LONG recognised as one of the leaders in sound systems, Bose has cemented its reputation at the top with its Acoustic Wave Music System. But it had not been an easy road. It took 14 years and US$15 million in research to come up with a system that delivers sound as true as ''the full emotional impact of a live performance''. By coming up with the Acoustic Wave Music System, Bose technicians put paid to the long-held theory that to reproduce concert-like sound - especially deep bass - bulky speakers or heavy, power-hungry electronics were required. Bose changed that way of thinking and its Acoustic Wave Music System, which was first heard in 1984, continues to grab the attention of those who want top-quality reproduction. That first system, known as the AW-1, contained an AM/FM stereo tuner, a cassette deck, three amplifiers and three small speakers. Only 45 centimetres wide, 26 cm high and 19 cm deep, and weighing seven kilograms, it was designed as a complete self-contained music system. Even with its high quality, which was more attuned to the complicated component systems than to mass-market products, Bose kept things simple; a buyer did not have to be an audiophile to use and appreciate it. It was hard to believe such high-quality sound could pump out from something so compact. The latest of the AW systems has arrived in Hong Kong: the Acoustic Wave Music System Series II (AWMS-II). It is almost identical to the original version except for its colour. The controls remain flush-mounted on the top, while the cassette deck has been replaced by a CD player. Recessed hand grips have been added to the sides of the cabinet. Frequencies above a few hundred hertz are radiated by two 7.5 cm cone drivers, which are at the upper front corners of the moulded plastic cabinet and angled out about 20 degrees. One 10 cm cone supplies the combined bass output for both channels. Each driver has its own dedicated amplifier. What puzzles many audiophiles is how the AWMS-II manages such natural and clear sound with deep base more associated with large, expensive hi-fi component systems. How, for example, does Bose get useful base output down to about 50 Hz from one 10 cm loudspeaker driver with no apparent enclosure? The answer lies in many years and millions of dollars of research: Bose loads the driver front and rear by pipe resonators (or acoustic wave guides as Bose likes to call them), with their open ends exiting at the lower front corners of the cabinet. Such a system produces a uniform response over several octaves (in this case from 50 Hz to 300 Hz). The high efficiency of the dual resonator system enables a small driver and low-power amplifier to generate a useful amount of bass. Bose manages to fit the front and rear pipe resonators, which are 90 cms and 120 cms long, by folding them into a remarkable labyrinth. On the back of the moulded plastic cabinet that houses this technology are a collapsible FM antenna, phono-type jacks for auxiliary input, microphone input and line-level output. The single tone-control slider provides flat response at its centre setting, cutting base or treble as it is moved to either side. The system retails for about US$1,000 (HK$ 7800). The portability of the AWMS-II, without any loss of quality, is a big drawcard. Bose said to exact the same quality of sound that its system could blast out, a user would need a large and expensive component system and contend with the intrinsic problems that went with such systems, including the often-complicated procedures of choice and assembly. Pacific Audio Supplies will give an in-home demonstration or a 14-day trial of the AMWS-II. Since its inception in 1964, Bose has grown to one of the world's top market-share holders. In the 1993 fiscal year, the company sold US$450 million worth of sound systems.