Although Harman rates the Infinity Primus P363 as 8-ohm speakers, what I measured tells a much different story. These are clearly 4-ohm speakers. They appear to be tuned just below 50Hz, but the saddle points are quite asymmetric. This indicates a system tuning too low for the available box size needed to produce a more optimal response. The 4 ohm dip between 100Hz to 200Hz is a bit concerning for those wanting to use these speakers with budget A/V receivers. Even if bass managed, these speakers can present a rather strenuous load if the amplifiers in the A/V receiver don’t take kindly to 4-ohm loads. I found that Infinity employed a 4-ohm tweeter as evident by the impedance dip above 10kHz. I believe they did this in attempt to increase speaker sensitivity.
