THE highly acclaimed Howard University Jazz Ensemble--Lionel Hampton called it his favorite college band--is going to have it rough for the next four weeks. Well, not too rough. The ensemble will be performing in five cities in Central America and the Caribbean: Port-of-Spain (Trinidad and Tobago), Port-au-Prince (Haiti), Bogota' (Colombia), Tegucigalpa (Honduras) and Guatemala City (Guatemala). They flew out of town yesterday.

This won't be the first overseas trip for the group: in 1976, it spent two weeks in Romania, cosponsored by Howard and Friendship Ambassadors, a New York-based nonprofit group that, according to HUJE founder and director Fred Irby III, "tries to promote harmony and friendship with East European countries through music." And in 1978, the group performed in St. Thomas and St. Croix, cosponsored by Howard's Alumni Association and the University of the Virgin Islands. "It was in February," Irby recalls wistfully, "and when we left Washington, there were five inches of snow on the ground."

The current trip is being sponsored by the United States Information Agency as part of its Arts America program, which sends 40 performing groups and fine arts exhibitions abroad each year (mostly in response to specific requests from overseas embassies). At least four other collegiate ensembles submitted applications and tapes, Irby says, "and we were the unanimous choice because of past accomplishments. They said our presentation was much better: we were the only ones that sent in records--the others sent in tapes. We also sent in an hour-long color film about us, produced last year by our television station, WHMM. It was very professionally done."

Professional media backup is just one of the strong suits that have made Howard's Jazz Studies Program one of the best in the country. For instance, the HUJE has released an album every year since 1976. According to Irby, the idea actually came about during the first trip to Romania. "We used to sit around and talk about it and at that time the students decided they wanted to record an LP. What they really wanted to do was find out how to put an album together and we felt that the best way was just to do it."

"We did everything piecemeal. Some students were assigned to find out how much it would cost to rent a studio. Some were in charge of the jacket, others of the pressing. It was a class project . . . and it was one big, gigantic headache," he adds. "After that we decided we would go with an educational company that specializes in producing collegiate jazz albums, Mark Records of Clarence, New York, and that's who we've used ever since."

As the jazz studies program started to develop--it now offers a master's degree--it became a bit like the collegiate football factories whose reputations attract top-notch players. "We became known as a group that does a recording every year and travels," Irby says. "As a result, some kids coming out of high school who wanted to get experience in these things automatically chose Howard. The record is part of the curriculum; its costs are part of the budget."

The albums have elicited widespread praise, much of it in the form of surprise that it's undergraduate students doing the playing. "We're known in places that we've never been, like the West Coast, because our records have been played on radio stations out there. And the Voice of America plays us; we get orders from around the world."

Although the jazz studies program is fairly new (it was started in 1970 by trumpeter Donald Byrd and is now headed by Arthur Dawkins), Irby points out that "Howard has always had an excellent music department from way back." Among its best known graduates: Roberta Flack, Donny Hathaway, Andrew White, opera star Jessye Norman, Baltimore Symphony trumpeter Langston Fitzgerald, producer Freddie Peren, Tawatha Agee, who recently had a No. 1 hit with "Juicy Fruit," and Angela Winbush of Rene and Angela (she used to be a part of the Jazz Ensemble). Another recent ensemble graduate, Natalie Denise Jackson, is currently singing in trumpeter Tom Browne's fusion group, and yet another, Geri Allen, is musical director for the Supremes. "We're stacking them up," Irby says.

That's particularly true of the prestigious annual Down Beat student recording awards, which Howard dominated in 1981 and 1982. In 1981, trumpeter Wallace Roney won the jazz instrumental solo category (he went on to replace Wynton Marsalis in Art Blakey's Jazz Messengers) and last year the award was won by alto saxophonist Roger Woods. "Roger came to Howard because he wanted to go to a school that recorded every year so he could get studio experience," Irby says. Also in 1981, Larry Seals won the blues-pop-rock soloist's award, while Natalie Denise Jackson won the vocal category for "Loving You Has Been an Ecstasy," written by Carroll Vaughn Dashiell Jr. The song became No. 1 on WHUR and got a lot of local play. Other HUJE members received "outstanding performance" citations.

All the winning works were from the HUJE records, which mix compositions from students and professors like John Malachi and Reppard Stone. Says Irby: "We try to give the students skills that they can use in the real world. And students can use the recordings as re'sume's when they go out and apply for jobs--it's so professionally recorded and put together. We concentrate on performance, but also on arranging and composition."

Besides his extensive teaching duties, Irby is also a tenured member of the Kennedy Center orchestra and musical director of the big band Swingworks (which had to cancel some September shows because of the USIA tour--"We'll be performing when I get back"). He's particularly proud of his players and says "they keep in touch. When they're in town, they drop in to see what the group's up to. They know when we rehearse--it's been the same place, the same hours for the last nine years."