"One of the reasons why I like this initiative so much is that we are all in it together. There are no pre-established roles. It's a lot like the music itself," says Bechir Saade, a clarinet and ney player who is one of nearly 20 musicians participating in the sixth edition of the Irtijal Festival of Free Improvised and Experimental Music, which is being held in Beirut this week.

"The organization is done by the musicians themselves in an ad hoc manner sometimes, but it's working," says Saade. "At the end of the day I think we're creating something sustainable. The structure is getting bigger and more serious."

Irtijal (which translates roughly as "improvisation") is organized by the Lebanese Association for Free Improvised Music (MILL). It began with a prototypical mini-festival in 2000. MILL's founders - trumpet player Mazen Kerbaj, guitarist Sharif Sehnaoui and his partner, saxophonist Christine Sehnaoui - got together for just one night of cacophonous noise at Stike's in Hazmieh.

Six years later, Irtijal is unfolding over the course of five nights at Masrah al-Madina and the Goethe Institute. There are musicians flying in from Sweden, New Zealand, Switzerland, Italy, the Netherlands, France, Germany and the United States. Among the highlights will be performances by American percussionist Jason Khan, the multinational Blast Quartet and a live collaboration between German trumpet player Axel Dorner and American percussionist Michael Zerang.

Over the years, Irtijal's initial local trio has also burgeoned into a solid group of eight, including Saade, Raed Yassin on double bass, Jassem Hindi on electro-acoustics and Charbel Haber on guitar and his laptop. A number of them have lately formed the Mukhtabar ("laboratory" in Arabic) Ensemble.

Kerbaj and the Sehnaouis have an ongoing project called Rouba3i (a stylized version of "quartet" in Arabic), in which they always play with one new musician, who adds a wild card to the trio. The year's festival is the setting for Rouba3i's ninth and 10th such experiments, with Khan and Italian electro-acoustic drummer Fabrizio Spera.

In addition to some 20 different concerts, Irtijal is also hosting workshops with Zerang and Dorner. Many of the musicians will be recording their work while they are here, and two independent labels that have grown up around the festival - Kerbaj's Maslakh ("slaughterhouse" in Arabic) Records  and Haber's Those Kids Must Choke Records - are planning a set of joint compilations documenting the festival's history so far.

Irtijal is also going multidisciplinary. Zerang is working with local actors to develop a piece of "physical, visual theater." On April 15, Christine Sehnaoui is presenting a program of experimental videos called "Toupie Tournante: Resistance(s)," with screenings by artists from all over the Arab world and the diaspora, including Mounir Fatmi, Jayce Salloum, Zoulikha Bouabdellah, Wael Noureddine and Taysir Batniji. The point here is to explore the intersections and overlapping interests that exist between experimental music and experimental art or, as Hindi succinctly puts it, "the plasticity of sounds and the plasticity of images."

This year marks the first time Irtijal is taking place in the spring instead of the summer.

The reasons are primarily logistical. The organizers realize that air travel is cheaper this time of year. But the move also pulls them out of the packed summer festival circuit, and out of competition with the bigger, better-funded institutions that are Baalbek, Beiteddine and Byblos. If summer is for music festivals and fall is for film festivals in Lebanon, the spring season remains relatively free. Irtijal has essentially planted itself into the calendar with room to breath and room to grow.

All that said, Irtijal still has one major, formidable obstacle to overcome, which is convincing a local public to turn up, tune in and listen.