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The INFRASUB-18 is a self powered sub woofer system employing a direct radiating 18” cone loudspeak-
er in a sealed enclosure, and a 400 watt power amplifier mounted to an aluminum plate on the back of the
enclosure. The circuitry also includes an INFRA dual integrator providing a flat acoustical response down to
8 Hertz, and Left, Center, and Right channel line level inputs and hi-pass filtered outputs.
Infra Description
The reason that the INFRA type subwoofers sound dramatically better than the others is because of their su-
perior time domain performance. The INFRA subwoofer maintains the bass energy in a tight packet, aligned
with the upper range signal, providing a seamless musical connection with the main loudspeakers. This is
achieved by making the system have a very wide, very flat frequency domain response.
The INFRA driver is operated below resonance and flattened with an electrical boosting circuit, the INFRA
dual integrator. Below resonance the INFRA system exhibits predictable, uniform response and reproduces
each note with the same emphasis, reducing the influence of the resonances found in conventional above
resonance bass systems. In addition, the use of a low pass filter is eliminated (and with it the associated
long variable delay) and replaced with the INFRA dual integrator and its short uniform delay.
Upon close listening it is clear that the impression of power and impact is greater with an INFRA system
when compared to conventional bass systems. This is true even when the two systems will measure the
exact same SPL on a calibrated dB meter. The superior transient response of the INFRA subwoofer provides
a greater body impact than a conventional subwoofer does, at all listening levels.
Objectively the INFRA system exhibits superior frequency and phase response.
Infrasub-18 Description
