As high-minded composers go, Max Neuhaus is decidedly nonchalant about public reaction to his concerts. Earlier this month at the Como Park Conservatory in St. Paul, Minn, he fiddled with a console, fine-tuned 64 speakers around the botanical garden's great glass dome and then fled the scene as they began to generate stealthily quiet synthesized music round the clock. The concert continues today. It is as permanent as a piece of sculpture, designed to please the visitor who chances to notice something in the air. "Leaving a piece of music to be discovered or not, that's my goal," says Neuhaus, a 40-year-old Texan. "The unexpected can make quite an impact."

He doesn't talk of compositions but of "discoverables," noting, "A lot of people think good sounds come only from Mother Nature or concert halls. I'm proving otherwise." Neuhaus, a leader of the new artistic school of environmental music, has installed his work in such unexpected places as a Berlin swimming pool and a Times Square traffic island. His art is the musical counterpart of Christo's running fences and wrapped cliffs. Like Christo, he's been harassed as well as acclaimed for his pioneering efforts. In 1967 in Buffalo, when Neuhaus was placing short-range transmitters in trees (to broadcast to car radios), police showed up almost nightly to investigate reports of a prowler in the neighborhood.

For its big New Music America festival this month, the city of St. Paul commissioned the Neuhaus discoverable in the conservatory. It took him five months to assemble, at a cost of $43,000. He began by listening to the everyday noise of birdsong and echoing human voices, then wrote a computer program of complementary synthesized tones and rigged 64 small black speakers. Installed among the palms and banana plants, they transmit a subtle pinging that sounds like coins falling variously on glass and hardwood. The effect is serene and meditative. Unlike Muzak, Neuhaus' electronic creations are not obtrusive. "It's all up to the listener," Neuhaus says. To him, the botanical garden makes its own music, and his work merely brings out what's extraordinary about the ordinary.

Another Neuhaus concert warbles night and day from a subway ventilation chamber at 46th Street and Times Square. It cost upwards of $100,000; the Rockefeller Foundation and National Endowment for the Arts paid for the bulk of it.

In 1977, over National Public Radio, Neuhaus invited listeners to phone their local affiliates and whistle aimlessly; the 12,000 "tunes" were orchestrated into a two-hour concert. An earlier Neuhaus series brought reedy underwater sounds to swimmers in 17 pools from Union, N.J. to Mount Pleasant, Mich.

Max's first concerts were family sings around the parlor upright in Beaumont. The son of a chemist father and a physical therapist mother, he played drums in a rock and jazz band as a teenager, then earned bachelor's and master's degrees at the Manhattan School of Music. In white tie and tails, he soloed as a percussionist and toured in ensembles led by conductor Pierre Boulez and composer Karlheinz Stockhausen. He cut an album of music for percussion and electronic tape for Columbia Masterworks. "Then I decided I didn't want to perform only for concertgoers," he says. A year as artist-in-residence among the electronics wizards at the Bell Telephone Labs in Murray Hill, N.J. whetted his ambition to wire the world for sound.

Now Neuhaus is looking for funds to change emergency sirens. He abhors the wailing and explains that pedestrians and drivers on city streets often mistake the direction an ambulance or fire engine is coming from. Officials in New York are interested in his proposal, believing it would help prevent accidents.

Neuhaus lives alone in a drafty loft in downtown Manhattan that was once a jewelry sweatshop. He works six days a week, taking Tuesdays off to browse through secondhand bookstores in search of vintage spy novels, which he collects.

Wherever he goes, sirens remind him of his work in progress. "Each time I start a new project, it seems on the surface to be totally impossible and implausible," Neuhaus says. "I never have any idea what lies before me. I just proceed positively."