IT REALLY WAS a sound idea. As a member of the staff of the National Symphony Orchestra, I wanted to expose my two sons to classical music at an early age. So my wife and I picked one of the orchestra's youth concerts, prepped the kids on what to expect and settled into our box seats overlooking the stage so they could have a bird's-eye view of the conductor and the musicians.

Shortly after the beginning of the first selection, our four-year-old covered his ears with his hands and critiqued quite audibly: "Too loud, daddy! Too loud!"

Meanwhile, my wife was slamming the famous, finger-digging parental powerlock on his seven-year-old brother, who just wanted to run between the seats.

And so we learned.

For those of us who enjoy classical music and assume that this passion has been passed on to our children (it's in the genes, right?), Washington is a town that seems to overflow with cultural opportunities to share with our kids.

Sometimes, however, when faced with the task of ordering tickets, trying to figure out what everyone in the family would enjoy and dealing with youthful attention spans, it seems all too easy to let the kids turn the MTV back on and to adjust your own headset, ease back in a friendly armchair and listen once again to that favorite piano sonata.

But even with our rocky start, my wife and I have found that the entire family can enjoy classical music outings, often with low cost and little hassle. With a bit of planning, even the youngest in your brood can come away humming some Haydn instead of "I'm a material girl."

Perhaps the most important tactic in planning a classical venture with the kids is to not try too hard to make it an "enriching experience." Emphasize the "fun" aspect of the concert instead of "Kid, you're finally gonna get cultured." That latter approach always makes my kids feel as though they're going to take a dose of medicine.

At the same time, some subtle maneuvers on your part can open your child to the concert experience. Some suggestions:

* Children like to visualize what they're hearing, and some concerts "see" better than most. Good examples are Haydn's "Toy Symphony" with its easily recognizable sounds; Beethoven's "Pastoral Symphony" with its images of tempest, peasant dance and rolling river; and the oft-played "Pictures at an Exhibition" by Moussorgsky.

I like to pick up a recording that includes selections from a concert that we're going to hear. You can overdo this, but it's exciting for children to realize that the piece being performed is the one they've heard on the stereo.

* Another fun activity before the concert is to have your kids incorporate music into their coloring and drawing. Why not gently inspire some of their drawing activity with music that they'll hear in concert? Kids' imaginations can do a lot with Rossini's "William Tell Overture" or Saint Saens' "Carnival of the Animals." "Peter and the Wolf," despite lots of repetition, still delights my two and they demand it over and over again.

* On the day of the concert, you have a choice in getting the kids ready. If your children enjoy the opportunity to dress up occasionally, it can be fun to make their concert- going a special event by wearing their best outfits and feeling very grown-up about it. Alternatively, depending on the setting for your musical experience, their favorite pair of "Osh-Kosh's" may be just the ticket.

* While it may be a good idea to briefly review concert etiquette (don't talk during the performance, stay in your seat, clap at the end of selections only), be realistic. Having sat through many a concert with an older, traditional audience, I think that we grownups have a lot to learn from the wonderful enthusiasm and awe felt by children during their early musical experiences. But take them to the bathroom before the concert starts.

* If the concert is symphonic, it may be fun for your kids to hear a little bit about the different sections of the orchestra and the instruments. There are some good recordings for children that highlight various sections and instruments; Benjamin Britten's "Young Persons Guide to the Orchestra" comes to mind. I also like to take my boys down to the edge of the stage at intermission or afterward so that they can see the instruments more closely.

What about the role of the conductor (if there is one) in all this? Studies suggest that 70 percent of audience eye contact is on the conductor, yet he (or she) is the only one not playing a note.

Fabio Mechetti, the National Symphony's new Exxon/Arts Endowment conductor, and frequent conductor of youth concerts, suggests that children often see the conductor as somewhat of a magician, creating all of this wonderful music with his magic wand. How many parents remember seeing Walt Disney's "Fantasia" and wishing that we, like Mickey Mouse, could have a turn on the podium?

