The Bose corporation's mission has always been the application of psychoacoustics
to speaker design in order to create as true a representation of live music
The first speaker Bose introduced to reflect this philosophy (pun intended) was the 901 Direct/Reflecting speaker, first introduced in 1968. It had an unorthodox design, small wedge-shaped speakers in a world of large rectangular boxes. The point of the wedge was aimed to the rear, and the two flanking surfaces were covered with small (4-inch) full-range drivers, four to a side. This caused their sound to reflect off of the wall behind the enclosure. The front of the 901 contained a single speaker firing into the room, flanked by tuned ports that used enclosure resonance to create bass frequencies. An electronic equalizer was required to get the speakers to reproduce the full range of sound, and was packaged with and sold as an integral part of the system. The 901 is still being made today, with the current version still using the original design, with some materials and electronics improvements.
It was a highly controversial design when it came out, and was panned by most critics. Needless to say, the general public loved it. Other speakers along the same lines followed, such as the bookshelf-oriented 301, with a couple of tweeters pointed in different directions in one corner, and the relatively orthodox-looking 501, carrying a crown of tweeters pointed in a direct/reflecting array. There is even a pro division that provides speakers to venues. The Bose 801 professional speaker is simply a 901 turned around in a rugged case, with the multiple drivers firing forward.
The biggest advance after the introduction of the 901 was the implementation of acoustic waveguide technology into the Bose speaker line. This enabled Bose speakers to get even smaller while still delivering powerful bass. This development allowed Bose to do what many speaker companies tried and failed to do, sell a satellite/subwoofer speaker set to the mass market. By separating the woofer from the speaker and placing it into a separate cabinet (Bose called it acoustimass technology), the tweeter and midrange (in Bose's case, a pair of pivoting "mid-tweet" speakers) enclosure could be made much smaller. Since bass is omnidirectional (the human ear can't really tell where bass is coming from), only the satellites need to be placed at the traditional stereo locations. This technology is also embodied in the Bose Lifestyle systems, integrated audio/video systems. It is also behind the Bose Wave stereo, a tabletop radio with surprisingly good bass response, due to its internal bass waveguide.
Other significant psychoacoustic developments from Bose are noise-cancelling headphone technology, and Auditioner audio demonstrator technology, which enables designers to hear the acoustics of a room design before actually building it.