In the arts realm, access is a dry word for what has emerged as the most urgent concept of our time. Classical music has often sat off to one side waiting for listeners to come to it, but it is now confronting the barriers that stand in the way.

This fall's list of concerts reads like an essay in access. For some, the barrier is financial, which makes free concerts like Opera Philadelphia's annual broadcast on Independence Mall Sept. 29 more crucial than ever. The opera itself, last season's We Shall Not Be Moved, uses the 1985 bombing of the MOVE compound in West Philadelphia as a jumping off point to look at the here and now.

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And speaking of opera, access can be about feeling like the traditions and structures of the genre as so well-established that you have to be an expert to participate. The O18 festival removes walls real and imagined around the art form once again, particularly with an immersive experience at the Barnes, Glass Handel, that mixes opera, art, fashion, film, dance, and live painting. (What, no celebrity chef cameo appearances?)

The barrier to classical can be stylistic, and a good many works this fall make the case that we've spent too much time focused on the rise and swoon of compositional schools and too little time thinking about the value of wide appeal. The Philadelphia Orchestra reconsiders traditionalists with two works: the Barber Piano Concerto and Menotti's Amahl and the Night Visitors.

Image matters, too. Black Violin, the classical-based hip-hop violin-viola duo, shakes up bias about which music is for whom. And if the youth market has missed the welcome mat, the Philadelphia Orchestra puts it out there once again Oct. 9 for its 11th annual free night for college students.

Classical music always could be all things to all listeners. It's getting there.

Ethel (Sept. 16, Bunker Hill Presbyterian Church, Sewell). With programs like this one — arrangements of Morricone's score to the 1986 film The Mission, Zuni and Hawaiian ritual sun chants, an adaptation of 12th-century composer Hildegard von Bingen — Ethel distinguishes itself as a string quartet original. The group takes the opening concert of Music at Bunker Hill, a lively series South Jerseyans should feel lucky to have. (856-494-6077,

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Philadelphia Orchestra Musicians Audience Appreciation Concerts (Sept. 17, various sites). A quartet of horns in Gray's Ferry, a wind octet in Chestnut Hill, a string trio in Glenside, and string quartets all over. Members of the Philadelphia Orchestra take themselves to 30 sites in the area between 9 a.m. and 9 p.m. in various solo and chamber music configurations to thank listeners for support with free performances. (

La voix humaine (Sept. 22-30, Theatre of Living Arts). In Poulenc's one-act, one-character 45-minute opera, the audience overhears a woman on the phone with her ex-lover going over their crumbled relationship. The piece has some of the composer's most touching and pained music. Performed here with piano (played by Christopher Allen) rather than orchestra, Opera Philadelphia augments Poulenc's La voix humaine for the O18 festival by preceding it with French art and cabaret songs. Soprano Patricia Racette sings Elle, the opera's only voice, and baritone Edward Nelson takes the songs in the prologue, suggesting here that he is the lover on the line later whose voice we never hear. It's better with orchestra, but a treat to hear nonetheless. (215-732-8400,

Opera on the Mall (Sept. 29, Independence Mall). We Shall Not Be Moved, premiered a year ago at Opera Philadelphia's O17 festival, gets a free outdoor broadcast. The opera — a collaboration of composer Daniel Bernard Roumain, librettist Marc Bamuthi Joseph, and director Bill T. Jones — uses the 1985 bombing of the MOVE compound as its animating force, but that's just the beginning of a work that follows a group of teens navigating social justice, violence, and other issues that seem to hover endlessly over American society. Viswa Subbaraman conducts. Not suggested for children under 14. (215-732-8400,

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Philadelphia Orchestra College Night (Oct. 9, Verizon Hall). College students get unlimited access to Philadelphia Orchestra concerts the entire season for $25 through the orchestra's eZseatU program, which kicks off with this concert led by Kensho Watanabe of Verdi's Overture to La forza del destino, the first movement of Dvořák's  Cello Concerto and the Suite from Stravinsky's The Firebird. The concert is free and includes a post-concert party in the Kimmel plaza. (215-893-1999,

Prokofiev's Romeo and Juliet (Oct. 11-21, Academy of Music). Should you close your eyes at the ballet? It's tempting in some repertoire. Prokofiev's score is probably the most vivid translation of Shakespeare's tale into sound, and a complete performance of it doesn't come around often. "Sumptuous" is how conductor Beatrice Jona Affron describes the work. She leads the company's orchestra in forthcoming performances that remind us of the critical role of the talent in the orchestra pit. (215-893-1999,

Jonathan Biss and Brentano Quartet (Oct. 23, Perelman Theater). Prefaced with works of Smetana and Janáček, the Dvořák Piano Quintet in A Major, Op. 81 is played by the dreamy combination of Biss and the Brentano. A lot of the emotion in this big piece comes from how the performers unspool certain excruciatingly beautiful harmonic changes — where they speed or slow, how they shape the dynamics — and it seems a good bet this particular group will handle itself with a highly evolved sense of nuance. (215-569-8080,

