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  2008 Updates
  System Design

Elimination of Passive Crossover

The Integris Active 300B has no passive crossover components between the power amplifiers and the loudspeaker drive units. Instead, all are direct connected and the crossover functions are created in the low-level amplification stage. This difference from conventional loudspeakers results in several advantages.

Firstly, the more a passive crossover attenuates signals, the more it inhibits good performance. Conventional multiway passive crossover design involves balancing a design to its lowest sensitivity driver usually the woofer. Extra midrange and tweeter sensitivity - hence much of the available amplifier power - is wasted. An active loudspeaker, without passive crossovers, uses all of its drive units' available sensitivity and 100% of the power that is sent to the drivers. Less powerful amplifiers are demanded in this type of application thus permitting the consideration of the 300B single-ended-triode configuration as used in the Integris.

Secondly, passive crossovers, especially in three-way designs similar to the Integris, consist of large complex filters that present difficult and wide-ranging impedance loads that can challenge many amplifiers. Complex passive crossovers also create a degree of separation or decoupling between the amplifier and driver in terms of control. Across much of the bandwidth, the amplifier is interacting with the crossover far more than with the loudspeaker's drive units. Without reactive crossover components, the largely resistive loads of the drivers are optimal for signal transfer and stable amplifier performance. The Integris 300B SET sections are able to do their job without any difficulty in the crossoverless design.

Finally, large passive crossover components are typically quite inferior to the small precision components used in the low-level amplification stages of the Integris. The Integris system's filters, located before the power amplifier sections of the system, are built strictly around small precision custom-made Cardas polypropylene film capacitors and precision metal-film resistors. No inductors are used at all in the signal filters this eliminates the mutual electromagnetic coupling effects that often occur within passive loudspeaker crossovers. Also, being situated in the amplifier and being of much smaller physical size, the negative consequences of vibration are significantly reduced in comparison to passive loudspeaker crossovers.

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