Rahav Segev for The New York Times

In an age when almost all concert tickets are bought online and come with a heavy surcharge, what can a lowly band do for its fans? Perhaps the only way left for an act to assert control is simply to walk up to a box office and hand over cash.

That seems an almost quaintly old-fashioned solution, but it was central to one band’s recent scheme to circumvent Ticketmaster’s surcharges.

As I wrote in Wednesday’s paper, String Cheese Incident, a jam band from Colorado with a long history of conflict with Ticketmaster, recently had some friends and fans buy $20,000 in tickets from the Greek Theater in Los Angeles and then resold them more cheaply through its own Web site.

Since the article ran, a number of readers have asked for more information about how ticketing works, and why the surcharges exist in the first place. It’s a complicated story, but one that any music fan should probably know about.

There are two basic reasons for the surcharges. One is convenience (yours). The other is profit (for several parties).

It can be easy to forget, but vendors like Ticketmaster save you time and effort. They act as intermediaries with theater box offices, selling tickets via a phone call or mouse click so you can avoid spending a rainy Saturday morning waiting in line at a theater 15 miles from home. That’s a service for your convenience, and you pay for it.

But why so much? For String Cheese Incident’s show at the Greek, the face value for two tickets is $99.90, but by the end of the order Ticketmaster charges $130.25 — a markup of 30 percent, typical for Ticketmaster as well as any number of other companies.

One of the semi-dirty secrets of the concert industry is that when it comes to ticket surcharges, Ticketmaster — by design — tends to suffer the most curses and shaken fists, but there are several other hands in the pot. Ticketmaster takes its cut for handling the order; so do credit card companies. But the theater hosting the event also gets a fee in exchange for giving Ticketmaster the right — usually exclusive — to sell its tickets. The promoter of the concert, which books the acts and takes the greatest financial risk, also takes a cut. Depending on the show, there may be other interested parties as well.

Performers, however, are generally excluded from these fees. That’s because they get most of the face value of the ticket — in this case the $99.90, before the 30 percent in charges are added on. Decades ago bands and promoters used to split this money more evenly, but as the economics of the industry have changed — largely through national consolidation and more competitive bidding — the balance has shifted to the benefit of the bands, with major acts routinely getting 90 percent, or even more.

Because of this, every other party involved in a show must find other ways to make money, and the easiest way to do that is through surcharges. That’s why Ticketmaster and many promoters oppose String Cheese Incident’s requests to sell up to 50 percent of their tickets themselves, without service fees. If they do, then a show’s promoter, theater and ticketer would lose half the income they would normally make on such sales. In the thin margins of concert promotion, that can mean the difference between profit and loss.

To get its tickets for the Greek, String Cheese Incident exploited a loophole in the system: many box offices waive or greatly reduce surcharges for walk-up sales. But in this case, even that loophole had a loophole. The Greek’s box office normally charges $3 per ticket on walk-ups. But Mike Luba, one of the managers of String Cheese Incident, said the band was able to get that fee waived for its shows. The Greek did not respond to requests for comment on Wednesday’s article.

As pointed out in the article, the tickets String Cheese Incident resells on its site are not totally without extra charges. Although there are no service fees, the band charges $12 shipping per order.