"After 30 years of working in the restaurant of the Royal Conservatory of Music of Liège (BE), Andrée who had served us so many meals had never played a single note of music! Students, staff of the Conservatory, friends, neighbors and teachers, after being given 7 years of music theory in 7 minutes, the One Day Orchestra takes place in the Great Hall of the Conservatory for a unique concert. Andrée who has never touched an instrument in his whole life plays the Harp, the majestic harp of the Liège Philharmonic Orchestra."

Baudouin de Jaer is at the initiative and then cofounded 3 areas of musical / artistic creations open to all and with or without prior artistic knowledge: Back To Normal - The Cirque of Sounds - The House of Creation (later House of the creation cultural center of Brussels North). In 2009 he continued his journey by proposing the concept-space Orchestra of a Day: a traveling space whose beginners and non beginners musicians (provided exceptionally at the request of the children) change with the city or the country. The parameters of each Orchestra of a day are always different: place of reception, type of place, musicians, partitions, duration of the meeting, scenography, planning of the day, partitions, improvisations, composition, direction, repercussion, instruments and sound object, purpose, collaboration or not with other arts, preparation, communication. Each orchestra is tailor-made with the venue according to its desires, needs, objectives and missions. Open to all means that it is open to everyone, professional, person in situation or not of handicap, solist, beginner, musician of a day having never played. In this space the social component does not exist and the creation of the day is a momentarily most natural creation in the sense that the tradition of levels - blockages and preferences, is momentarily put aside to valorize an extraction of ideas musical structures, sound structures and common reflections towards modes of presentation appropriate to each situation.

Some one-day orchestra takes more preparation time than others. In some cases, compositions are written for the occasion, either by Baudouin de Jaer or by a composition bureau which meets the day before. There is also the Opera of a day and the musical CAMPUS of a day. The orchestras have already varied between 12 and 100 people in one day. It's space at all possible. While creating, the idea is to transmit 30 years of experience acquired in the TRIPTIK Back To Normal - Cirques des Sons - House of creation in one day, and in fast speed. Sometimes the organizer prefers to take the orchestra on a trip and to do this Baudouin de Jaer prepares everything in advance before the crossing. This is the opposite of transmission in slowness. The musicians of a day will then see the day under the angle of a musical awakening of a day. One-Day Orchestras have already been performed in 1991 Liège, Belgium, France, Switzerland, Poland, Slovenia - 1993 Brussels, Slovenia - 1995 National Theater - 1999 Brittany-Guérande - Rennes - Pedagogical Department of La Monnaie - 2000 Halles de Schaerbeek - 2001 Brussels Pocket Theater - 2003 Jeonju Sori Festival South Korea-2004 Palestine - Brussels Pocket Theater - 2005 BOZAR - Seoul South Korea Park Olympic Museum, Brussels Balsamine Theater - 2006 Jazz Marathon Grand-Place in Brussels - 2007 Brussels Creative House, Mons PASS - 2008 CEC Hesse de Vielsam - 2008-2009 Brussels Flagey Tour Jacques Frank Cultural Center, Balsamine Theater, St Gilles Music Academy, EEC Music Circle, European Parliament Open House, Varia 100 Musicians Theater, Espace Senghor, Liège, Mons Theater, Malmedy - 2010 Ferme du Biérau of LLN, Brussels ISFSC, Komische Oper of Berlin / RESEO - 2011 Halles de Schaerbeek, Royal Music Conservatory of Liège, CC Ottignies LLN, House of Creation, Lille Opera, Opera of Como and Milan - 2012 CC La Louvière , Conservatory and CAN of Neuchâtel, Charleroi, Molembeek canal festival, Jette - 2013 CC Arlon, Symphony Orchestra of Besançon, Lille Métropole, Nalja Seoul - 2014 Marchin, Engis, Contemporary Resonance Festival of Bourg-en-Bresse, House of Creation CC Brussels North, School GBS Wemmel - 2015 Resonance Contemporary Festival of Bourg-en-Bresse, BOZAR 100 young people for freedom of expression / Caritas International - House of Creation - 2016 Cultural Center of NA MUR, REMUA - 2017 Liège OPERA + Liège City Mirror / OPRL, BXL Central of Contemporary Art, BXL Theater 140 - 2018 BXL Central of Contemporary Art, Holland, FJM, Imola Center (Bologna) - 2019 St Sébastien sur Loire (NANTES)