LX-4 MKII
LX-4 MKII is a 2-way Floorstanding loudspeaker with two 5″ bass drivers and a 1″ softdome treble unit.
The LX MKII Series is the latest in a long line of distinguished Mission loudspeakers, joining the multi-award winning speakers from the mid-level QX Series and the flagship ZX Series. LX MKII maintains the Mission trademark ‘Inverted Driver Geometry’ design, which means the path length between the drivers is optimised. Unique at this price-point, this arrangement allows the precision-tuned crossover to yield improved transient attack and astonishing detail.
Perfected over hundreds of hours of critical listening by Mission’s lead acoustic designer, Peter Comeau, Mission LX MKII utilises trickle-down innovations from the revered ZX series. Improvements in the famous Mission DiaDrive bass unit offer superior control of the low-frequency diaphragm while a refined high-frequency performance and a re-engineered cabinet bracing system further help create a loudspeaker system that outperforms its price-class.
Feel the High
High-frequency drive units require extremely consistent parts and manufacturing in order to be selected for a Mission speaker. Given the tiny moving masses involved, one micro-drop extra of high-tech adhesive can destroy the balance of the design, thus affecting sensitivity and frequency response. For the LX MKII Series, Mission has meticulously designed a tweeter with a neodymium magnet, selected for maximum magnetic force in a small space, and a 25mm microfibre dome, chosen for its light weight and consistency in manufacture. It delivers sweetly incisive high frequencies – crisp and detailed with impressive transient attack.
Dishy Drivers
The LX MKII Series features a new version of Mission’s DiaDrive bass/midrange drive unit, where the usual cone and dust cap arrangement is replaced by a seamless curvilinear diaphragm. This is directly driven by a secondary sub-cone connected to the voice coil, improving the efficiency of drive and providing superior control of the smoothly dished diaphragm.
The diaphragm itself is fashioned from an advanced dual-layer fibre formulation, selected for its reduced susceptibility to hygroscopy as well as being very stiff for its mass with excellent self-damping. A high-strength ferrite magnet ensures that the magnetic field is directed precisely within the area of voice coil excursion, enabling an ultra-linear performance and excellent transient response.
Sound with Teeth
One of the critical areas highlighted by the development of Mission’s upmarket QX speakers is the use of ‘comb-tooth’ serrations in the driver surrounds to help scatter interfering reflections from localised surfaces to the bass/mid cones. The LX MKII Series incorporates similar serrations in the main driver surrounds, as well as indentations around the tweeter, adding further finesse to the drive unit outputs and providing a smoother frequency response than the previous generation of LX speakers.
Networking Skills
With minor perturbations in the driver response ironed out, each model’s crossover network has been optimised to take advantage of the improved performance. The LX MKII Series uses a 4th order (24dB per octave acoustic) Linkwitz-Riley network, developed with advanced computer modeling and many hours of listening tests, to knit the drivers together seamlessly. It is particularly notable for its ability to balance excellent off-axis performance with a flatter on-axis result.
Driver Inversion for Musical Immersion
The three standmount models in the range feature DiaDrive units positioned according to Mission’s Inverted Driver Geometry (IDG), with the bass/mid driver sited above the treble unit rather than below to aid time-alignment – a Mission trademark since the 1980s. Placing the bass/mid driver closer to ear level with the treble unit positioned beneath helps to equalise the path lengths from the two drivers’ acoustic centres, so that the sound waves coincide at the listener’s head height.
The two-way LX-4 MKII and LX-5 MKII floorstanders extend IDG to a full D’Appolito array, siting the treble unit between a pair of DiaDrive bass/mid units – one above, one below. The largest model in the range, the LX-6 MKII, is a three-way design, with a dedicated midrange driver positioned above the tweeter, and a pair of bass drivers stationed below.
Boxing Clever
The cabinet is as critical as the drive units and crossover to the overall performance of any loudspeaker system. Designing an effective low-cost box is tricky, as budget dictates that the designer cannot use expensive materials or high mass to create an inert structure.
With the help of 3D Computer-Aided Design, finite element analysis and laser interferometry, coupled with a great deal of experience, a budget cabinet can be designed that delivers better rigidity with lower radiated noise than many would believe achievable at such low material cost. As part of the critical fine-tuning of the new models, judicious placement of extra internal damping fibre inside the rear-ported cabinet has reduced the level of midrange colouration and improved the bass transient attack.
As the Mission LX MKII Series emphatically proves, like many Mission designs before it, budget loudspeakers can truly sing, whilst also being smart, practical and unfussy in terms of positioning.
