hd Sub21

The hd Sub21 is a passive high-performance subwoofer equipped with a 21“ neodymium woofer chassis of the latest generation with bass reflex tuning for medium to large sound reinforcement applications. The specially developed loudspeaker chassis, which achieves extremely high sound pressure and resilience thanks to its innovative design, sets new standards in the ratio of size to performance in mobile or permanently installed applications.

Its excellent impulse behavior and fast response are unique for a 21“ subwoofer and make it a universally applicable and linear subwoofer with brutal depth. Compared to the most powerful direct radiator to date, the hd Sub18, the Sub21 is able to generate more than 15 dBSPL more in the low frequency range below 35 Hz and is therefore aimed at users who need pressure and headroom even in the lowest octave. Ports optimized with CFD flow ensure silent operation even at maximum load.

At just under 60 kg, the compact housing is also quite handy. An M20 threaded insert on the top of the housing allows a spacer rod to be accommodated. In addition, four abrasion-resistant rubber feet on the underside and the associated cutouts on top provide for a secure stacking of the same enclosure. The enclosure is made of multiplex wood and provided with a shock and weather-resistant polyurethane coating. The speaker front is protected by a sturdy front grille with internal acoustic foam. Generously dimensioned transport handles are integrated into the side walls. Auf der Rückseite befinden sich Einlassgewinde zur Befestigung von hd SilentWheels, den akustisch entkoppelten 100 mm Rollen, sowie ein versenktes Anschlussfeld mit zwei NL4 Buchsen zum Anschluss über Pin 2+/2- und Weiterleitung des Eingangssignals. It is operated on all Harmonic Design® system amplifiers to ensure reliable and precise bass reproduction.