I've always wanted to have a garden party and hide a flutist behind a tree so music floated out like the pipes of Pan.

I have a friend who yearns to be serenaded by a brace of tuba players, all blatting in unison just for him.

He can rent that blatting tuba. Or hire a group playing Renaissance instruments to gambol across the lawn or have a Mexiican fiesta where the guests stuff themselves on tacos while a guitarist plays malaguena, or buy beer and bratwurst and invite the whole neighborhood in for a polka party.

If I were my friend I would hesitate to hire a tuba player until it was winter and we could all sit around indoors where the neighbors couldn't hear, but the other serenades are soft enough for a summer night.

They are not, however, as cheap as asking you nephew to play his trumpet, so perhaps a musical garden party should be shared with other hosts and hostesses.

Following are some of the sounds available. Give as much notice as possible. Even though a last minute call may find someone free, chances of finding the musicican of your dreams are better if you plan ahead.

DAVID R. ARNOLD, 573-0055, plays the guitar, $65 for three hours. "I do pop music like 'Feelings' and some bossa novas and Spanish music. I stay away from 19th-century classical guitar and baroque." Arnold plays Monday nights, 9 p.m. to midnight, at the Afterwords Cafe Kramerbooks, 1517 Connecticut Ave. NW.

RENE BERBLINGER, 331-1331, also is a guitarist, playing classical and contemporary, but "soft music," he says, "I also do serenades. I did one recently for a guy who was giving his girl a picnic on the Capitol Mall." He works alone or with a flutist. For Berblinger only, it is $50 to $60 fot the first hour, $30 for the next and $20 for the third - usually $100 an evening. Add a flutist and it's about $150 an evening. Berblinger plays at La Brochette, 1825 M St. NW, between noon and 2 p.m. on Tuesdays and Thursdays.

MERV CONN, 593-5711, used to provide music for the Washington Senators games. Now to hear him play his accordion or cordovox costs $60 an hour with a four-hour minimum on weekends and a three-hour minimum during the week. He plays a wide variety of music, including polkas.

DAVID PERRY, 387-2826, will play Renaissance music on the lute or guitar while strolling through your party singing Renaissance songs. He also can provide a Renaissance consort of lute, recorders, and viola da gamba playing Renaissance dance music. In addition, "We're in touch with people who play everything from traditional music of the British Isles to bluegrass to jazz and cabaret songs." Everything, in fact, but popular music. Minimum rate is $150. The more musicians, the more money. You can hear David Perry play at The David Perry Guitar and Lute Shop, 1604 20th St. NW.

SHOW BIZ PRODUCTIONS, 723-4215, in addition to handling a variety of other musicians, acan provide an accordionist for your polka party. $125 for three hours. CAPTION: Picture, no caption