Siedl/Cao is a Vienna-based composer-performer and sound artist group. They work in the field of contemporary electronic and instrumental music, music theatre and sound art. They are Cao Thanh Lan from Vietnam and Gregor Siedl from Austria. Siedl/Cao is one of 5 groups from Austria that received the award New Austrian Sound of Music 2018-2019 in the category Contemporary Music.

Their works have always been centered on the physical experience of sound and the inherent link between visual and audio elements. Hanoi traffic noise, clarinet, Vietnamese hubble bubble smoking pipe, daxophone, air pump, servo motors, precompressed spring, modular synthesizer, crackers, text-to-speech, marxophone, plastic plants, gaffer tape, infusion bags… are their sound sources for diverse works and performances for sites such as opera house, bowling alley, theatre, living room, university auditorium, vinyl shop, gallery, etc.

Siedler Cao

 Photo by Siedl/Cao

Duo works of Cao Thanh Lan and Gregor Siedl have been featured at international festivals and concert venues around the world, amongst others – Operadagen Rotterdam 2018, Musiktheatertagen Vienna 2018, Festival „Krieg singen“ im Haus der Kulturen der Welt Berlin, FIME – Festival Intern. de Musica Experimental Sao Paulo, Frischzelle Festival für Intermediale Performance Köln, Strom Festival Köln, Hanoi New Music Festival,  Festival Ankunft Neue Musik Berlin, Ftarri Tokyo, Nomart Osaka, WIM Zürich, CHELA Buenos Aires, National Opera Hanoi, Institut Francais Hanoi, etc. They have been touring in Europe, Iran, China, Taiwan, South Korea, Japan, Argentina, Brazil, Uruguay, Chile, Finland, Vietnam, Australia and Indonesia.

Duo Siedl/Cao has also given workshops on contemporary composition and improvisation at Monash University Melbourne, BoxHill Institute Melbourne, National University of Hsinchu Taiwan, Sungshin Women’s University Seoul, Mahidol University Bangkok, Äänen Lumo Helsinki, Universidad de La Serena Chile, Universidad de Montevideo Uruguay, Meridian Space Beijing, DOMDOM Center for experimental music Hanoi, etc.

For their projects and cooperations, they have received grants from Austrian Federal Chancellery (BKA) for Art and Culture, Austrian Cultural Forums in Tokyo, Brussels, Bangkok, Tehran, Hanoi and Warsaw, Cultural Department of Lower Austria, Austrian Embassies, ON-Neue Musik Cologne, Ministry for Culture in Nordrhein-Westfalen (MFKJKS-NRW), Rhein-Energie Stiftung.


Lan (first name) was born 1987 in Hanoi, Vietnam. She works in the fields of contemporary instrumental and electronic music, sound art and music theatre. She is the scholarship holder of Startstipendium 2018 from the Austrian Federal Chancellery. She was trained as a classical contemporary music pianist in Köln (with Pierre-Laurent Aimard) and Brussels, but recently she has focused mostly on her own compositions and sound installations, experimenting with modular synthesizers, prepared marxophone/zither, low-tech electronics, various objects, etc.

Active as a sound artist, improviser, composer in Berlin, Vienna and Cologne in many different projects, notably the composer-performer Duo Siedl/Cao – in collaboration with Gregor Siedl, she has been touring and giving workshops for contemporary music and improvisation in Europe, Japan, Brasil, China, Taiwan, South Korea, Argentina, Uruguay, Chile, Australia, Indonesia and Vietnam. Her works have been released on labels Impakt, Flaming Pines, Off Record, Acefalo Records and Syrphe. She has performed at experimental music festival such as Emittermicro Berlin, Flux Festival Berlin, Brechtfestival Augsburg, FIME festival for experimental music in Sao Paulo Brazil, Strom festival Cologne, Festival Frischzelle Cologne, Sonic Territories Vienna, etc.

As a guest pianist/performer of Kammerensemble Neue Musik Berlin (KNM Ensemble), she has performed at Ultraschall Festival Berlin, Musica Electronica Nova Wroclaw, Poesiefestival Berlin, etc. She has earned a wide range of solo and ensemble experience in contemporary music festivals namely Darmstadt Festival for new music, Festival Ircam Paris@Manifest and in festival academies such as Klangspuren – Ensemble Modern Frankfurt, Impuls Festival – Ensemble Klangforum Vienna, etc.


Gregor Siedl is currently based in Vienna, Austria. He is engaged in the field of sound art, experimental music theater and projects crossing genres and disciplines. His works could be seen as a by-product of an on-going process of self-recognition. His main interest is in exploration of sound and visuals, their form, their correlation and the way they are perceived. Recent projects have lead him to research ancient rituals, artificial intelligence, „natural radio“ emissions and DIY electronics. He is an active member of the experimental music scenes in Berlin, Vienna and Brussels.

He is a founding member of the long term collaboration Siedl/Cao, Junk Orbit, Parallel Asteroid, ZICLA, DOKO and  Osmosis Project. He has performed all over Europe, Middle-East, Asia and South-America at international music festivals and concert venues, such as: Festival Ankunft Neue Musik Berlin, HdKW Berlin, Festival Internacional de Musica Experimental Sao Paulo, Follow the sound Festival Antwerpen, Storm!-Festival, LeXGiornate Milan, Porgy&Bess Vienna, Ftarri Tokyo, EnvironmentZeroGauge Osaka, Dotolim Seoul, Estonian Academy of music, Improvised Music Co. Dublin and more.