Being back in town and back at work is no reason to sing the blues--unless you can get some some other folks to sing along so everybody has a good time. There are dozens of singing clubs and choral societies in the city and suburbs where all are invited to lift every voice and sing everything from barbershop harmony to Bach. It's fun and a far better way to meet people than singles bars. If your tastes are more dramatic, there are little and not-so-little theaters with open auditions. And there are sports and outdoors clubs, dance and arts groups, bands and symphonies, fun bunches--we name it, and you can join. Read on.

It's not official yet, but many local choral conductors are saying that Washington is the choral capital of the country and "maybe the world," adds University of Maryland Chorus director Paul Traver. As evidence, they offer quantity -- more than two dozen medium to large choral groups in the metropolitan area -- and quality, with groups sought after by the likes of Leonard Bernstein and the National Symphony.

Some imaginative reasons are given for this phenomenon: THEORY I -- "This country is turning out music majors like Detroit turns out cars," says Barry Hemphill, the Arlington Metropolitan Chorus' energetic leader, "only there are no jobs for music majors. So they give up and become civil servants, but come here wanting to sing." THEORY II -- "This is a highly intelligent town," says Robert Webb of the Springfield Community Chorale, "and the smart kids in school tend to be in the band or the chorale. When they come to Washington, they miss whatever it was they got in the chorale in school, so they join up here." THEORY III -- "It's better than hitting the singles bars," says Phyllis Hubble of the Alexandria Community Singers. "About a third of our members are single -- it's a great social thing." THEORY IV -- "It's primal scream therapy," says Steve Nixon of the Laurel Oratorio Society. Says another choral member: "It's very satisfying to work as hard as you do on these works and have them turn out as well as they do. There aren't too many jobs like that in this town."

The "hard work" description certainly seems accurate. All of the 25-plus local choral groups rehearse weekly, and many pile on extra rehearsals as concert dates draw near. For those who make it through the rigorous auditions of the top groups, concerts practically become a way of life -- a way that swallows annual leave, evenings and weekends.

The groups also swallow extra cash. Including dues, music and costumes, many singers end up paying more than $50 each year to indulge in their vocal avocation. "And that doesn't count the cans of pecans their families buy for our fund-raisers," says Kate Baschuk of the Fairfax Choral Society.

But for anyone wanting to learn more about the fine art of choral singing, this is the time of year when many groups are looking for members, and the opportunities seem unbounded in this town. There are small groups such as the New Century Singers (they do American composers) and Musikanten (they specialize in Renaissance music); large groups such as the Washington Cathedral Choral Society ("We're a big group doing big works in a big place") and the Reston Chorale (100 singers doing classical works -- including newly commissioned pieces).

There are specialty groups such as the Bach Consort (as in J.S. Bach) and Kwanzaa, a group dedicated to black composers, and semi-professional groups such as the Choral Arts Society and the Oratorio Society -- groups that demand the highest-quality, best-trained voices to sing at the Kennedy Center and with the National Symphony.

Quality and training vary widely from group to group, but anyone with a choir or choral-group background is bound to find a niche in this town. "You're in no position to judge your own voice qality," advises Hemphill, who adds that, if you're new in town and sang recently with a choral group, you should "come to me first!"

Most directors advise potential members to shop around, sit in on a few rehearsals and a few concerts, and see which groups suit them best. Then call up the conductor and make an appointment for auditions, checking to see if you should bring a prepared piece.

"If you don't make it, try to find out why," says Hemphill. "You may have a wonderful voice, but it just isn't the range or type I need. Or sometimes it's something like sight reading, which you can bone up on for the next audition."

Church choirs are the places to go if you have little or no training, say the directors (many of whom lead such choirs on the weekends), and suburban groups tend to be good for those with training but less time to put into their singing. Skipping rehearsals is a deed punishable by wrath in most groups, so the directors advise new members not to join unless they're committed. This is especially true in the smaller groups, where the loss of even one voice in a section is quite noticeable.

In the following list of groups, I've tried to indicate the difficulty of the auditions, the time and financial commitment required and the type of music sung. Missing from this list are the dozens of madrigal groups, school and children's choruses and chorales-for-hire that populate this town. Even so, there are plenty left to pick from: COME, SING A SONG D.C. BACH CONSORT -- 527-7070.

