WE ARE TALKING POP now -- pop music. Pop with an edge, though. A heart. With whatever it is that know-nothing purists like me know is ticking inside a Rickie Lee Jones session or a Bruce Springsteen, Cindi Lauper or Ray Charles concert -- and know is missing from one by, say, Culture Club. Without knowing exactly why.

And please. All of you who do know exactly why, please stop here. Call me on the phone sometime and straighten me out, but right now just go away. I'm hoping to open a couple of doors here, not to shut any.

So I mentioned the first rule of the modern American music business already: Thou Shalt Not Make It. Well, the second rule -- the one most music makers in Washington live by -- is something maybe you've figured out by now. It goes:

Then Again, You Might.

And that brings us to singer-songwriters Jon Carroll and John Jennings, and to Metro -- the occasional Washington pop-funk- folk-whatever band that pianist Carroll and guitarist Jennings share with bass player J.T. Brown and drummer Robbie Magruder.

Metro plays about 90-percent originals -- what Carroll likes to call "future top-40." The band doesn't have many dates; in fact, none this month. Everybody is also doing other things.

But Metro is a vehicle. Something to take you in all kinds of interesting directions, whether you're a performer or just damn curious onlookers like you and me. And Metro, like many such vehicles, may wind up not going anywhere.

Then again, it might.

It has a somewhat better chance than most, for several reasons. Two are Brown and Magruder, each of whom will always make a decent living as the type of musician who hardly ever does anything fancy (and if he does, it's hard to tell, because he doesn't grimace and shuck around to make sure you know it's fancy). And as the type of musician who hardly ever does anything wrong. Both of them do this all the time, for money, whenever Metro isn't working.

Another reason is Jennings, who takes as many risks in songwriting and guitar-playing as he can and still come out with something that'll fool the guys in gutless radio. ("Yeah," he says. "What I look for in music is danger.") And who supports himself meanwhile -- and adequately -- doing radio jingles, both in his 16-track Alexandria basement and elsewhere around town.

Jennings is in the jingle trade partly because he can ape almost anything, of any style, that you've ever heard on six strings. He is still sane at 30, however, partly because of the stuff he plays that you haven't heard. This is the stuff he makes up.

And you haven't heard it probably because Jennings doesn't have a record contract, and because they don't let you introduce your band before a jingle. Last month, though, he finished a four-song demo, with the help of Carroll, Metro and Bias studios in Springfield.

"I'm sending out a letter with the demos that says, 'If you want to talk business, if you want to make money, I can figure out a way for you to do it,'it's very difficult for a record company to lose money on any band." Pause. "People spending $2 million, $3 million to record is criminal. It reinforces the myth that all people who are doing music are just pampered poofdas. A lot of people are working very hard just to get their point across. I can go into any studio in the world and record a really wonderful album for $20,000. And pay the musicians. I defy any record company to lose money on a $20,000 master."

Jennings' voice is soft, despite the words. "I don't think record companies are interested in making a little money," he says. "They're interested in Frankie Goes to Hollywood."

Probably Metro's best shot at record-world roulette, in any case, is the guy behind the piano. At 27, Jon Carroll is different from most struggling local artists who Just Might, partly because he Already Has. He was a songwriting half and singing fourth of the Starland Vocal Band ("Afternoon Delight," 1976, six weeks at No. 1, two million records sold). He wrote "Get Closer" inside the Beltway, and Linda Ronstadt liked it. And the people who make Close-Up toothpaste made a 30-second anthem out of it. (Which, strangely enough, helps Carroll and his wife Margot Kunkel -- another SVB alumnus, the others being Bill and Taffy Danoff -- pay more bills out there in their Falls Church home than either the Ronstadt record or "Afternoon Delight" royalties, Carroll says.)

Another clue to what makes Carroll different could be found in his response to the question: Can he, Jon Carroll of the original Starland Soft-Rock Pure-and-Simple Vocal Band, realistically see himself writing post-Twisted Sister, non-John Denver Era hits -- in a hit-music world that's increasingly fond of what Washington music writer and ex-performer Bill Holland characterized the other day as "rude, crude, sexually insinuative, infantile, sexist, dumb rock and roll."

"Oh sure," Carroll answers, quickly. "I already have. They're just not out yet. They're not hits yet." He thinks about this a second. "Not to sound overconfident or anything -- you know you can't count on anything in this business -- but audiences know. If you have a song that you play and people come up and request to hear it again, you know. But audiences have to hear it."

This is one good reason why Metro is around -- even though Carroll will tell you "there've been gigs where the piano tuner makes more money than I do." And it explains why Carroll is working on his own album project in New York. And with Margot and a longtime friend, Mike Cotter, on an original vocal trio. And with Keith Kilgoe and five others on an r&b recording project at Washington's Star Tech studios. And with singer- songwriter Chip Franklin on his self-produced album.

"And last night I got a call from a guy looking for somebody to sing 'God Bless America' before all the Bullets games," Carroll says. "The first thing I said was, 'How's the attendance?' " JON CARROLL AND METRO -- No dates in January, but Carroll performs January 19 with Billy Hancock at the Gentry, 406 Eighth Street SE. Jennings appears January 29-30 with Mary Chapin Carpenter at the Birchmere, 3901 Mount Vernon Avenue, Alexandria.