The other 'Thunder' I call 'Infra-Bass Thunder' might be capable of Infra-Bdass. I saw the patent years ago for the Graham Holliman Velocity-Coupled Infra-bass speaker and have finally figured out how to stuff a Infra-Bass speaker into a WO32 (Wicked One 32) (Use a smaller driver for one thing, the VD-8 is an eight inch sub.) Now that I kook at the pictures I see that it is old
Then remove the 'velocity enhancement' so that the sound wave isn't compressed and decompressed with a traffic jam of air as it compresses and decompresses. THis might be okay with a ten ingh
driver from 1977 with an Xmax of 1/4 inch or something, but the modern SKAR VD-8 is capable of infra-bass without velocity enhancement and instead of short compound tapered waveguides I have a full-on horn. Said horn is longer than the WO32, but I forgot the real length unless this from my note pad is it.... it Might be 7.784166666666667 ft for the Infra-Bass Thunder. Here is the PDF of the Graham Holliman Velocity-coupled Infra-bass Speaker from 1978.
PDF IMAGEhttps://patentimages.storage.googleapis.com/7d/43/05/8700aabd258b78/GB2037534A.p...