"Born in Buenos Aires, Argentina, in 1941, American composer and clarinet player Guillermo Gregorio has lived variously in Europe and the United States since 1986. Leading his Chicago-based trio and other ensembles, Gregorio has performed extensively, and his compositions have been recorded on numerous CDs by the Swiss label hatART and the American labels New World Records, Atavistic, and Nuscope, among others. His works have been played by noted New Music ensembles in the USA and Europe, among them Makrokosmos Ensemble (Switzerland) , Ensemble N_ER (EU), International Contemporary Ensemble (USA), Fonema Consort (USA), and the Maverick Ensemble (USA). In addition, as an instrumentalist, Gregorio has worked with many experimental and improvisational groups, including those that recorded the music of Cornelius Cardew, Anthony Braxton, and Philip Corner, among other contemporary composers (see discography for details).

As a composer and improviser, Gregorio has collaborated with Fred Lonberg-Holm, Ran Blake, Steffen Schleiermacher, Steve Swell, Jim O'Rourke, Ken Vandermark, Mats Gustaffson, Axel Dörner, Josh Abrams, Jeff Parker, Jason Adasiewicz, Carrie Biolo, George Graewe, Franz Koglmann, Thomas Lehn, Heiner Reinhardt, Le Quan Ninh, Akikazu Nakamura, Ab Baars, Sebi Tramontana, Mary Oliver, Klaus Koch, Gene Coleman, Enrique Gerardi, Paulo Alvares, Vinko Globokar, Makrokosmos Quartet, François Houl, and Stephen Dembski, among others.

He participated in the Argentine experimental music scene throughout the 1960s, '70s, and early '80s. His involvement with New Music included both composing and playing clarinet, saxophone and miscellaneous instruments in the Movimiento Música Más (Fluxus Group), the Experimental Group of Buenos Aires, and the Group of Contemporary Music of La Plata, featuring Fluxus events, multi-media spectacles, environmental pieces, and experimental concerts. Some of his earlier work in Argentina is available in the CD Guillermo Gregorio: Otra Música. Tape Music, Fluxus and Free Improvisation in Buenos Aires 1963-70 (Atavistic UMS/ALP209CD). After leaving Buenos Aires Gregorio had the opportunity to experience the European creative music scene of the middle '80s, i.e. the fruitful convergence of Free Jazz and 20th-century music and its interconnections with visual art. The interaction with composers and artists of that milieu constituted an indelible mark in his further explorations.

Gregorio-a visual artist himself-has frequently explored the intersection of visual and musical experience. His involvement in visual arts and design is a central influence in his music. In his series entitled "Madi Pieces" and "Coplanars" (1999-2005) Gregorio used Constructivist and geometrically generated ideas in scores ranging from conventionally notated material to graphic systems and open structures. In these compositions, a reinterpretation of the fundamental and structural concepts of Constructivism converges with the historical experiences of Argentinean Conceptualism, Fluxus, intermedia synthesis, and graphic realization. In January 2001, he founded the Madi Ensemble of Chicago, which performed original and historical scores that draw from the conceptual foundation of diverse Argentinean avant-garde currents. His scores related to that period have been exhibited in numerous shows at galleries and institutions, among them the Block Museum of Art (Northwestern University, Evanston, IL), Chelsea Museum of Art (NY), Kettle's Yard Gallery (University of Cambridge, UK), and Elastic, Sound & Vision Gallery (Chicago). Some of Gregorio's works belong to the permanent collections of the MADI Museum and Gallery in Dallas, Texas, and the Centre d'Art Geometrique MADI in Paris. His works have been published in Leonardo, Journal of the International Society for the Arts, Sciences and Technology, Notations 21 (Mark Batty Publisher), Noon Literary Annual, and other specialized publications. His series of pieces entitled "Otra Música" (2005 to the present), composed using conventional notation, focus on history and critical issues as well as syntactic aspects of texts and music. Still maintaining the openness of the works from the former period, the name of the series-"Otra Música"-refers to the title of a monthly column on experimental and avant-garde sounds that Gregorio wrote for a specialized magazine in Buenos Aires during the early '70s. Currently, Gregorio's interests are related to improvisation and "composition in real time" playing clarinet, in addition to the aforementioned compositions.

Gregorio has a degree in Architecture, and has worked as a graphic designer. As an educator he taught history and theory of architecture at the University of Buenos Aires, Argentina, and history of industrial design and visual communication at the University of La Plata, Argentina. In the USA he has taught history of 20th-century art and art appreciation at Purdue University North Central, Indiana, sound improvisation at the School of the Art Institute, Chicago, and worked as advisor of Grad Projects in the Sound Department of that School. At the present time Gregorio teaches History of Communication Design at Columbia College, Chicago."

"[..] Composer/bassist, Brandon A. Lopez, deemed "The Ubiquitous Free Improv Bass Ace" by the Village Voice and said to play with a "Bruising Physicality" by the Chicago reader.

He was born and raised in the splendors of Northwestern New Jersey, in the shadow of the (New York) city. It was there that he cultivated a taste for the left of center musics and subsequently, dug graves.

He's had the pleasures of working with many of the world's luminary weirdos. Here's a list: Nate Wooley, William Parker, Chris Corsano, Justice Yeldham, Weasel Walter, Peter Evans, Tyshawn Sorey, Gerald Cleaver, Ingrid Laubrock, Tom Rainey, Tony Malaby, Paul Lytton, Mette Rasmussen, Jooklo Duo, Michael Foster, Leila Bordreuil, Jaimie Branch, Joe Morris, Brandon Seabrook, Cactus Truck, John Dykeman, Daniel Carter, and many others.

He's currently leads a trio dubbed "The Mess", another one called the Brandon Lopez Trio, works as a soloist and is formerly/currently/latterly writing more and more music. He may play some it sometime soon (see "gigs").

He attended New England Conservatory."