THE YEAR IS 1969, the heaviest year on record. A bunch of buddies are sitting around a dorm room, sitting on the floor between two stereo speakers.

"WOW," says one of them about the music - complex, soaring sounds that jump from speaker to speaker, "Pink Floyd is really something."

Now the year is 1973, the time is last night and the place is the Spectrum. On stage, infront of 12,000 people in the shortened Spectrum Theater, is Pink Floyd.

This time, the enthusiastic audience is seated not between two speakers but six sets positioned around the perimeter of the concrete room.

THE MUSIC IS complex, the show business effects boffo, the band as tight as a drum.

Wow, Pink Floyd is still really something.

Back in the late 1960s, Pink Floyd was the forerunner of weird music, which today takes in Yes, Emerson, Lake and Palmer, even the Mahavishnu Orchestra. While other bands were doing four-minute songs, Pink Floyd was putting one number on a side of its records. People were flabbergasted: 20 minutes for one song?

With its experimental, heavily improvisational (within a set framework of course) music, Pink Floyd developed a distinctive stage show.

Last night, the first half of the group's two-and-a-half hour set was a throwback to 1969. There were bass thrums building for minutes, long organ chords held seemingly beyond endurance. Smoke billowed out of vents on the side of the stage, filling the room with artificial fog. Synthesizers emitted howls that rocketed from one speaker cluster to another, circuiting the room. Strobe lights on stage flashed in time to the music. A six-foot tall mirror ball sent lances of light through the smokey room.

The stage was lit by batteries of red, green and blue lights. When the whole arsenal worked at once - strobes, spotlights, smoke, mirror ball - it looked as though the band was floating in a sea of magic tricks.

AFTER THE BREAK, the band played two selections from its new Capital album, the second number being the album's title cut, "Dark Side of the Moon."

This 20-minute spellbinder so encaptured the audience, making such excellent use of the 360 degree sound system (example: a laugh was projected out from stage and circled the room) and the band's great instrumental ability that the group was already off stage when the audience recovered from its revery and started a wild ovation, asking for an encore.

Pink Floyd's music sounds almost melodic today, easy to follow if not quite hummable. Basiclly, the band starts with a basic drum beat, guitar, bass line and then endlessly repeats the basic elements always embelishing them with new heights.

The band is David Gilmour, guitar; Nick Mason , drums; Richard Wright, keyboards and Roger Waters, bass.