His works have been commissioned or conducted by, among others, Claudio Abbado, Roberto Abbado, John Axelrod, Luciano Berio, Carlo Boccadoro, Riccardo Chailly, Myung Wun Chung, Ivan Fischer, Claire Gibault, Daniel Harding, Paavo Järvi, Neville Marriner, Zubin Metha, Riccardo Muti, Gianandrea Noseda, Antonio Pappano, Giuseppe Sinopoli.
He has worked with directors, actors, artists, and writers such as Daniele Abbado, Gae Aulenti, Patrice Chereau, Ermanno Olmi, Amos Oz, Renzo Piano,Toni Servillo.
Operatic works include: Girotondo, from Schnitzler (1982 Maggio Musicale Fiorentino festival), Il Viaggio, (1990, Teatro Comunale di Bologna), La Station thermale, (1993-95, Opéra National de Lyon), Les oiseaux de passage (1998, Opéra National de Lyon; 2001), Il letto della storia, (2003, Maggio Musicale Fiorentino), La madre del mostro (2007, Siena), Teneke (2007, Teatro alla Scala), Lo stesso mare (2011, Teatro Petruzzelli, Bari).
Instrumental compositions include: BriefeBüchners (1997, commissioned by C. Abbado, Berliner Festwochen); Dai calanchi di Sabbiuno (1997, commissioned by C. Abbado, Salzburg); Diario dello sdegno (2002, commissioned by the Filarmonica della Scala, conductor R. Muti); Tre Veglie (2000,commissioned by the Salzburger Festspiele, conductor I. Fischer); Terra comune (2002, commissioned by L. Berio for the opening of the Auditorium di Roma, by Renzo Piano, conductor Myung-Whun Chung,); La giusta armonia (2006, commissioned by the Salzburger Festspiele, conductor R. Muti,); Voci di notte (2006, conductor Zubin Metha, 2006, Maggio Fiorentino); Mare che fiumi accoglie (2007, conductor A. Pappano, Accademia Nazionale di Santa Cecilia); Prospero o dell’Armonia (a symphonic melologue, 2009, conductor R. Chailly, Filarmonica della Scala); Tagebuch der Empörung (2011, conductor R. Chailly, Lipsia, Gewandhaus Orchestra); D’un tratto nel folto del bosco, melologue, text by Amos Oz (2010); Notte italiana (2011, conductor David Atherton, London Sinfonietta); Soudain dans la forêt profonde, melologue, text by Amos Oz (2013-14, Paris, Comédie française, Salle Pleyel, CD released by the Ministère de l’Éducation Nationale and available also to French schools), Der Walddämon, (2015, R. Chailly, Lipsia, Gewandhaus Orchestra) Sull’acqua – sotto di noi il diluvio (2015, Orchestra Sinfonica di Milano Giuseppe Verdi ). In 2014 the MiTo Festival devoted to him – the first Italian so honoured – a three-concert monograph. In 2015 he supervised the Opéra en creation Atelier at the Festival of Aix-en-Provence, where in 2014 and 2015 were performed some of his works. His last opera, Lo specchio magico, based on a text by Aldo Nove, has been staged at Maggio Musicale Fiorentino on May 7 th, 2016. In the same year Vacchi has written Vencidos for the Festival Internacional Cervantino (Mexico), and Concerto per violino, Teatro Petruzzelli (Bari).
The first italian performance of La Giusta Armonia (Salzburger Festspiele 2006, Muti), conducted by Gianandrea Noseda, opened the 2016/17 season at Regio di Torino. On February 2018 is performed Eternapoli, with the Oscar Prize actor Toni Servillo, commissioned by Teatro S.Carlo (Neaples) and the Sonata n.1 for piano, at LAC, commissioned by Lugano Musica. In the same year Vacchi has written Concerto per violoncello, performed on October 31st ( Teatro Petruzzelli, Axelrod). On November 5th, was performed the second version of Concerto per violino with the new subtitle Natura naturans at Carnegie Hall, New York, with the Hungarian State Opera Orchestra conducted by B. Kocsár, violinist H. Nagao (winner at 2018 Carl Flesch Prize). Natura naturans was prewired performed also at Opera Budapest, on October, 12th. On February the Orchestra Verdi of Milan devoted to him four monographic concerts, with also the italian première of Natura naturans.
The first semester of 2020 will be busy with important performances. In March and April will be set up Eternapoli in Bologna and Milano, in March will be performed the première of a new TanzTheater at Teatro alla Scala, and in May a new opera at Maggio Musicale Fiorentino.
Prizes and nominations: Koussevitzky Prize in Composition (Tanglewood, USA, 1974);first prize in Concorso Gaudeamus (Netherland,1976); David di Donatello award for best soundtrack (Ermanno Olmi’s Il mestiere delle armi, Rome, 2002); Annual Lully Award 2002 for the best new work performed in the US (his Quartetto n°3); Premio Abbiati from the Associazione Nazionale Critici Musicali for the best new composition of the year (2003, Il letto della storia); Rdc Awards for the soundtrack of Gabrielle by Patrice Chéreau (2005); nominated for David di Donatello award for the best soundtrack, for Cento chiodi by Ermanno Olmi (Rome, 2007).
He holds a post-graduate course in Composition at the Scuola di Musica di Fiesole (Florence). Honorary member of Accademia Filarmonica Bolognese. Full member of Accademia Nazionale di Santa Cecilia.