When the pandemic forced the closure of arts venues everywhere, the Philadelphia Chamber Music Society (PCMS) reacted as some others did, continuing to perform and setting concerts aloft on the digital wind.

The move to online, though, brought something unexpected to PCMS, one of the nation’s busiest presenters of string quartets and piano recitalists: a new and viable business model.

It’s early days for online listenership and donations, but in the first few months of operations, PCMS’s digital enterprise has racked up some eye-popping numbers.

Viewership for the season’s first 13 events has averaged 3,200 per concert. For an in-the-flesh sell-out, about 350 listeners turn up to hear works of Schubert or Vivian Fung in the American Philosophical Society’s Benjamin Franklin Hall, just a few steps from Independence Hall.

PCMS’s online concerts have drawn a strong local following, with 63% of viewers from Pennsylvania and New Jersey. But about 20% of the audience has come from outside the United States, including Canada, Mexico, the U.K., Germany, India, Israel, and Japan.

Not everyone is tuning in from beginning to end. Average viewing time is just 18 minutes for the hour-plus concerts.

There’s one metric, however, that stands out as a marker of success. PCMS’s virtual concerts are technically free of charge, but the pay-as-you-wish donation model has drawn real money — an average of $7,500 in donations per concert.

This sum is at roughly equal to the paid ticket revenue PCMS typically collected pre-pandemic at APS for a concert by a popular artist.

“I guess I would say I am pleasantly surprised. We really had no idea how it would all pan out,” says Philip Maneval, PCMS’s executive director. “Our initial motivation was to try to put musicians back to work. They are struggling as never before. Many of them have been without almost any income since last March.”

So robust have donations been that “the concerts really are paying for themselves,” he says.

One viewer from California, new to PCMS, has sent in four gifts since online concerts began. They total $5,500.

This success, like any other since the pandemic’s arrival, must be considered a Pyrrhic victory. It was nearly a year ago that artists were suddenly idled and projects stopped cold. Survival of Philadelphia’s institutions is hardly certain. And when arts groups, including PCMS, return to full operations, no one should forget that some familiar faces in the audience will be missing.

Still, the pandemic has forced creativity and innovation. PCMS’s COVID-era concerts at APS have hosted, off and on, a small live audience — up to 25. This past Wednesday afternoon, Mozart rang in the hall. Clarinetist Anthony McGill, violist Milena Pajaro-van de Stadt, and pianist Gloria Chien could be heard rehearsing the Kegelstatt Trio for a performance with a socially distanced audience that night, and the hall, cleared of its normal crowd, revealed a much more live acoustic.

Is there a way to renovate the hall to make this beautiful sound permanent? Let’s hope so. More immediately, PCMS and APS are investing time and money in physical changes like more sophisticated cameras and lighting. The goal is a production approach and aesthetic true to PCMS fans, who want a generally no-frills presentation with the focus squarely on the music.

McGill appears in another, very different online approach, in a Chamber Music Society of Lincoln Center online show. Highly produced, edited, and art-directed, it is more music video than pure concert film.

PCMS’s online model might not apply to other arts groups. Each organization has its own set of fixed costs, union contracts, and logistical hurdles that must be weighed against factors like the existence (or not) of an endowment and the depth of a donor list.

Most arts troupes, though, are adapting to digital life.

Opera Philadelphia has so far sold digital passes and rentals to more than 1,500 households for its series of original-for-online operatic films. The Philadelphia Orchestra is selling between 1,400 and 1,500 tickets for its online concerts for $15 and $17 a pop — far cheaper than the ticket price for live concerts, which often hover near or above $100 each in Verizon Hall (with 2,500 seats).

“It’s orders of magnitude less than the revenue we derive from the live concert,” says orchestra president and CEO Matías Tarnopolsky. At the same time, “the expenses have not gone down commensurately.”

For all groups now, philanthropy is critical.

Hello from Brazil

PCMS has taken its share of hits during the pandemic. COVID-related travel hurdles have forced the cancellation of some of the group’s most individualistic artists, like pianist Imogen Cooper. But on the plus side, PCMS has folded tech into the “society” part of its name by hosting chats on YouTube where listeners weigh in during the concert.

“People pop in to say hello from Brazil, or other people ask serious questions about the repertoire, like someone who wants to know how Dvorak is perceived in the U.S. because they are in Eastern Europe,” says PCMS communications director Brian Potter. “Some people are expressing gratitude. It’s really across the board.”

Here, Google Translate is sometimes of limited help. “Until recently, he didn’t love the viola, and then he loved it !!!” wrote one listener, rather cryptically, in Russian, during Wednesday night’s YouTube chat as Brahms’ Viola Sonata in E Flat Major, Op. 120, No. 2 was being played.

Entertaining though the banter may be, PCMS says it’s important to reunite listeners with the in-person concert experience. Online, the sound of the piano during Wednesday evening’s concert was fine, but a shadow of what it had been earlier in the day at rehearsal heard live. The Hamburg Steinway, bought just before the pandemic by PCMS and its sister organization, the Marlboro Music Festival, might be the most lovely keyboard in the city at the moment. Listeners deserve to hear it in full.

And then there is the intangible thrill of music unmediated by an electronic scrim. ”The first time I went back after not hearing a live performance for a while, I had tears down my face,” says Maneval. “The experience of hearing it live again with people around me, it was such a beautiful thing.”

Although PCMS aims to continue online concerts in some capacity post-COVID-19, “we are doing all of this to supplement the core concept of chamber music, which is to experience our concerts in person,” says PCMS artistic director Miles Cohen.

Ideally, in the company of a few hundred others, though that could take a while.

In the meantime, “we have 25 very enthusiastic people,” says Maneval. “So they clap loudly.”

The schedule of upcoming PCMS concerts is available at pcmsconcerts.org.