ATOHM’s engineers have redefined every step of the musical signal chain to deliver peak performance at all power levels.

Explore the technologies X-GUARD™ / U-GUARD™ / T-GUARD™ / X-TEND™ & CSC™


The X-GUARD™ processing overcomes the drawbacks of the classic subsonic filter (or high-pass filter) conventionally used in all bass reflex subwoofer enclosures. The DSP continuously controls the amplitude of the input signal and its parameters (including frequencies).

X-GUARD™ ensures that the speaker's excursion never exceeds an absolute limit (risk of very high distortion and damage). Unlike the traditional subsonic (or high-pass) filter, X-GUARD™ preserves the integrity of the signal, its phase, and does not induce group delay. This technology delivers pure and deep bass of exceptional naturalness. The extreme low end is more faithful, the integration with the main speakers is more cohesive, and the speakers are protected under all circumstances.


The U-GUARD™ processing aims to reduce the formation of square wave signals (clipping distortion) when the device reaches its maximum output level. The DSP continuously measures the amplitude of audio signals. This amplitude is limited to prevent the power stages from clipping.

Traditional analog circuits, often referred to as "soft clipping," produce a softer clipping than a square wave signal.

U-GUARD™ goes further by maintaining a signal shape that is closer to the original and more pleasing to the ear. It also contributes to the protection of the power stages and speakers in extreme cases. This processing is also applied to the low-level outputs to prevent any saturation on the XLR outputs.


During listening sessions at very high sound levels, the involved power can lead to a temperature rise in the voice coils of the speakers (which can exceed 200°C), resulting in a loss of efficiency in the speakers or subwoofer enclosures. This reduction in efficiency is also known as "thermal compression."

Correspondingly, the use of amplifier power stages at very high levels leads to an increase in their temperature.

The T-GUARD™ processing manages the thermal parameters of the power stages in real time, as well as those of the voice coils of the connected speakers or subwoofers, according to the chosen setup. It eliminates certain situations where the device and/or speakers are used inappropriately.


The speakers and their bass reflex (BR) load create a system whose acoustic response is equivalent to that of a high-pass filter. The X-TEND™ processing is based on an extremely precise understanding of this "filter" and all associated electro-acoustic parameters. By conditioning the electrical signal relative to this model, this processing extends the response in the sub-bass (amplitude) while reducing group delay (improvement of impulse response and phase response).

The extension of the response into the extreme low end leads to greater excursions of the speakers. X-TEND™ works in conjunction with X-GUARD™ to maximize the speakers' potential without ever exceeding their limits.


The "Cinema Screen Compensation" technology (active only in speaker mode) modifies the frequency response above 1KHz of speakers placed behind a cinema screen to compensate for the screen's absorption.

Projection screen fabrics are made of materials optimized for image contrast. Depending on their nature, they can more or less reflect and absorb high-frequency sounds. When a loudspeaker is placed behind a screen, its frequency response curve shows attenuation (absorption) as well as anomalies (reflections) in the higher spectrum (typically starting from 1 KHz).

The attenuation is related to the damping and energy absorption by the screen. This attenuation can be compensated to a certain extent by electronic correction.



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