Harman Kardon TC600 Owners Manual - Page 31

The TC Series simultanous bridged mono/stereo satellite operation demonstrates this minimum impedance concept, as these diagrams illustrate: -~ ~ Improper impedance loading Proper impedance loading Len satellite speakers 2-ohm min~mum 2-ohm minimum If the left and right satellite speakers are 2 ohms and operated full-range, the amplifier would see a proper impedance load. However, if a 4 ohm subwoofer is additionally bridged across the left and right channels without a crossover filter, the amplifier will now see 1 ohm per channel in the combined woofer/satellite operating range, thereby eventually triggering the amplifier's protection mode (a 4-ohm bridged load looks like a 2-ohm load per channel to an amplifier). Separating the operating ranges of the satellites and woofer with a passive crossover filter as shown in the above example will provide a proper minimum impedance load of 2 ohms stereo above 8OHzand 4 ohms bridged mono below 80Hz. 30