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Black Violin (Oct. 27, Merriam Theater). When they played World Cafe Live in 2015, this violin-viola duo impressed mightily as a fully integrated blend of hip-hop and classical string technique. Kev Marcus and Wil B come back to town, this time to the larger Merriam, with their rhythm-heavy energy, baroque ornaments, and Paganini-like licks. About their last show, the present critic wrote: "One frequent device was using a four- or five-note repeated figure for structure while variations bloomed, a latter-day Pachelbel canon. Other classical references were more specific, like the Shaker melody that also stirred Copland in Appalachian Spring. Wil B serenaded his viola — he calls her Tiffany — in a ballade." It's probably universal that no one can resist a viola named Tiffany. (215-893-1999,

Jordi Savall (Nov. 1, Annenberg Zellerbach Theatre). In a program called "The Routes of Slavery," the early-music specialist uses music from Mali, Brazil, Mexico, Peru, and the U.S. to tell the story of slavery and slaves, and the culture the enslaved brought with them. Their music and dance was "something that nobody could take away from them,"  Savall writes in notes for the program. Among the forces he assembles to realize this ignominious history in sound are percussion, oud, viol, shawm, sackbut, Spanish baroque harp, guitar, and vocals. (215-898-3900,

Imogen Cooper (Nov. 8, Perelman Theater). The exquisite pianist from London returns to the Philadelphia Chamber Music Society with a program that promises the good cheer of Haydn's Piano Sonata in C Major, Hob. XVI:50; a trembling mystery in Thomas Adès' Darknesse Visible; and a lifetime's worth of despair and euphoria in Beethoven's Piano Sonata in A flat Major, Op. 110 and the Schubert Piano Sonata in C Minor, D. 958. (215-569-8080,

Anthony Tommasini and the Indispensable Composers (Nov. 8, Free Library of Philadelphia). What makes a piece great? Who gets to decide? Is the concept of greatness even valid anymore? The chief classical music critic of the New York Times has assembled his own list of 17 indispensable composers — Puccini but not Ravel? — and you get to ask him why when he appears to discuss his new book, The Indispensable Composers: A Personal Guide, due out in early November. (215-567-4341,

Works of Julius Eastman and Peter Maxwell Davies (Nov. 10, Curtis Institute of Music). Curtis' 20/21 Ensemble, the group that plays under the school's new-music banner, pairs two fascinating works: Joy Boy, a 1974 woodwind quartet by Eastman, who graduated from Curtis in 1963; and Davies' Eight Songs for a Mad King, which was notably recorded by Eastman as vocalist not long after its 1969 premiere. (215-893-7902,

Barber Piano Concerto (Nov. 23 and 24, Verizon Hall). It's tough to play, easy on the ears, and terribly neglected. Which makes it just the perfect piece for pianist Garrick Ohlsson, who performs Barber's expansive and darkly lyrical score — premiered in 1962 as part of opening festivities for the orchestra hall at Lincoln Center — with the Philadelphia Orchestra and conductor Cristian Macelaru. (215-893-1999,

One Pianist, Three Violinists (Dec. 11, Perelman Theater). Mozart sonatas for violin and piano form the backbone of this concert featuring pianist Jeremy Denk with violinists Pamela Frank, Benjamin Beilman, and Stefan Jackiw. But these traditional pieces are set in an unusual context. The concert, which comes in three hour-long chunks with two 15-minute breaks, has been dubbed by Denk "A Feast of Mozart Violin Sonatas with Assorted Musical Sorbets."  But sorbet is more than a palate-cleanser when it includes movements by composers like Ravel, John Adams, Stravinsky, and Schubert. (215-569-8080,

Amahl and the Night Visitors (Dec. 13 and 15, Verizon Hall). It was the opera composed specifically for television, for children, and inspired by The Adoration of the Magi, the Bosch painting in the Metropolitan Museum of Art. Since its Christmas Eve premiere on NBC in 1951, Amahl and the Night Visitors has found its way into the hearts of several generations. But Menotti's small masterpiece has never been performed in full by the Philadelphia Orchestra until these performances led by Bramwell Tovey with singers from the Metropolitan Opera's Lindemann Young Artist Development Program. (215-893-1999,

Rodney Marsalis Philadelphia Big Brass Holiday Concert (Dec. 15, Annenberg Harold Prince Theatre). New Orleans Dixieland, baroque, jazzy arrangements of Christmas carols, a little Nutcracker, an Elvis tune ("Can't Help Falling in Love") — the Philadelphia trumpeter leads his seven-member brass ensemble in a program of mostly holiday music. One non-holiday work, but one well worth knowing, is the Harry James Trumpet Concerto, arranged here for brass quintet and drums with Marsalis taking the solo trumpet part. A piece of great swagger and daring (not to mention speed), it might be the most exhilarating 2½ minutes in the entire trumpet literature. Who better to take it on than Philadelphia's own Marsalis? (215-898-3900,