automatic switch puts the V12 into signal-sensing mode, where it will switch on automatically when it detects a music signal and automatically switch to standby after it’s sensed that no music is playing. Setting the switch to ‘on’ forces the subwoofer to stay on 24/7. A multi-colour status LED glows red when the subwoofer is powered-up but either manually switched off or in standby mode, but then changes to glow green when it’s actually operating or out of standby mode.
The M&K Sound V12 offers only line-level inputs (via gold-plated RCA terminals).
Also in-circuit is what M&K Sound refers to as a ‘Headroom Maximizer’, which protects the bass driver from being over-driven.
There are no speaker-level inputs. It also offers line-level outputs, but these are simply looped from the input to allow easy daisy-chaining if you use multiple subwoofers, so the output signal is full-range, and not filtered in any way. Using multiple subwoofers is always best practise, since a single subwoofer will rarely energise a room uniformly, because the size of the rooms in normal homes makes bass propagation problematic.
In Use and Listening Sessions
If you are going to use just a single subwoofer, it’s absolutely crucial that you place it in a position in your room where it will provide the correct balance of sound at the listening position. You can find full details of how to do that at www.tinyurl.com/subwoofe rplacement Be careful moving the subwoofer around because M&K Sound does not supply rubber feet, nor is the base socketed for spikes. You can buy rubber feet at any hardware store, but it’s strange they’re not included. It’s also absolutely essential that you correctly adjust the volume, phase and crossover controls to get a seamless transition to your main speakers. You can find full details of how to do that here: www.tinyurl.com/subwoofer-calibration
My initial listening session didn’t go so well because when I started adjusting the volume, phase and crossover controls, using the procedure described in the link above, I heard a curious whistling sound from the subwoofer. I traced this sound to the rear of the subwoofer, where I found four small holes in the amplifier plate, from which screws had obviously been removed and not replaced. It turned out a previous reviewer had been investigating the insides of the sub and failed to completely re-install the plate. After local distributor Qualifi express-posted replacement screws and I’d fitted them (which took about three minutes) the whistling stopped and I was able to correctly set all the controls for the correct transition to my main floor-standing loudspeakers… which turned out to be the 60Hz (minimum) setting of the crossover control.
Bach is by far and away my favourite composer, and I always like to start subwoofer evaluations with at least one Bach organ work, and this time it was the turn of his spritely ‘Gigue’ Fugue in G Major (BWV 577) even though this isn’t quite as thunderous in the bass department as the two I play more regularly in listening sessions (Toccata and Fugue in D Minor, and Passacaglia in C Minor). It is, however, a lovely work, and a goodly assortment of 16-foot pipes make an appearance in the work’s finale. Importantly, being a gigue, it demonstrated to me how nimble the M&K Sound V12 could be. I heard instant response to both keyboard and pedals, and no unwanted overhang whatsoever. This is not a sluggish sub! When the pedals did come in at the end, the depth and quality of the bass was impressive. The sound was also a little more ‘pure’ than a bass reflex subwoofer, presumably from the reduction in distortion, but also perhaps because there’s only a single source of sound (the woofer) rather than two (woofer and port).
Of course you don’t have to be a pipe organ aficionado to benefit from the extended bass afforded by adding a subwoofer to your system. All the lower notes of the larger orchestral instruments will be improved by using a subwoofer (percussion, harp, double-bass, cello, and so forth) and when playing rock, jazz and other popular genres, drums, bass guitar, electric guitar, and all keyboards will also benefit. One classic lowbass demonstration I always enjoy is using a subwoofer in conjunction with is Pink Floyd’s ‘Dark Side of the Moon’, where the ‘heart’ on Speak To Me/Breathe beats at a frequency of 27Hz. And if you’re looking for some low bass while at a hi-fi show, eternal show favourite ‘Famous Blue Raincoat’ should be in every demonstrator’s playlist, and it gets down to 35Hz on Joan of Arc. The M&K proved adept at delivering the low bass on all the tracks on both albums, with very clean reproduction, splendid clarity and no unwanted overtones.
Since few people—other than audiophiles—own large, floor-standing speakers any more, I also evaluated the M&K Sound V12 with a small pair of bookshelf loudspeakers, again using the calibration procedure out- lined at www.tinyurl.com/subwoofer-calibration This time I found that the setting that gave the best transition between the V12 and the main front speakers was with the calibration control set about midway between the 80Hz and 110Hz positions. The fact that I was using smaller main speakers meant the V12 had to do a whole lot more work, reproducing far more of the low-frequency spectrum, but I still found its performance exceptionally good. The level of the bass was satisfyingly linear and the sound was so clean that I never had any trouble differentiating between adjacent notes when listening to electric bass or double-bass, plus pitch was instantaneously detectable, even for plucked strings. In other words, excellent performance.
Conclusion
It’s quite rare to find a sealed subwoofer at this price-point and equally rare to find a sealed subwoofer that’s such a room-friendly (and partner-friendly!) size. And, as you’ve no doubt gathered by now, it delivers outstanding low-frequency performance. So, if you’re in the market for a subwoofer with all these characteristics, M&K Sound’s V12 would be an excellent choice. Gary Williams
Adept at delivering the low bass on all the tracks on both albums, with very clean reproduction, splendid clarity and no unwanted overtones
Readers interested in a full technical appraisal of the performance of the M&K Sound V12 Powered Subwoofer should continue on and read the LABORATORY REPORT published on page 114.