BAG END Loudspeaker Systems is unveiled a new generation of bass signal processors, called INFRA, at the 2003 AES Show, Oct. 10-13 in New York City. The INFRA processor series includes the INFRA-M and INFRA-M2.

“The new INFRA signal processors represent an improvement in reliability and manufacturing from our previous signal processors,” said James P. Wischmeyer, president of the Barrington, IL, manufacturer of loudspeaker systems. “When the dual integrator technology was first introduced by BAG END ten years ago, we called it a ‘development of milestone proportions,’ and said it would change the way we think about bass sound reinforcement, and I believe that holds true.” Simply stated, the technology operates a subwoofer below resonance without the use of low pass filters, thus eliminating filter delay, impedance bumps and other irregularities.”

In the INFRA technology, the electrical signal goes through the INFRA electronics before the power amplifier, as it would with a conventional electronic crossover. Inside the INFRA electronics, a slope is applied to the signal by the use of dual integrators lifting the low frequencies by 12 dB per octave.

The INFRA loudspeaker is placed in a small enclosure providing a relatively high system resonance for a subwoofer. The system's response without the INFRA electronic drive will rise at 12 dB per octave up to its resonance frequency and then flatten out until the woofer reaches its upper limit. When INFRA drive is applied, the 12 dB per octave roll-off of the cabinet combines with the 12 dB per octave lift of the electronics to form a flat frequency response down to the lowest point set on the INFRA electronics, as low at 8 Hz. Above resonance, the loudspeaker would normally respond flat up into the midrange. With INFRA drive, the dual integrators roll-off at 12 dB per octave from the system resonance or the point where the speaker would normally run out flat.

There are no low pass filters in INFRA technology. Therefore, there is no filter delay. Below resonance the impedance, cone excursion, and dampening factor are uniform and predictable. Thus, the reaction time, controllability, and the ultimate fidelity of the loudspeaker is dramatically improved. The spatial offset between the INFRA system and the upper range loudspeakers is minimized, providing a seamless match that is truly remarkable. "The result is a conveniently sized subwoofer with a highly musical and precise extended low frequency capability," Wischmeyer concluded. "To boil it all down to one concise phrase, INFRA technology makes a bass system simpler, smaller, and - at the same time - makes it sound better."