Revolution in American popular music

At the moment there is room for sounds of every sort in rock and pop music. It is benefiting a great deal from a recent explosion of musical methods and manners, and from a recent willingness to abandon old boundary lines.

The Kitchen, an experimental showplace here, has presented avant-garde variety shows, giving a cross section of current fare, and the most striking aspect of each program has been its unpredictability. A versatile talent like Ned Sublette might sing a traditional folk song, with all the energy and conviction of an Eric von Schmidt, then be followed by an established rock star like Todd Rundgren, singing a war-protest song with an acoustic guitar. Performing poets like John Giorno and Jim Carroll might share the bill with jazz saxophonist Julius Hemphill and dancer Joanne Robinson.

A ''rap'' group might pop up - like Fab Five Freddy and Friends - spinning a thread of half music, half talk, accompanied by electronic rhythm, and maybe joined by the Rock Steady Crew, whose act veers from dance to acrobatics and back again.

And if it's plain rock you want, with a sophisticated twist, there are such groups as Red Decade, led by Jules Baptiste, and the Love of Life Orchestra, with David van Tieghem, Sublette, Jill Kroesen, and others under the direction of saxophonist Peter Gordon. Or, with a more funky orientation, Oliver Lake and Jump Up, who recently completed a State Department-sponsored tour of Africa.

Unconventional instruments also play a part in recent developments. The performer called Zev works with ''found percussion,'' coaxing fantastic sounds from unlikely objects. Van Tieghem drums on objects other than drums, punctuating his act with sounds as diverse as the whirring of children's toys and the munching of Rice Krispies.

Laurie Anderson uses devices ranging from wooden blocks to walkie-talkies, blending them into an effect that's . . . gently relentless, you might say.

More ''normal'' instruments take on new roles, too. In one of his compositions, trombone player Garrett List alternates blasted brass tones with the sound of his own voice.

More elaborately, the George Lewis Trombone Quartet has played with mutes plugged directly into amplifiers. This has the effect of subtracting and adding sound at the same time. It also illustrates the trend toward finding unusual uses for conventional music equipment (such as the mute) and electronic enhancement.

If there is one theme running through all these sounds, it's energy. That is what unites the rocker whose inspiration comes from classical sources, and the conservatory graduate who's attracted to the perpetual pulse of rock-and-roll.

Other manifestations of ''new music'' are more purely classical in style, and appeal to a more specialized audience. But no one can predict just what the future holds.