Jerusalem Symphony Orchestra musicians plan to demonstrate this afternoon at the Israel Broadcasting Authority in Jerusalem. But the people they want to impress the most won't be there. The IBA management committee usually meets at IBA headquarters on Monday afternoons, but not this week, according to IBA spokeswoman Linda Bar. Only the television and radio committees will be meeting, she said. The musicians are upset over IBA budget cutbacks that threaten their livelihood and the JSO, the second oldest symphony orchestra in Israel. The IBA has provided NIS 11 million of the JSO's NIS 15m. budget. But it said it intended to slash its contribution to NIS 5m., and even that would be conditional on matching funds from the Culture and Sport Ministry and the Jerusalem Municipality. Contrary to agreements reached between the IBA and the JSO, the IBA has included the JSO in across-the-board budgetary cuts. The decision contradicts an agreement reached earlier this year with the State Comptroller's Office, which stipulated that no changes would be made in the JSO budget without government approval. The blow to the orchestra's funding would have been disastrous under any circumstances, but more so at a time when the orchestra and its musical director, Leon Botstein, were planning its 70th anniversary celebrations. As things stand, they could end on a very sour note. IBA chairman Moshe Gavish has made it clear that the IBA must take drastic cost-cutting measures. But according to JSO director-general Yossi Tal-Gan, cutting the orchestra's budget will not solve the IBA's financial difficulties since the JSO accounts for less than 2 percent of the IBA's expenditures. He said the JSO was operating without a deficit and repaying previous debts. Botstein forfeited his salary to help. He also set up the American Friends of the JSO, through which he has raised significant funding. Botstein said he was appalled that so little was being done to ensure that the JSO remains a national treasure headquartered in the nation's capital. "It is my hope that the Israeli public will override the machinations of rival bureaucratic factions in the government," he said, "and that the Knesset, prime minister and new president will act swiftly to preserve and strengthen this vital and historic institution on the eve of its 70th anniversary and of the 60th anniversary of the State of Israel." Botstein expressed confidence that "wiser heads will prevail and the outcome will be positive, securing the Jerusalem Symphony Orchestra as the major part of Jerusalem's secular culture."