The most distinctive feature of the BeoLab 9’s design was the “acoustic lens” that surrounded the upward facing tweeter. The action of the acoustic lens is explained in the description of the BeoLab 5 and the same principles, though on a smaller scale, were applied to the design of the BeoLab 9. The BeoLab 9 used 3 drive units, described as a 10” woofer, a 5” midrange and a 0.75” dome tweeter. This made for a nominally 3-way loudspeaker, though given the sizes of the drive units and their crossover points the effect was more akin to a small 2-way loudspeaker working in conjunction with a well-matched subwoofer. This setup can be contrasted with the earlier Uniphase models (e.g. the Beovox S 80.2) to see how the design parameters had changed. As 3-way active design the BeoLab 9 required three separate power amplifiers. B&O demonstrated their ability to for a rational solution from the available technologies by selecting a class-D amplifier (ICE Power to give it its marketing name) for the woofer and two conventional linear class AB amplifiers for the midrange and treble. This was an inspired choice, the bass amplifier could be made very powerful (500W) without having to make the cabinet too big or the heat sinks too obtrusive and the heavy, and the well damped bass driver was largely insensitive to the types of distortion it generated. Meanwhile, the sensitive midrange and tweeter loudspeakers, which at 100W each needed much less power, were fed with a pure signal which only a proper linear amplifier can provide. A hybrid based design was chosen, using a single package whose two channels would normally have been used for left and right in a conventional amplifier. This arrangement was common to many loudspeakers in the BeoLab range. An electronic switch mode power supply was used instead of a conventional mains transformer, bringing with it the advantages of high power density, low cost, light weight and the elimination of the need to adjust the line voltage for different markets. The last item was the only one of technical merit, although one can see how the other attributes would be attractive to the manufacturer. B&O were clearly conscious of the poor reliability record of their earlier active loudspeaker models when designing the BeoLab 9. Elaborate protection systems were built in that protected the loudspeaker units against both overdriving and overheating. This was clearly wise given the BeoLab 9’s potential power output. Connections to the audio system were made by Powerlink cables. Older or non-B&O equipment could be made using special cables terminated in a variety of standard type plugs. A switch on the loudspeakers set the input to “line” mode to allow these cables to operate correctly. The traditional “free/wall/corner” equalising switch was also present. The BeoLab 9 lacked the complex digital input, digital signal processing and automatic calibration functions of the BeoLab 5 but then it was also considerably cheaper. High quality was assured as the available resources were directed towards the essential parts of an active loudspeaker rather than clever gimmicks that were unlikely to be used much. Well-designed, well-thought-out and well-made, the BeoLab 9 really did deserve success. Truly excellent speakers, a high-quality speaker set. High-end level. Class D ICE POWER AMPLIFIER. To really enjoy music at home, every tone from the deepest bass tone to the highest musical note are reproduced very clearly by these speakers. Wherever you are sitting or standing. Only then can music move you to tears or make you burst out laughing. The true music lover will recognise its sublime quality from the first note onwards. Due to the Acoustic Lens Technology, you will not miss a note. The sound is of the same quality throughout the room, whatever you are doing, wherever you are. The acoustic lens is mounted on seat height so you can embrace the music. The Acoustic Lens Technology ensures sound waves spread evenly. Built-in amplifiers and subwoofer. The speaker can be connected to all Bang & Olufsen BeoSound BeoMaster BeoVision audio, vision and link systems, and also to non-B&O systems. It can be used via line to wirelessly stream via Bluetooth or Wi-Fi internet from tablet of phone. It can also be connected to all TVs for a sublime sound experience. ICE POWER class D amplifiers 700 watts per speaker. SPECIFICATIONS: Power consumption 65W (IEC60065) 25W typical < 0.4W in standby Power amplifier, bass 500W, class D ICEpower Power amplifier, midrange 100W, class AB Power amplifier, treble 100W, class AB Long-term maximum output power per amplifier Bass: 400W/4ohm Midrange: 100W/6ohm Tweeter: 100W/8ohm Effective frequency range 28-29,000 Hz Crossover frequency 180/2000 Hz Cabinet principle Closed box. Net volume, bass 18 litres Net volume, midrange 4 litres Thermal protection of all drivers. ABL system protects the bass unit against mechanical damage. Power supply Automatic voltage adaptation 100-120Vac or 190-240Vac