DUO Sub-Woofer for mind-blowing lows




The usual speakers are expected to reproduce the full frequency range of a signal. In this compromise particularly the lower frequencies of the music to be played are suffering.

Most of us have knowingly or unknowingly resigned and accepted this "castrated" sound the usual speaker systems are offering. On the other hand, low sounds are relying on large volumes of air and big waves as only massive and big driver membranes, powerful and perfectly controlled, can deliver.



When comparing all loudspeaker concepts available today, WLM is strongly recommending separating and allocating the various frequency levels to adequate drivers, preferably not interfering with one-another and operating on different locations.

The bass frequencies should be taken care by a loudspeaker having a larger membrane and capable of "blowing" big volumes. Also, because of the different propagation of lower (larger) waves, it can be placed almost anywhere in the room (preferably somewhere in front of the listener). 

In a very convincing way the DUO bass speakers are representing together with the WLM main speakers the high level of know-how and expertise of WLM in the building of loudspeakers. This active bass speaker made in the highest standards auf Austrian craftsmanship, with high quality components is coming very close to reproducing music in the most authentic manner. 

The decision to employ natural products has been taken to improve the performance of the speakers, while also helping the environmental cause.

The uncompromising choice for the active operation is proof of WLM's conviction that it is simply the superior technique of today.



The housing, to be free of resonances, has been made of multi-layer real wood (birch) having a wall thickness of 20 mm and strengthend by additional reinforcements. This structure is supporting the heavy and powerful bass drivers with ease. In addition to the added stability, this construction is also enhancing the acoustic properties. The production in the best tradition of Austrian craftsmanship is warrant fort the lasting value and reliable functioning for many years.


Paper membranes and pure wool for dampening are used for acoustic performance and environmental purposes alike.

The quality of the components and of craftsmanship of the DUO series is the same as applied in the WLM main speakers. The choice of wood grains and their surface finish are also identical in both series thus forming a harmonious entity.

In all DUO subs 2 powerful and specially stiff membranes are placed horizontally, 1 above and 1 below in the hexagonal boxes. The 3 models are of identical height and follow the same blue print of construction. However, they have different diameters of the diaphragm: 12'' 15''and 18'', resulting in different cross-sections of the boxes and also in volume of bass to be emitted. In smaller rooms or when only reduced space is available the DUO12 can contribute quite an astonishing bass supplement to that of the main speakers. In large rooms the DUO 18 can show its full bass potential. The DUO 15 is ranging between the 2 others as far as space requirement and bass power is concerned.


Their performance

Only when you expose yourself to the impact of these extremely powerful drivers will you be aware of the shortcomings you have been suffering in the meantime and you will find out to which mind blowing lows a full orchestra or an acoustic bass can reach in your listening room.



Like a building, realistic musical recital needs a solid foundation, a solid bass base, on which the more tender and sensible midths and highs of a signal can rest and extend. Find out for yourself the sovereign and unobtrusive way in which any of the DUOs is doing its job and is thus in an altruistic manner supporting the performance of the main speakers.

The teamwork of these WLM-speakers is best coordinated by the flexible, external WLM filter modul System Control. It splits the frequency range of a signal in highs, midths and lows for separate amplification and is thereafter responsible for their perfectly blended, homogenous and coherent sound image creation by the different drivers, without a gap or disturbing overlap, for the purest and most natural musical enjoyment.