Five-Band HOPs

Extending the four-way Huygens Array of §4.5 to five bands, and enforcing octave-band design all the way down yields a five-band Huygens Octave Panel for our consideration.

Figure 13 shows the driver outlines for two five-octave HOPs side by side. Each panel is about half a meter wide, so a 4m wall needs 8 HOPs.

Figure: Two modular five-octave Huygens arrays using the smallest three driver diameters of Fig.11, plus two more octave-band extensions downward. Speaker diameters 3, 6, 12, 24, and 48 cm. Thirty-one channels per panel = 1+2+4+8+16. Channel 32 can be used for a subwoofer. Nominal panel width is 1/2 meter, so 1 meter for the pair.

The top three rows use drivers of the same sizes used in the Kenwood JL-840W four-way speakers (3, 6, and 12 cm), while the fourth row is reduced to 24 cm (down from 30 cm) in order to continue the octave divisions, and a fifth row is added employing 48 cm (19 in) drivers. Fifteen inch speakers are very common, and could be used as a compromise for the bottom row, and subwoofer drivers of diameter 18 and 20 inches appear to be available, but probably quite expensive to use in an array system.³⁰