Charles Miller knows music, but it’s mostly in the classical vein. He’s been called one of D.C.’s most brilliant organists and his office at National City Christian Church is well stocked, as one might imagine, with CDs, hymnals, file cabinets full of scores and scholarly books on music. It’s easy to throw him, though, when it comes to pop.

When asked if the title of his new organ recital series, “Magical, Mystical, Musical Machine,” which resumes today at 12:15 p.m., is a play on words of the similarly monikered Beatles album (“Magical Mystery Tour”), Miller says the thought never occurred to him.

“No, actually,” he says. “It’s just something I created myself. What I wanted to do was get something with some sort of title that was going to grab people … something other than the National City Christian Church organ series, which is as boring as Wonder Bread. And it’s worked.”

The series had existed for about 25 years at the large D.C. church, an architectural wonder that anchors Thomas Circle, but was struggling. Thursday was its normal day and it featured a wide array of performers on various instruments, not just organ. Miller and others at the church retooled it after a hiatus. “Machine” debuted in September on Fridays and was an instant hit.

Miller says attendance has tripled. And all the recitals, which are free, are performed on the church’s mammoth 7000-pipe Moller organ, the third largest organ in Washington (only organs at National Cathedral and National Shrine of the Immaculate Conception have more ranks, though National City’s is the only D.C. organ with five manuals, or keyboards, a distinction Miller says is necessary to play the church’s gallery organ in the back).

That makes it distinctive enough that organists from around the country are itching to play it. Miller says he gets unsolicited requests weekly from players willing to donate their recital time to the church. Miller has taken many of them up on the offer. Several are scheduled for “Machine” recitals, which run every Friday through May.

Stephen Harouff, a Peabody graduate who lives in Baltimore and plays at Faith Presbyterian Church there, plays at National City on Feb. 19. This will be his second recital there.

“It’s interesting,” he says of the National City organ. “It’s not often that you can go and sit at an instrument and have everything you need for any style of organ music … it’s pretty stellar.”

Miller kicks off the series return with today’s recital. He plans a toccata by J.S. Bach, a trumpet tune by David N. Johnson, an adaptation of on operatic intermezzo by Pietro Mascagni and a movement of an organ symphony by Louis Vierne.

And though Miller didn’t plan it, all the players booked for the series in February are gay (openly gay David Christopher of Wilmington, Del., plays Feb. 12. The month ends with another recital by Miller on Feb. 26). Miller guesses about 75 percent of U.S. organists are gay men.

Miller says why that’s the case is “the million dollar question.”

“I don’t know if it’s because as young musicians the pipe organ is such an odd, well, odd is kind of a weird word, but people don’t readily seek out to play the pipe organ. You’re more likely to say, ‘I’m gonna play the trumpet, or the flute, or the piano.’ So I can see in many instances if you’re a young child struggling with your sexual identity, you’re kind of off the beaten path anyway, you feel unique or isolated or weird. I guess maybe that could be it, but it’s very difficult to know and it’s a phenomenon unique to the U.S. It would be a great sociological study.”