This group concentrates on the works of J.S. Bach. Auditions for 40 singers are held in August and all members re-audition annually. The emphasis is on timbre, intonation, sight reading and range. Rehearsals are on Sundays in Arlington for the seven-concert series (plus extras). Director J. Riley Lewis is a former Washington Cathedral choir boy who took his doctorate at Juilliard and works as associate conductor at the Choral Arts Society and the Cathedral Chorale. CHORAL ARTS SOCIETY -- 244-3669.

This group concentrates on classical choral music. The 180 singers re-audition each year in a session that includes vocal testing and sight reading; considered one of the more demanding groups, its members sing in the Kennedy Center and this year have made 15 formal appearances. Director Norman Scribner founded the society in 1965 and also works as assistant organist at the Washington Cathedral. He has taught at American and George Washington universities, and has been chorus master for the Washington Opera. No dues, but members must buy their own music and costume. Weekly rehearsals plus extras before concerts; some matinee performances. GAY MEN'S CHORUS OF WASHINGTON, D.C. -- 726-0729.

This chorus performs a wide variety of music -- renaissance to American folk. Auditions on September 14, 15 and 18 will test for voice placement and sight reading, labeled "moderately difficult." The two-year-old group, which has 85 singers, rehearses Sundays at the First Congregational Church for three yearly performances. You don't have to be gay, "but you have to sing under the banner of the Gay Men's Chorus." NEW CENTURY SINGERS -- 396-5879.

They sing music by American composers, usually 20th-century. Auditions are held any Tuesday for a place among the 20 singers; they're looking for voice quality and placement rather than training. The eight-year-old group charges $15 per year for dues, and members must supply their own costume. They rehearse Tuesdays in Christ Methodist Church for their dozen yearly concerts. Director Robert Johnson trained by directing church choirs for 20 years. ORATORIO SOCIETY OF WASHINGTON -- 762-5669.

This 20-year-old group specializes in oratorio, a form of religious opera. Auditions for its 130 members are among the toughest in the area and include general musicality, sight reading, singing in groups and solo work. The society rehearses Mondays in Bethesda for its nine to 12 yearly concerts, most done in conjunction with the National Symphony. Director Bob Shafer studied in France and is considered one of the most competent musical directors in town. Dues: $35. PAUL HILL CHORALE -- 365-2770.

This group's broad repertory includes Gilbert and Sullivan, 16th- century madrigals and Cole Porter, but it tends to do more popular works than the other major groups. Auditions for the 150 members, held in May and June, are considered difficult. Auditioning singers must read a familiar piece, sight read an unfamiliar piece and be judged on voice quality and range. The group was founded in 1967 by Paul Hill, who has done graduate work in conducting at the University of Southern Califordinia. The group performed at the formal opening of the Kennedy Center. Eighteen singers from the group are paid and most of the chorale members have some professional training. Soloists are often picked from the chorale. This is a big time commitment. THOMAS CIRCLE SINGERS -- 387-0083.

This group performs predominantly classical works, madrigals and chamber pieces. Auditions for 30 members, to be held September 13 and 14, will check for voice quality and sight reading. Dues are $30 per year, which includes music and costumes. The group rehearses Tuesdays at Luther Place Memorial Church on Thomas Circle for the four yearly concerts. Director Stephen Greene started the group in 1976 after graduating from Westminster Choir College. WASHINGTON CATHEDRAL CHORAL SOCIETY -- 966-3423.

Founded 41 years ago by Paul Callaway (who also started the Washington Opera), the group has 250 singers who do "big works in a big building," most of it classical, sacred music. Auditions, which will be on September 12, 19 and 26, are considered tough and include vocalizing and sight reading. Bring a list of places where you have sung in the past. Rehearsals are on Mondays, plus two dress rehearsals before each concert; members are expected to practice between rehearsals. Dues are $30 per year and include the use of music and choir robes. WASHINGTON MALE CHORALE -- 581-7987.

These singers perform "any classical music suited for the male voice." Many members are graduates of Woodson Senior High Male Chorus. To audition, you should bring something to sing: the group is interested more in voice quality than in sight reading for its 24 members. There's no fee to join, no dues, and music is furnished free; members wear tuxedos to concerts. Rehearsals are Saturdays at All Souls Church, 16th and Harvard streets NW. WASHINGTON SAENGERBUND INC. -- 585-7383.

The oldest singing group in the area, it says -- it sang at Lincoln's funeral -- performs strictly German music, usually folk music. Rehearsals are held Fridays at the Concord Club for their five to six yearly performances. Director Michael John also heads the music department at the German School in Potomac, but the group's 90 singers don't all speak German. MARYLAND BELTSVILLE CHORALE -- 431-2476.

Classical works, renaissance to contemporary, are this group's focus. Auditions this September and in January for 20 members involve singing a familiar piece and checking for tone quality, range, color and sight reading. Rehearsals are on Sundays at Beltsville Presbyterian Church for three yearly concerts. The group also sponsors choral workshops and brings in coaches on such topics as Gregorian chant and opera. It is looking for a director. Dues are $15 per year, and members must buy own music and costume. BOWIE-CROFTON CHORAL SOCIETY -- 262-5911.

This group does classical performances plus one pops concert each year. Auditions for the 80 members are held anytime and look for top and bottom of voice range, ear training and a little sight reading ("It's important, but we'll let them in if the concentrates on classical music. There are no real auditions for its 30 members, but singers must be able to read music. Rehearsals on Mondays at Duval High School. Director Edmond Lewis has a master's in music from North Texas State and is doing doctoral work in musical arts and composition. KWANZAA CHORAL ENSEMBLEE-- 350-4459.

The ensemble concentrates on black music -- classical, soul, jazz, spiritual, folk -- but welcomes all races. A spokesman says auditions are "very easy" for its 20 members: voice placement is checked but there's no sight reading. The group rehearses Monday nights in the Seat Pleasant area and gives concerts twice per month. It's free to join and the group is partially supported by the Maryland National Park and Planning Commission. Members are expected to help with fund-raising. LAUREL ORATORIO SOCIETY -- 725-8404.

This 70-member group performs "serious classical music." Informal auditions check for voice placement. The 14-year-old group rehearses Mondays at Laurel Senior High for four yearly concerts. Director Marc Tardue studied conducting at Peabody Institute and is currently conducting the Icelandic Opera Company. Dues are $15 per semester; members furnish music and costume. MASTERWORKS CHORUS -- 468-4172.

It sings classical works and holds auditions through September 11 (call Fred Felmet at 589-5692) for 100 members. The chorus is looking for people who can "read music well." Rehearsals at Richard Montgomery High School are every Wednesday for three major concerts per year. MUSIKANTEN -- 530-8548.

This group concentrates on Renaissance music. Summer auditions for the 16 members included range, breath control, flexibility and sight reading. Rehearsals are every Wednesday, with extra rehearsals before their 30 to 40 performances. Director Kerry Krebill also leads the Alexandria Choral Society (see below). There are no dues, and costumes and music are provided. ROCKVILLE COMMUNITY CHORUS -- 424-8000, Ext.357.

The group sings a mixture of classical and pops. Auditions for the 50 members are by special arrangement and involve scales, singing a prepared song and some sight reading. Director Tom Allen recently completed his master's in choral conducting at Catholic University. Dues are $12 annually, including music. PRINCE GEORGE'S CHORAL SOCIETY -- 559-2005.

This year is the 21st anniversary of the 70-member group which sings classical and pops. Auditions involve voice placement only, no sight reading. Rehearsals are on Mondays at Seabrook Elementary School for one large concert and several small ones annually. The group includes some high-school students. Director Ron Freeman is a singer who also teaches voice and piano. UNIVERSITY OF MARYLAND CHORUS -- 454-4183.

The chorus sings 90 percent classical, with an occasional special program. Tough auditions for 240 members (students and community) will be held September 9, 10 and 11 to check for voice range, sight reading and memory. Rehearsals are on Tuesdays for seven yearly concerts. Director Paul Traver, who has a doctorate from Stanford in choral conducting, founded the chorus 16 years ago and also directs the Wolf Trap Chamber Singers and St. Mark's choir in Adelphi. Dues are $15; members furnish music and costume. VIRGINIA ALEXANDRIA CHORAL SOCIETY -- 998-9125.

The group does baroque to contemporary classics. Auditions for 45 members check for vocal range, sight reading and memory. There are Tuesday rehearsals as well as extras before concerts, and members are expected to practice at home. Director Kerry Krebill has a master's in choral conducting from Cath participants must bring a prepared popular song and go through scales and voice exercises. Some people in the group don't read music. Reheaarsals are on Tuesdays for two major concerts and many small ones annually. Dues are $7.50 per season, plus music and costume. ARLINGTON METROPOLITAN CHORUS -- 558-2161.

