The station, at 89.1 on the FM dial and headquartered at Mercer County Community College with a 30-year history on the fringe of Philadelphia, is a bit of an outlier in radio formats, starting with its attitude toward punctuality.
"This hour of music doesn't quite start at 12 - and we don't care," said Hemmingsen as he prepared the first Curtis show early this month. "It might be a minute little more than an hour. Or less."
If there's glee in his voice - while a Curtis student ensemble launches into Jean Francaix's rarely heard Wind Quintet No. 1 - it's rebellion against his more mechanized first career: working with computer hardware and training at the Naval Air Warfare Center in Lakehurst, N.J.
Is WWFM the answer to everybody's prayers? That's not the point.
"The day I walk into a doctor's office and hear WWFM," says station manager Peter Fretwell, "is the day we've failed, unless the doctor happens to be a serious aficionado. Our goal is not to be played as background music. If it's art, it deserves full attention. Front and center."
He speaks with quiet confidence and quotes lesser-known Greek philosophers in his annual report to members, who now number a relatively modest 3,200 (compared with the 20,000-plus of Temple University's WRTI-FM), but they are loyal, and are often wealthy enough to offer substantial challenge grants, along the lines of $10,000.
The numbers don't need to be high to support this polar opposite of more typical classical-music success formulas - the ones that often strive for consistent mellifluousness, assuring that no wobbly-voiced sopranos or ultra-dissonant Stockhausen works assault listeners who stumble upon it.
Such consistency wouldn't come easily to a station that broadcasts concerts, both live and taped, from more than 30 music institutions, including the Princeton-based early music group the Dryden Ensemble, Piffaro (the Philadelphia Renaissance band), and the celebrated Bach at One concert series presented by Trinity Wall Street church in Manhattan.
Announcers do their own programming, often sifting through hours of tape from the likes of the Curtis Institute and deciding what makes good radio. "It's not as if we don't have any standards - like having to program one baroque piece every hour - but we interpret them differently" says Hemmingsen. Announcers are hired because they're experts, from Marjorie Herman on the Sounds Choral show to Ted Otten and Michael Kownacky for the Broadway-oriented Dress Circle.
Also, WWFM doesn't necessarily broadcast everything that's handed over from Curtis, the Manhattan School of Music, the Lenape Chamber Ensemble, and numerous others.
"Once we got a Manhattan School concert with a piece for snare drum that was 20 minutes long," said David Osenberg, who hosts the Cadenza show. "And I'm sure it was striking to see the exertion that went into it. But it wasn't radio material."
As on many classical stations, concert recordings by the New York Philharmonic and the San Francisco Symphony are in evidence. When the Metropolitan Opera broadcasts became too restrictive in station-identification matters, WWFM switched to La Scala in Milan.
One recent victory was securing broadcast rights to the Princeton Symphony Orchestra: It's the first unionized group the station has acquired firsthand, catching the institution during a period of artistic growth under Rossen Milanov, whose strong Philadelphia reputation (he was the Philadelphia Orchestra's associate conductor for more than a decade) reflects the station's new-found priorities.
Two leasing agreements, negotiated over several years, have broadened the station's spread: one with WKVP in Cherry Hill that started this summer, another with Columbia University's WKCR, which gave the station a New York City presence last year.
However advantageous its positioning in this rich Philadelphia-to-New York classical-music corridor, the catch is that both those stations are HD2. When high-definition digital radio arrived a few years ago, each signal came with four channels, only the first of which is needed by the consumer. The third and fourth channels are best saved for utilitarian purposes (sound quality isn't great) but the second channel is full of possibilities.
If only the listening public didn't need to invest in new hardware - an HD receiver that costs about $70 (usually with a CD player and an iPod dock). Such receivers are common in the United Kingdom, where the analog FM signal eventually will be shut off. No such deadlines have been set in the United States, so sales have been slower.
Also, WWFM's HD2 coverage of the Philadelphia market includes Center City but not outlying areas, such as Chestnut Hill, that have prime classical-music demographics. Without HD hardware, the FM signal from Princeton Junction can be heard in Center City, but not dependably.
But even with HD2 in a nascent state, Fretwell is confident of meeting the terms of the five-year agreements he struck at Columbia and in Cherry Hill. Roughly speaking, he needs a thousand new listener members both from Philadelphia and New York City - a more viable option than raising the $40 million to acquire a major FM signal.
Even if HD2 ends up fading in the quickly changing technological landscape, WWFM's contingency is Web radio. That's nothing new - nearly every radio station has had a Web presence for years - but with new vehicles increasingly being equipped with WiFi, Web radio now can be accessed without parking in front of one's home computer.
That option could also bring WWFM into competition with the heavily subsidized classical stations in England, France, and the Netherlands. But there's a reason why it already has scattered listeners as far away as Singapore: For all its lack of budget, the station is unlike any other.
"How many classical stations do you need if they're all doing the same thing?" asks Fretwell. "We're in a community college. We don't have deep pockets. Why joust with a guy who has deeper pockets? My only hope for surviving is to treat high art like high art and hope there are enough people who agree with that."
Contact music critic David Patrick Stearns at email@example.com.