Contemporary classical music isn't what it used to be.

Vast stretches of the 20th century were dedicated to writing music that sounded better in theory than in performance. Composers abandoned their audiences to curry favor with history and assert, "Who Cares If You Listen?" (the title of a famous mid-century article), while audiences learned to grit their teeth, call new works "interesting," and avoid all programs with names they didn't recognize.

Fortunately, starting in the 1980s, composers began to care more about living audiences than future ones and, more importantly, about whether audiences enjoyed their music. Humor and beauty returned, along with multicultural and multigenre borrowing.

In short, new music became fun again.

This weekend, the New Music Celebration offers a variety of new music, including a newly commissioned work called "Out of the Cradle Endlessly Rocking" by Denmark's foremost composer, Per Norgard.

The New Music Celebration is presented by Ebb & Flow Arts, a nonprofit organization for modern music and multimedia events. The only such organization in Hawai'i, Ebb & Flow Arts was founded in 1999 by composer/pianist Robert Pollock "to break down the barriers between the arts and form a bridge between artistic expressions and cultures."

Monday's concert is free, making it a perfect opportunity for those on O'ahu who are newcomers to contemporary classical music, and Tuesday offers a chance to hear more, along with a lecture by Norgard.

Born in 1932, Norgard has grappled with the complex journey classical music has traveled over the past 75 years. He was a young man when Milton Babbitt wrote "Who Cares If You Listen?" and he experimented with a variety of techniques and styles before developing a serial approach he called the "infinity series," based on the symmetry of nature. In the 1980s, he explored chaos and fragmentation; and then, more recently, he turned to layering rhythms and lines.

During his lifetime, Norgard has been both panned and hailed, received awards for, and endured protests against, his music.

Other featured composers include George Theophilus Walker, the first African-American composer to earn the Pulitzer Prize in Music, and Astor Piazzolla of Argentina, who studied with the legendary composition teacher Nadia Boulanger.

As Piazzolla related, "When I met (Boulanger), I showed her my kilos of symphonies and sonatas. She started to read them and suddenly came out with a horrible sentence: 'It's very well written.' And stopped, with a big period, round like a soccer ball.

"After a long while, she said, 'Here you are like Stravinsky, like Bartok, like Ravel, but you know what happens? I can't find Piazzolla in this.' And she began to investigate my private life: what I did, what I did and did not play, if I was single, married, or living with someone — she was like an FBI agent! And I was very ashamed to tell her that I was a tango musician ... (and played in a cabaret). ...

"Finally, I confessed, and she asked me to play some bars of a tango of my own. She suddenly opened her eyes, took my hand and told me: 'You idiot, that's Piazzolla!' And I took all the music I composed, 10 years of my life, and sent it to hell in two seconds."

New-music concerts allow listeners to hear new voices, new ideas and to decide — unbiased by history, what one "should" like, and whether the music is "great" — what they do and do not like.

It is as true today as it was in Mozart's day that only a tiny percentage of the music composed each year endures in the repertoire, but the purpose of new music is not to create history but to touch the hearts, minds, and souls of those who listen.