Beethoven or Bartok - which one hums best?

Can the average concert goer be coaxed to broaden his musical tastes beyond the familiar strains of Bach, Beethoven, and Brahms? Consider the comments of some conductors at a recent American Symphony Conductors League meeting here. The issue of how much unfamiliar music should work its way into the average concert program was a key topic in seminars and informal sessions.

''You've got to romance (the audience) - you're selling McDonald's,'' insists Peter Kermani, the lively and enthusiastic president of the Albany (N.Y.) Symphony Orchestra, a national leader over the last six years in putting unfamiliar music on concert programs.

''There should always be a certain amount of tension on the rubber band, but you can't afford to break it,'' says William Wilsen, music director of the Peoria (Ill.) Symphony Orchestra. He recalls that after performing one work which he knew would ''stretch the tolerance'' of his audience last season, the degree of ''outrage'' was enough to make him cancel an atonal Schonberg piece on the next program. ''You have to occasionally pull back,''he says.

''Not all conductors are fascinated by the new and exotic, and I think conductors are best doing the things they want to do,'' says Charles Ansbacher, music director of the Colorado Springs (Colo.) Symphony Orchestra.

Many conductors have long insisted that bold programming of contemporary music can easily trigger a barrage of criticism and canceled subscriptions.

Yet despite a general reluctance to program the new and less familiar, there are growing signs that some conductors at least are willing to risk and accept the consequences. The resounding success last month of ''Horizons 83,'' the New York Philharmonic's festival of music composed since 1969, is expected to encourage even more conductors to follow suit.

Those who take the plunge say the secret lies in how well the works are performed, how balanced each program is, and what care is taken to nurture the audience's respect for and appreciation of less familiar works.

During the coming subscription season in Albany, some 60 percent of the music offered by the Albany Symphony will be contemporary or American or both. Manager Susan Bush, who admits she occasionally gets irate letters and sometimes responds in kind, says few if any subscribers have been lost following the symphony board's bid for an emphasis on performing American symphonic works.

To pave the way for a warmer reception from Albany audiences, the year's program notes are mailed to subscribers in advance of each series. In addition, visiting composers are often interviewed by the local media and speak at club meetings and schools. Noon concert previews are offered a few days in advance of each subscription program.

Like most other conductors who have tried to introduce audiences to the new and unfamiliar, Mr. Wilsen of Peoria insists that it is often the performance which determines how well such music goes over. ''You just have to keep trying to find good music and play it as well as you can,'' he says.

''I feel very comfortable playing 20th-century music and older music that has never been given exposure,'' says Bogidar Avramov, music director of the Beverly Hills (Calif.) Symphony Orchestra. ''Most conductors are old-fashioned - they limit themselves to old war horses like Tchaikovsky's Fifth and Sixth.''

But other music directors, like Mr. Ansbacher in Colorado Springs, insist that successful programming must be tailored to the individual audience and orchestra.

''We put our highest priority on presenting classical music to the broadest possible audience,'' says Ansbacher, whose orchestra has one of the highest concert attendance rates per capita in the United States. ''We've had people who withdraw their support when they hear too much Stravinsky or Bartok. . . . We choose any serious contemporary music we do very judiciously.''