"Sing the note you hear on the piano . . .

"Open your mouth . . .

"Louder . . .

"Sing 'from' - and slide up as high as you can go . . .

"Louder!"

It was audition time for the D. C. Youth Chorale, the official, citywide chorus of Washington's public schools.

Auditions took place at Ellington School of the Arts, at 35th and R streets NW, the current home of the chorale, at 6 o'clock on a Tuesday night, when most kids are home at dinner.

The man giving the orders in the mellow but authoritative tones was Edward Jackson, chorale director. The performers were a dozen students in grades nine through 12 from schools throughout the District: McKinley, Kramer, Dunbar, Roosevelt, Woodrow Wilson.

For some, auditioning was old hat. Geoffrey Adams, for example, turned on like a light as soon as there was an audience. A junior at McKinley, Adams started singing in church at the age of 4. When he sang his favorite song for the youth chorale staff - "The Sound of Music" - he was putting on a show.

"I sing before other people at school, at church, all the time," said Adams, "I love to entertain."

For others, it was like jumping into a pool for the first time.

"I've never auditioned before," said Luther Jones, 17, a student at Armstrong Adult Education Center. "I was scared."

In an adjoining room, the students, waiting to hear who made the grade, crowded around a piano as Adams hammered away at the top 40.

They soon found there was no need for quavering voices and tightened throats. They all were selected.

In the D. C. Youth Chorale there's room for the rank beginner and the aspiring professional. According to Jackson, everyone gets to participate in some of the approximately 30 performances given each year by the full chorale, its ensembles and soloists.

"The chorus doesn't look for outstanding voices - it looks for accurate voices and clarity of diction," said the director.

The most promising students are offered the chance to take voice lessons free once a week, taught by Jackson and other members of the chorale staff. For models they have such successful chorale graduates as Carmen Balthorp of the Metropolitan Opera and Wilma Shakesneider of the New York City Center Opera.

Jackson said that in his 12 years as director of the group, he has only had to ask one student to stop singing. The difficulty of the music and the long commute to Georgetown, he explained, weed out the less dedicated members. The chorale now meets once a week, on Tuesday nights from 4:30 to 7 p.m.

The group performed last week at a Black History Month celebration at the General Services Administration. The chorus sang a selection of music by black composers - only one aspect of the repertory.

"I don't want them (the members) to feel that because they are black, that is the only music that is worthwhile doing," said Jackson, emphasizing that the chorale performs everything from Bach and Mozart to Broadway tunes and folk songs of foreign countries.

Along with appearances at school board and other community events, and frequent performances at the Kennedy Center, the chorale has sung at special events across the country.

The group has just been invited to participate in "Fiesta '78," a choral program to be held next June in Mexico City. In order to go, said Jackson, about $500 per person will have to be raised.

The youth chorale receives about $63,000 a year from city school system funds, a sum that does not cover the shool-year activities and summer camp. The chorale and its parents' association raise additional funds through private contributions, grants, a benefit concert bake sales and car washes by the students. Fund-raising plans for this year's Mexico City trip have not yet been made.

The chorale has 50 regular members, and Jackson hopes last week's audition will swell the ranks. There are also an Elementary Chorale of 100 members and a Junior Chorale of 25 seventh and eighth grades that meet at LaSalle Elementary on Riggs Road and Madison Street NE.

Students who are interested in joining can makean appointment to audition by calling 282-0123.

At the close of last week's audition-rehearsal, Omego Ware beamed at his daughter Cookie, singing with the chorale for the first time. The group made a ragged, but resounding, attempt at "The Battle Hymn of the Republic."

"You hear that much noise," said Ware," and you know it must be a thrill to be part of it."