Officials at Harvard and the American Broadcasting Company (ABC) yesterday revealed details of an unusual symposium on voter turnout they are co-sponsoring this fall that will bring together President Reagan, former Presidents Carter and Ford, and a host of top government officials, politicians scholars, and journalists.

President Bok and several Harvard professors are scheduled to participate in the two-day Washington conference, which organizers yesterday said would focus on solutions to the drastic nationwide decline in voter participation that has occurred over the past 20 years.

The meeting is believed to be the most extensive gathering ever of scholars, government, and media officials who can suggest and implement reforms in the electoral process, rather than just discuss them, conference organizers said.

"In the past, the problem of a decline in voter participation has been examined mostly in piecemeal fashion," Kevin Gottlieb, Harvard's liason to ABC and the chief conference organizer, said yesterday. Gottlieb and others noted that the last major systematic review of voting procedures took place more than 20 years ago, before the onset of the drastic decline in turnout that reached a level of just more than half of eligible voters in the 1980 general elections.

The conference is expected to attract wide spread national attention, and will be taped and edited for a major documentary that ABC New plans to broadcast sometime next year, organizers said.

Moreover, officials added the event represents the first major collaboration between a media organization and Harvard to arise from a new academic center under the development at the Kennedy School of Government.

The Center for Press, Politics, and Public Policy--to be located in the new K-School wing slated for completion next spring--will regularly sponsor meetings on a variety of topics related to the media's role in affecting citizen participation in government.

The current agreement calls for ABC to pay for and organize the meetings and for Harvard to coordinate the agenda and participants. Organizers would not disclose how much the conference would cost, but noted the extent of provisions being planned for the Sept. 30 to Oct. 1 event.

While about 45 leading political experts. journalism, and government officials will actually participate in the meeting's three scheduled sessions more than 500 prominent representatives of the different fields have been invited to each of two formal dinners connected with the conference.

When they first disclosed plans for the event several months ago, officials had not decided whether to hold the meetings at Harvard or in Washington The nation's capital--and the meeting's headquarters at the Smith sonian Institution--were ultimately selected so that more top politicians could attend or organizers said.

The list of participants, now being finalized includes current and past chairmen of the Democratic and Republican an National Committees; the heads of the Federal Communication Commission and the Federal Election Commission, president of the League of Women Voters top officials of ABC, CBS and NBC News several Congressional leaders from both parties leading political pollsters and scientists and prominent syndicated columnists including David Border and Elizabeth Drew.

Besides participating in at least one of the working sessions, President Bok will host one of the dinners along with Leonard Goldenson, chairman of the board of ABC, Inc. who reportedly holds great interest in the issue of electoral reform. Goldenson first met with K-School officials to discuss the conference during a visit and speech at Harvard last winter.

Other Harvard participants last winter School Dean Graham T. Allison, K. School Associate Professor of Public Policy Gary R. Orren; and Professor of Government Sidney Verba '53 a reknowned authority on voting and demographic patterns.

Because the actual meetings will be devoted to in-depth discussion of voter education the voting process and the media's effect on the campaign process officials said the dinners will serve as the primary forum for broader speeches by the conference's most prominent participants, Reagan Carter and Ford.

President Reagan has not yet decided which of the two dinners he will attend though he has definitely accepted an invitation to speak Gottlieb said adding that Carter and Ford will speak at both dinners.