"In between my last concert and my next one, I hate music," said Erich Kunzel, leaning back in a comfortable hotel chair, smiling and resplendent in a bright plaid jacket. Stuart hunting plaid, to be precise -- he is usually precise.

Then he pauses, a flicker of doubt on his face. Has he said something that America's hottest pops concert conductor should not say? He explains:

78That's what I told my dentist in Bangor this morning while he was doing my root canal. He asked me if I was going to hear the Bangor Symphony and I told him I had not heard the Bangor Symphony and would not until I conducted them.

78I don't go to hear even the great orchestras. I conduct them all."

Kunzel, 44, does conduct them all -- 100 concerts per year, including such prestigious orchestras as Boston, Cleveland, San Francisco and Chicago, as well as his own Cincinnati Pops Orchestra. But no more than 100, because "I keep it reined in," he says, pulling back hard on an imaginary bridle.

"One advantage of being a pops conductor is that most of the work is on weekends and there is only one rehearsal for each concert, so I can conduct in Washington tonight, do 'An Evening in Vienna' in Chicago Sunday night and still spend most of the week at home in Maine. Summer is the time when I go crazy. I often do five concerts a week, sometimes in three different cities."

With Arthur Fiedler's health failing, Kunzel is the heir apparent to the prestigious Boston Pops, where he has been a regular guest conductor for the last nine seasons. Reluctantly, he will admit that people from Boston have discussed his future, but he has made no decision.

One thing is sure -- he will not be conducting when he reaches Fiedler's age. "It is true that conducting seems to contribute to long-evity," he says, but "in 40 years I don't plan to be conducting anything. I plan to be sailing my boat in the Mediterranean."

Despite the Viennese-sounding name (actually German: 78There was an umlaut but my father dropped it"), Kunzel grew up in Greenwich, Conn., on Long Island Sound, and has been wild about water sports -- swimming, boating fishing -- all his life. He now lives on Swan Island off the coast of Maine, and he has arranged for nine work-free days next month so that he can bring his new power launch up from Cape Canaveral.

"We'll have to do a lot of our traveling in the open sea, weather permitting, to make it in that time,78 he says. "I'm bringing my caretaker along, in case I have to drop it off somewhere along the coast and fly away to do some conducting."

Kunzel decided to be a conductor "in my junior year at Dartmouth, when I got mad at my chemistry teacher and told him to go to hell. I had planned to be a chemist until I met this teacher.78 He had been playing the piano since he was 10 and had conducted a production of "Die Fledermaus" in the summer before his junior year. He began to study conducting with Pierre Monteux, became his assistant and still recalls him as "the greatest man I have ever met."

Kunzel is making his debut tonight with the National Symphony. His appearance here (and all over the map) is a part of a growing trend in American symphony orchestras -- a pop that amounts to an explosion.

New pops orchestras are being born.Washington's newest, the Beethoven Society Pops, gave its third concert last Sunday to a standing-room crowd of 1200 in the ballroom of the Capital Hilton. Tchaikovsky's "1812" Overture was featured, with cannon specially built for the occasion and balloons painted to look like cannon balls.

And old orchestras -- following the lead of the Boston Symphony, which began it pops series over 90 years ago -- are adding pops concerts to their schedule as fast as they can find specialists to conduct them.

Kunzel says of the trend: "Orchestras began adding pops concerts to extend their seasons -- they want 52-week seasons -- and they discovered two things. First, that a lot of people want this kind of music, and second, that there is money in it. These concerts are usually sold out.

"And the audiences get to hear and like the sound of a symphony orchestra -- some of them keep coming back to pops concerts and some become subscribers to the regular season."

It is hard to pin down what makes pops music "pop," other than its popularity. It is usually fairly brief, but so is most of the decidedly non-pop work of Anton Webern. It is almost invariably melodious, but so is "The Art of Fugue." It is usually fairly simple -- but that is a relative matter.

Bach's Little Fugue in G Minor has become pops music through the efforts of Arthur Fiedler, but it is more complex than most of Haydn's music. "Pictures at An Exhibition," the "1812" Overture and "Scheherazade" -- all standard pops fare -- have a complexity that would have baffled any orchestra in Beethoven's lifetime.

Two qualities are almost universal in the pops repertoire: a name more colorful than "Sonata in C Minor, Opus 30, No. 2"; and bright, lively orchestration.

That brightness makes National Symphony trumperter Adel Sanchez "ambivalent" about the music. Not only is the trumpet rampant in pops, but the trumpeter's stock in trade, the embouchure (as jazzmen call it, "the lip") is a delicate organism, hard to maintain in top condition.

"We are not playing any winter pops concerts next year," says Sanchez, "and I must say I'm glad. I prefer to play pops in summer. I rather enjoy it when I don't have to be keeping myself in very fine shape for serious music."

for a trumpeter, he adds, the pops repetoire is "demanding, physically taxing -- much more labor is involved than in serious music."

Not so for violinists: "Concertmaster Miran Kojian finds pops "something you play for the fun of it" but prefers music that is "more serious, more challenging."

Some of Kunzel's repertoire ("thousands of pieces") is ephemeral. Currently hot numbers are "A Fifth of Beethoven," "Saturday Night Fever," the music from "Star Wars" and "Rocky." He admits that he gets tired of it long before audiences or even orchestras do.

"It is also expensive," he complains. "To play this music with an orchestra, you have to get it orchestrated. And orchestration, with parts copied out, costs an average of about $1000 for a minute of music. Some of it doesn't last very long, either. A few years ago, everybody had to hear the music from 'Shaft' -- and then in a few months it was dead."

Despite the pops that put his annual income well into the six figures, Kunzel remains an avid devotee of classical music. He still recalls the day he studied the score of Debussy's "La Mer" note-for-note with Monteux, who had conducted the world premiere:

"Going over that score with Monteux, who had gone over it with Debussy when it was new: Those were the two most beautiful hours I can remember."