* Above all, have fun yourself. Your own enjoyment and enthusiasm will be communicated to your children and make them want to come with you next time.

An excellent opportunity for the entire family to enjoy orchestral programming geared toward children and families is the Encore Concert Series, which will be presented December 14 by the National Symphony Orchestra in the Kennedy Center's Concert Hall. The series' two concerts, with a holiday theme, are just an hour long. Tickets are priced right for family budgets and the program is one that kids of all ages can enjoy.

The concerts will include performances by the Blue Sky Puppet Theater, which will join the orchestra to bring to life "The Snow Is Dancing" from the Children's Corner Suite by Debussy, and "The Musical Sleigh Ride" by Leopold Mozart. Additional selections to be performed include works by Rossini and Bartok. WHERE YOUTH IS SERVED

Here are some details on the NSO concerts as well as additional suggestions of musical offerings for your family.

FAIRFAX SYMPHONY ORCHESTRA -- Will present "Hansel and Gretel" on Saturday at 2 and 4 at Fairfax High School, 3500 Old Lee Highway, Fairfax. It will be performed performed jointly with The Opera Theater of the University of Maryland and Fairfax County Ballet. Tickets are $4. 821-8118.

PRINCE GEORGE'S CIVIC OPERA -- Will perform "Hansel and Gretel" Friday at 8, Saturday and Sunday at 3, Martin Luther King Auditorium, Bowie State College, Bowie. Adults $10; students $5; children 12 and under $3. 699-2459 or 338-4088.

OPERA THEATER OF NORTHERN VIRGINIA -- Will perform Gian Carlo Menotti's "A Bride From Pluto" Saturday at 7 p.m. at Thomas Jefferson Community Theater in Arlington. The theater says it's geared for children ages 8 to 14. Tickets are $6 for adults, $5 for kids. Call 243-5455 or 558-2165.

JEWISH COMMUNITY CENTER ORCHESTRA -- Will perform Benjamin Britten's "Young People's Guide to the Orchestra" and Rossini's "William Tell Overture" on Sunday at 1:30 and 3 at the Jewish Community Center, 6125 Montrose Rd., Rockville. It provides demonstrations of instruments; kids will also have the opportunity to conduct "Stars and Stripes Forever." Tickets are $2 for JCC members, $3 for non-members. 881-0100, ext. 700.

UNIVERSITY OF MARYLAND -- Both the Tawes Theater (454-6669) and the U of Maryland Chapel (454- 4183) will have seasonal, low-cost programs in the weeks ahead. Sunday and Tuesday at 8 p.m., choral music in the Chapel; and December 13, a Boy's Choir concert in Tawes Theater. Call for ticket information.

NATIONAL SYMPHONY ORCHESTRA -- "Holiday Happiness," Saturday, December 14, Kennedy Center Concert Hall, 11 and 1, with the Blue Sky Puppet Theater. Tickets: $5 & $3, call Instant Charge, 857-0900 or go to the Concert Hall Box Office for remaining tickets. Beginning at 10:15 a.m., free music in the Grand Foyer in front of the Concert Hall the day of performance. Similar family program on May 3, 1986.

KENNEDY CENTER -- As part of its Holiday Festival 1985, the center will feature on December 26 the New York Strings, some of America's outstanding young musicians ($7.50); December 28, the singing Christmas tree ($3.50); and December 29, the D.C. Youth Orchestra celebrating its 25th anniversary ($7.50 and up). All events are in the concert hall. Call 254-3600 for information on this and other programs.

SMITHSONIAN DISCOVERY THEATER -- Will present "Peter and the Wolf" by Prokofiev through January 4. Tickets are $3 for adults and $2.59 for those 12 and under. Call 357-1500.

NATIONAL THEATER -- "Saturday Morning at the National" with scheduled programs on Saturdays at 9:30 and 11 a.m. running from September through May, including puppet shows mimes, folk story telling, classical dance and chamber concerts. Free. 783-3372.