Frequency: F3= 37Hz -3dB with 1 box, 33Hz -3dB with 4 boxes and 30Hz -3dB with 8 boxes.
Efficiency: 1box 1w1m 2Pi (2.83volts) = 102db,4 boxes 1w/1m 2Pi (1.41volts) = 106.5dB
Enclosure Type: Tapped Horn
Recommended driver: LF18N401 Spec Sheet , Kappalite-3015lf
Artwork by Job63 on http://hornplans.free.fr: