On the floor, John Hohl stands with his mustache draping his open mouth and his arms describing large circles, signaling a small horde of people standing on the risers: You haven't seen their like since your last office picnic -- young men with beards, old men with beards, gray heads, skin heads, men in slacks, men in jeans, men in sweaters, men in jackets. People, in short, with two things in common: their gender and their open mouths.

Out of those mouths pour, in four-part harmony, a little Barry Manilow, some 19th-century classics, a few spirituals, a little gospel music -- the kind of songs you'd hear at Disney World and, more to the point, the kind of songs you'd hear at a barbershop convention.

These are the Alexandria Harmonizers, champions of a six-state district for five of the last six years, competitors at the international convention of the 750-chapter Society for the Preservation and Encouragement of Barber Shop Quartet Singing in America (SPEBSQA), and one of eight chapters in the metropolitan area. "We are the best in the area," says Terry Jordan, baritone with a beard, "but some people don't like this level of competition -- rehearsals every Tuesday and some Thursdays and Saturdays."

Some people, though, thrive on it. "It keeps me sane -- you can quote that," says Mike Everett, who sings bass with the chorus and with one of the most active of its seven quartets, the Friendship Fire Company.

"Barbershopping has a leveling effect: It brings people together," he says. "I travel a lot, and in every big city I can pick up the phone, call the local barbershop group and tell them where I am. And that night some strange guys will pick me up, take me to dinner and bring me to their rehearsal."

Rehearsals are a weekly affair for all the chapters in the area, where directors teach and polish the repertoire for monthly or bimonthly performances in old-people's homes, Lions Club meetings, parks and other community centers. But membership in a quartet can triple the rehearsal time and double the performances -- many of which are out of town.

"My kids call me Uncle Daddy," jokes Scott Werner, the Harmonizers' former director and member of a quartet that took third place in the last international competition. "We decided to limit our out-of-town engagements to twice a month," he says evenly. "It can lead to marital problems."

Most groups -- indeed, most barbershoppers -- are not quite as caught up in this "commanding affliction," as old- timer Joe Craig calls it. The singers tend to be men who heard about barbershoppers through friends, co-workers, school music directors or -- like Craig -- in barbershops, and come along to a chapter meeting just for fun.

Some, like the Rev. Joe Witmer, a priest with a bit of an Irish brogue, do it "for escape -- I don't have to keep up the role here." But many in this highly mobile area find it a way to quickly find companionship. "Barbershop is a ten- letter word meaning friendship," says Everett.

Isn't this just a way for men to get away from their wives? "It isn't that much of an escape," Craig says. "We have a ladies' auxiliary that comes and supports us," he explains, and women have their own barbershop group to join, if they care to -- the Sweet Adelines.

"What brings us together is our love of singing barbershop," says Witmer, a statement that shouldn't be stretched to mean that these men necessarily know much about singing or that they are good singers. Being able to read music is not a prerequisite; anywhere between 50 and 90 percent of most chapter members can't.

"Soloists have a hard time adjusting to us," says Jordan. "We can't stand the vibrato." A member of the Sweet Adelines confirms this perception: "Most of us don't have really great voices singing by ourselves -- it's too painful to listen to," she says. "But when you put them all together, it sounds wonderful."

What they're putting together in this 19th-century, original American art form is, in essence, a four-part chord. Tenor, baritone and bass singers, by listening carefully to the lead, maintain that chord wherever feasible throughout a song.

If it's done right -- and if all the singers use the same pronunciation (so "where" comes out "ware" and not "whir") -- the lowest three voices generate the tenor in what they call an "overtone," a moment barbershoppers feel is "truly inspiring."

To get to this point, the groups put newcomers through a training program. Alexandria's is a bit more elaborate than most: "We take them (guests) into a back room for privacy, to determine their voice range," explains Jordan, "and then put them in that section" -- tenor, lead, baritone or base.

There, the newcomer is told to lean on the others to learn his part -- something all chapters advise. In addition, the Alexandria group provides a practice tape that gives both the singer's part and the whole song with his part left out.

