Quality loudspeakers do not come any smaller than this. Following significant research into the optimum design requirements for a satellite speaker it quickly became apparent that any design smaller than the chosen size would lead to the significant sonic impairment of the system. Once this basic design parameter had been established, the Castle design team then concentrated on the design and construction of a cabinet as inert as possible and to the development of excellent drive units for installation in the cabinet. Despite the compact size of the enclosure, Castle's team decided that a 15mm MDF board was the minimum acceptable to achieve the stiffness required. Both the internal and external surfaces of the board are fully veneered to further increase stiffness and long-term rigidity. This fundamental rigidity is then further enhanced by the extensive use of internal bituminous damping. The Castle Compact Satellite uses two new drive units specifically developed for this project. The tweeter is a 19mm (3/4-inch) fabric dome with a neodymium magnet assembly; this unit, despite its small size, has been developed to have a large radiating area, ensuring optimum dispersion characteristics. This design has also been optimised for extended high frequency response and is one of the few tweeters capable of performance up to 40kHz, making it an ideal tweeter for use with DVD-A and SACD source material. The 110mm (41/2-inch) bass-mid unit has been Klippel optimised and features a woven glass fibre material offering good internal damping, smooth response and excellent dynamic capability that is so required in modern AV speakers. The unit also features a four-layer voice coil, offering extended power handling and a magnet assembly featuring a copper cap on the pole for maximum dynamics and an aluminium ring to compensate for induction variances. These last two design items are normally only found in drive units retailing at significantly more than the Castle Compact Satellite. Having successfully designed both the drive units and the cabinets Castle have ensured breathtaking performance by the careful integration of the elements into one complete system. The enclosure is a closed box design, facilitating easy room placement, which has a Q of 0.7 and a fs of 90Hz, The drive units are integrated into the cabinet by way of a fourth order Linkwitz-Riley crossover using both Polypropylene capacitors and balanced resistor technology in the tweeter section. All these combine to produce a speaker with both ease of placement and faithful rendition of any signal fed into them.