Systems List › DIY › GJALLARHORN
This tapped horn DIY design is centered around a large 45x45x24" cabinet form and a single LMS Ultra 5400 driver. The weight with the 80lb driver loaded in is probably near 300lbs. The cabinets are built from 18mm and 12mm Baltic Birch plywood and put together with PL premium construction adhesive and pocket screws. The drivers and access panel mount with 1/4x20 screws and threaded inserts and its finished in Duratex – exactly a gallon and a half on each cabinet. The access panel is purposely large enough to allow for even 21" drivers. Other 18" or 21" drivers may be useable in this cabinet for future testing.
All of the simulating was done in Akabak after realizing that the process worked better designing the physical cabinet and horn fold first and then translating that into Akabak script instead of trying to fold the scripted simulation into the final form factor. This was a many month wash, rinse, repeat process of refinement. The fold of the horn is not elegant by any means and has a number of 90 degree turns and many relatively short sections. It took many days to come up with a fold to fit in this cabinet size with the right length and this is what worked best, but does have compromises.
Inspiration for these was the Danley Sound Th50, the Labsub and the DTS-10. The goal was for something to use in LARGE open spaces like the outdoors and in BIG rooms without a lot of gain and longer than normal listening distances for deep bass reinforcement. In other words outdoors, theaters, Imax installs or high demand venues. The goal was to cover 16-80Hz well in a cabinet that wasn't too gigantic, which is how it ended up at a size similar to a Labsub but slightly wider. That form fits almost perfectly into the space that was available and is still manageable with two strong men.
The driver is able to handle peak inputs of roughly 130v anywhere above 14Hz on a short term basis, which is roughly 4500w into the nominally 4Ω minimum impedance. A pair have been built and are the anchor in a system at a warehouse space which is about 10,000 ft3. This design is not really suited to typical live sound or portable sound reinforcement as it has extension an octave and a half lower than needed which lowers the possible efficiency in the upper bass. It might be useful for high power dubstep or DnB on the other hand, or any other application requiring very high power deep bass in the 16-32Hz octave.