Launched at the ABTT Theatre Show 2006 is Opus Audio Technologies new sub-bass speaker, the UB224. The reflex loaded cabinet consists of two 24" drivers giving an acoustically flat frequency response from 120Hz down to 23Hz.

The National Theatre has already taken delivery of two UB224s for use in the Olivier Theatre. Installed by Opus distributor, Loh Humm Audio, they have replaced two ElectroVoice EV30W speakers that formed part of the original installation from the 1970s.

The theatre's sound department use the Opus ultra-sub to give huge sound effects an 'air-moving' presence. The speakers provide almost a two-octave extension to the main speaker system whilst the very even frequency response ensures that they are able to move the air without rattling the building.

One Opus high definition HD2500/2500 amplifier powers each cabinet with an XS134 crossover set to 80Hz.