We are all familiar with speaker cabinets containing woofers, midrange, and tweeters, etc. Each cabinet can be considered a monaural multiresolution speaker system, typically three-way. Additionally there is often a subwoofer somewhere putting out the deep bass.
The Kenwood JL-840W speaker systems are four-way:23They use four circular drivers having diameters 30, 12, 6, and 3 cm.24 The crossover frequencies are at 2, 5, and 10 kHz, which is at for the speaker driving below crossover, where is wave number in radians per meter, as usual, and is speaker radius.25 The nominal total frequency range of the system is 20-20 kHz, but amplitude drops off in the woofer (30 cm) for wavelengths much greater than the diameter, which must be compensated by extra drive. The super-tweeter, tweeter, and midrange drivers have diameters on the order of one to two wavelengths. The woofer high-end is near that range, but must handle all lower frequencies as well.
We can extend existing -way speaker systems to multiresolution line arrays in a straightforward manner. We use the term Huygens Array (HA) to refer to any collection of drivers used as a spatial imaging array, and in particular, Huygens Octave Panels (HOP) will refer to multiresolution line arrays having octave divisions.26