This chorus performs mainly classical works. Auditions for 80 members test for quality control, scales and sight reading. "Out of the last hundred I've heard, I may have taken ten," says director Barry Hemphill, who trained athe the Manhattan School of Music and sings with the Army Chorus. Weekly rehearsals are held at Gunston Arts Center in Arlington for four concerts each year. Dues are $45 annually, including music. FAIRFAX CHORAL SOCIETY -- 620-2558.

It gives classical performances, plus one pops concert annually, and does traditional Christmas carols in December. Auditions, which will be on September 10 and 11, are considered "moderately tough -- not as tough as the D.C. groups," a member says. The 85 members must do some sight reading. Weekly rehearsals prepare for four annual concerts. Dues are $30, plus music. MOUNT VERNON SINGERS -- 780-1377.

This nine-year-old group does a mixture of classical and pops. Auditions, to be held September 9 and 10 for 25 members, include voice placement; no extensive sight reading. Dues are $35 annually, plus music and costumes. Three major performances per year. NORTHERN VIRGINIA SYMPHONIC CHORUS -- George Mason University. 425-3900 or 323-2000.

The group does classical works, including community sing-alongs. Auditions for the 80 members (students ands community members) are "fairly simple." They look for vocal range, pitch and sight reading ("No one makes it through all the sight readings," the director says). There are no dues; the university supplies music and costume. RESTON CHORALE -- 437-9614.

This 16-year-old group does classical works plus pops and Gilbert and Sullivan. Auditions for the 100 members, held last week this year, are "simple -- no sight reading." There are weekly rehearsals for four annual free concerts.Annual dues are $30, plus music and costume. SPRINGFIELD COMMUNITY CHORALE -- 250-7096.

This group does major choral works plus some pops and is designed for "fun and fellowship." Auditions for the 60 members include some sight reading. Rehearsals are on Mondays for the three major concerts plus less formal appearances given each year. Dues are $5 annually plus music and costumes. Director Robert Webb took his master's at Catholic University in music and is now working on his doctorate in conducting and playing trumpet with the Navy Band. OTHER VOICES

Here's a pastiche of other area singing groups specifically looking for new members this fall: AD HOC SINGERS -- Chamber chorus seeks members. Rehearsals every Monday at 7:45 at Reformation Lutheran Church, 222 East Capitol Street. 543-4793. CHILDREN'S CHORAL SOCIETY -- Seeks boys and girls, 10-14, to tour nationally and to England in '84. Perform sacred, classical, folk and pop. Tryouts September 13 at 7:30 at Chevy Chase Presbyterian Church, 1 Chevy Chase Circle. 301/681-8540. D.C. YOUTH CHORALE -- Auditions scheduled for first two weeks in October; senior division, grades nine to 12, with opera workshop at Ellington School, 35th and R streets NW.; elementary/junior division, grades three to eight, at LaSalle Elementary School, Riggs Road andMadison Street NE. 282-0096 or 282-0123. FAIRLINGTON SINGERS -- Informal group open to men and women. 637-6238. JEWISH COMMUNITY CENTER -- Of Northern VIrginia seeks members for adul Vinson Hall. 6251 Old Dominion Drive, McLean. 938-3001 or 532-3016. OPERA THEATER -- Seeks mezzo-sopranos, baritones and basses. For audition call 434-9082. POLYHYMNIA -- A mixed nine-voice chamber vocal ensemble seeks a tenor. Must be a good sight-reader. Call Jim Klumpner, 377-3308 (days) or 483-9106 (evenings). SHIR CHADASH CHORALE -- Performs Jewish secular and sacred music. For audition call 424-7677 or 632-3665. SOUTHERN MARYLAND CHORAL SOCIETY -- Auditions on September 10 by appointment at Bethany Christian Church, 71d athe28 Allentown Road, Camp Springs. 868-0527. VICTORIAN LYRIC OPERA COMPANY -- Needs members for light and comic opera who are over 16. 460-8622. WASHINGTON CONCERT SINGERS -- Singers needed for Verdi Requiem to be televised from Kennedy Center. 552-3944.