Bag End Infrasub:
What is Infrasub Technology? Infrasub is Bag End's second generation dual in tegrator bass extension technology. Utilizing Surface Mount Technology, the Infrasub technology provides improvements over earlier dual integrators through modern manufacturing. The extended low frequency approach insures that the lowest 3 octaves of the audio and sensory spectrum are reproduced acoustically in the same time and frequency relationship as the electrical input to the system.
A fundamentally new approach to low frequency reproduction, the INFRA employs electronic compensation to the uniform response that a sealed box loudspeaker system exhibits below its resonance frequency. The resultant frequency response can be extended well below the audible range while at the same time greatly reducing the influence of the system resonance. An INFRA system reproduces each note with precision and uniformity while maintaining a flat frequency and phase response, eliminating the tendency to emphasize the notes around resonance as in conventional bass systems. The enhanced INFRA dual integrator provides both a very flat response below resonance and the high frequency roll-off above resonance, for crossover to the midrange driver, without the use of conventional low pass filters and the delay typically introduced by them. An inherent bonus of the process requires the enclosures to be small. For example, a double 10-inch INFRA system measures only 13" x 22" x 13" (1.5 cu.ft.).http://www.bagend.com/bagend/what_is_infra.htm