A staggering number of classical works have been written after, and about, the Sept. 11 attacks. There are string quartets, pieces written for local choruses, commissions from the New York Philharmonic, including on Sept. 30, the world premiere of “One Sweet Morning,” by John Corigliano.

Yes, there have also been pop songs, artworks, plays, novels and dance pieces about the event. But I don’t think any other field can show the density of commemorative works that the classical music world has produced.

As time passes and artists have opportunity to respond, new music starts to mingle with the familiar strains of the Mozart Requiems and Barber Adagios. Commemorative concerts represent a great opportunity for new work. Audiences that prefer traditional music over contemporary often let down their guard if the new work honors a tragedy.

Indeed, the association with a specific historic event has helped catapult some memorial works into the spotlight. In 1960, “Threnody to the Victims of Hiroshima” helped put the young Krzysztof Penderecki on the map. Benjamin Britten’s “War Requiem” premiered in 1962 for the rededication of bombed Coventry Cathedral, remains a go-to work of commemoration. And John Adams won the Pulitzer Prize in 2003 for “On the Transmigration of Souls,” though he said himself it wasn’t his best piece.

For memorial pieces aren’t always artistically the strongest; these days, especially, a certain political correctness has to be observed. Few memorial works today have the subversive punch of Shostakovich’s 13th Symphony, “Babi Yar” (1962), which commemorated a Nazi slaughter of Jews but was also a not-so-veiled critique of the Soviet regime. Today, commemorative pieces are too often of the ilk of the late Peter Lieberson’s “Remembering JFK (An American Elegy),” which the NSO gave its world premiere in January: attractive, tepid and showing very little of Lieberson’s real artistic personality.

And when Steve Reich chose to put an image of the burning towers on the cover of his upcoming CD, which includes his powerful commemorative piece “WTC 9/11,” there was such an outcry that he changed it.

Many commemorative pieces are born in part of a misinterpretation of the artist’s role. Art is often said to hold a mirror up to society; some draw from this the mistaken corollary that it is an artist’s responsibility to comment on memorial events.

Hence, I think, the increasingly documentary tone taken by many of these works, even those at the very highest level. Reich’s “WTC 9/11” is one of several 9/11 works that incorporate tapes from people who experienced the attacks. Reich uses 911 dispatchers, among others; Michael Gordon, in his 2006 “The Sad Park,” used preschoolers’ descriptions of what had happened. And hence the tacit public demand that such works represent the truth according to journalistic, rather than artistic, standards, as evidenced by Reich’s CD cover.

A result of such demands is that many commemorative pieces are the equivalent of incidental music, written for a purpose and retired after that purpose has passed. To make big statements, you need the artistic freedom to reveal even unpleasant truths, and no one wants to do that in a 9/11 work; the more accepted tone is one of elegiac prettiness.

It’s good news that so many big new works have been written for the upcoming anniversary: Corigliano’s “One Sweet Morning”; Christopher Theofanides’s opera “Heart of a Soldier” (to be premiered at the San Francisco Opera on Sept. 10); Robert Moran’s “Trinity Requiem” (commissioned by Trinity Church in New York, recorded by Innova Records); Stephen Paulus’s “Prayers and Remembrances” for a Sept. 11 premiere by the Tucson Chamber Artists; Richard Blackford’s “Not in Our Time,” which the Bournemouth Symphony will premiere in England on Sept. 11. They join an honorable catalogue of 9/11 works by Joan Tower, Anthony Davis and other notables; and, like them, some will endure and some will be forgotten.

The great thing is that they’re being written at all. Would that commissioners and audiences saw in new music a sign of celebration, as well as one of mourning.