Active Motion Control is a unique circuit topology developed by Krell specifically for the Master Reference Subwoofer. An instrument grade accelerator, mounted to one of the drivers, relays information about the driver’s position to the Active Motion Control circuit, where it is compared to the musical waveform at the amplifier input stage. Amplifier parameters are then adjusted to ensure that driver motion is faithful to the input signal, and feedback is precisely applied to preserve sonic impact. Krell Active Motion Control allows the Master Reference Subwoofer to achieve complete driver control and deliver
Enclosure
The enclosure is an essential part of any loudspeaker and is particularly significant in subwoofer design. Low frequency energy causes some of the most stable materials to resonate. Enclosure resonance degrades performance and destroys linearity. Krell engineering has attacked these design challenges with a vigorous application of technology,
The enclosure for the Master Reference Subwoofer is made of 1 in. thick, aircraft- aluminum billet. Each of the two driver baffles is a substantive 21/4 in. thick. The subwoofer assembly is held together by 68 machine screws, size 1/4 20 x 1 in. The precision machine finish is black anodized to a
Drivers
The high performance demands of the Master Reference Subwoofer require drivers of exceptional capability. Krell has researched every aspect of driver design and construction to produce remarkable transducers. The Master Reference Subwoofer contains two 15 in. drivers, which have been custom crafted to Krell’s own rigorous specifications. The drivers are mounted at opposite ends of the case, firing outward, away from one another. They are wired in phase: One driver’s motion has the effect of canceling the motion of the other, rendering the enclosure free of operationally induced vibrations.
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