Die-hard car hifi fans know: A good subwoofer in the car is a must-have, otherwise the whole system is not really fun. However, due to their basket or cone construction, good subwoofers usually have very large installation depths and often cannot be installed in the desired installation locations. This problem can now be solved with the. HiFonics ZEUS STREET ZST. Subwoofers in flat construction. Thanks to their low installation depths of only 8 or 9 cm, these problem solvers can be installed anywhere where conventional subwoofers are simply too deep. Conventionally constructed subwoofers have a deeply shaped cone, which keeps it in good shape, but unfortunately has a significant negative impact on the installation depth. If you want to reduce the installation depth, such cones are out of the question and you have to use shallower versions. However, if these were built from conventional materials like paper or plastic, these flat subwoofers would not sound good. Therefore, the cones of the. Series are made of an extremely hard glasss fiber carbon composite material. This is the only way to ensure that with high bass excursions, the air is cleanly compressed and without distortion. Also the drivers with large magnets and 50 mm voice coils, which allow an X-Max of up to 15 mm (+/-), are also not common in the class. The 20 cm Sub ZST8 can optimally exploit its potential in a closed housing volume of 10-15 liters, the ZST10 should be used from 20-30 liters. Both subwoofers also play very well in bass reflex tuning, which requires a little more volume, but then plays even more powerfully. Dual Magnet Motor with 2 x 22,5 Oz. 50 mm Dual Voice Coil with X-Max. Composite glass Fiber Carbon Cone. Blue Magnet Rubber Boot. Sturdy Slim Construction Steel Basket.