Rather than developing a product merely to achieve a beautiful design (which often does not guarantee a high quality reproduced sound) or to follow some production efficiency criteria, the X-Treme designers created the High Power Subwoofers only taking into account the functionality of these products and their final application: reproducing ultra-low frequencies with unparalleled efficiency and performance in the professional audio sector, in the case of both indoor and outdoor great musical events.
Perfect compensation of the masses and volumes, together with reinforcements inside the cabinet, completely eliminates vibrations and maintains the subwoofer characteristics unchanged over time.
The SPL peak is reached at 80 Hz, the volume of air displaced by 15” or 18” components and the structural rigidity of the Canadian birch cabinets make the sound reinforcement always deep, round and diffused.
To sum up: an incisive and long- lasting “big punch”.

Cardiodid Subwoofer
The XTCARDIOID model should be dealt with separately: in fact, it can be defined as a controlled directivity “big punch” cardioid subwoofer.
But what do we mean by the term “cardioid”? In geometry the cardioid is a curve (its name refers to its heart-like shape) and, more accurately, an epicycloid with just one cusp – see the figure.
In the audio sector it means that the cardioid subwoofer polar diagram (that is the angular distribution graph of a speaker system output level at a fixed distance and in the presence of a constantly applied signal) at the working nominal frequency of this subwoofer is of a “heart-shaped” type.
This is achieved by controlling the element components with a power amplifier (for example the XTDT6000F model) and a control processor (such as the XTDP26 model) to manage the delay, in order to combine the response of the two front bi-directional 18” loudspeakers with that of the rear omni-directional one.
The resulting polar diagram looks like a heart, with a peaked anisotropy in the front direction and a minimum response in the rear direction.