Whenever the auditioning singer is ready, he can make up an impromptu quartet, take it to the back room again and sing before the Harmonizers' director. "We don't let the crows in," says Jordan -- a policy that distinguishes the Harmonizers from a few other groups in the area who are more interested in fun than competition.

Once you're a member, Jordan cautions, you still have to prove yourself before you can join the chorus in singing for outsiders -- and that requires memorizing part of the repertoire. Singing for the contests calls for even further polishing. That kind of discipline, Jordan says, traditionally puts his group at the head of their district and last spring gave them a sixth place in the week-long, international competition in Seattle.

There, in banana-yellow tuxedos, the Harmonizers lifted ther mustaches and their mouths to sing, "with three million voices singing together, what a happy sound." If the smiles on their young/old faces mean anything, it must be true.

The following barbershop groups in the area say they welcome "anyone who likes to sing." BARBERSHOPPING FOR MEN . . . D.C. SINGING CAPITAL CHORUS -- 460-5996. 55 members, three quartets. Annual dues: $50. Emphasizes quartets rather than chorus. Simple audition; singer needs to have a sense of pitch and be able to memorize music. MARYLAND KNIGHTS OF HARMONY -- Bowie. 577-3679. 62 members, three quartets. Annual dues: $50. "Looking for anybody, as long as he's a man." Meet Tuesdays at 3901 Woodhaven Lane. HOMETOWNE, U.S.A. -- Montgomery County. 649-6050. 88 members, four quartets. Annual dues: $48.06. Meet Tuesdays at Walter Reed Annex, Forest Glen. Annual show on October 29 at Einstein High. "Even if they're tone deaf, we won't throw them out." MARYLANDAIRES -- Prince George's County. 721-9684 37 members, two quartets. Annual dues: $40. VIRGINIA ALEXANDRIA HARMONIZERS -- 529-6120. 170 members, seven quartets. Annual dues: $44.75. Meet Tuesdays at Chinquapin Recreation Center. District champions; highly competitive. ARLINGTONES -- 549-3869. 72 members, five quartets. Annual dues: $45. Meet Tuesdays at Gunston Center. "Not strictly oriented toward competition." Pride themselves on their annual show -- "We're a bunch of hams." BULL RUN TROUBADOURS -- Manassas. 594-2310. 28 members, no registered quartets. Annual dues: $52. Presently looking for a director. FAIRFAX JUBIL-AIRES -- 960-8803. 111 members, five quartets. Annual dues: $44.75 plus one-time $7.50 membership fee. Audition for voice placement. "If the man can't carry a tune, he can still join, but he can't participate in contests." Rehearse weekly at the North Campus of George Mason University. . . . AND FOR WOMEN MARYLAND MARYLAND SOUNS -- Prince George's County. 474-1750. 30 members. Annual dues: $100. "We're the warmest, friendliest group," they say. Actively looking for a director. METROLARKS -- Rockville. 977-5413. 68 members, two quartets. Annual dues says. "But when : $90. Meet Tuesdays at Montgomery College. "Quite competitive," they say. VIRGINIA ALEXANDRIA SWEET ADELINES -- 780-1926. 30 members, two quartets. Meet Wednesdays at Lee Center. Annual dues: $60. On September 16, they'll celebrate their 30th anniversary at the Lee Center; the public is invited. COUNTRY CHIMES -- 369-2143. 20 members. Dues: $6 per month. Meet Thursdays at the Nokesville Church of the Brethren, Nokesville (near Manassas). POTOMAC HARMONY -- 841-0405. 70 members, three quartets. Annual dues: $75; partially funded by Arlington County. Combination of Fairfax and Arlington groups. Meet Wednesdays at Gunston Arts Center in Arlington. A "very competitive chorus." VIENNA FALLS -- 960-1267. 85 members, three quartets. Dues: $120. Meet Tuesdays at Vienna Elementary School. Regional champions; going for international competition in 1984. Annual show December 3.