This shell-like concrete structure with triangular slices is an auditorium designed by Luxembourg studio Valentiny HVP Architects for an annual music festival in the Brazilian town of Trancoso (+ slideshow).

Nearly complete, the Teatro Mozarteum Brasileiro will provide a performance venue for the Música em Trancoso, a week-long music festival that takes place every March in the popular beach town on Brazil's Bahia coast.

The festival was founded by architect François Valentiny of Valentiny HVP Architects, with partners Sabine Lovatelli, Reinold Geiger and Carlos Eduardo Bittencourt. Now in its third year, the event will have its own permanent auditorium capable of hosting indoor and outdoor audiences.

Two large triangular openings in the curved concrete facade provide entrances for the two separate seating areas. These are positioned alongside one other and can accommodate up to 1100 people each.

A neighbouring structure, known as the facilities building, houses ancillary spaces, including rehearsal rooms, meeting areas and a bar.

The triangular windows of this building are decorated with engraved bronze panels, created by Brazilian artist Maria Bonomi.

"The engravings refer to both the local nature with its impressive cliffs and the birth of the Brazilian nation," said the studio.

Photography is by Jean de Matteis and Valentiny HVP Architects.

Here's a project description from Valentiny HVP Architects:

Música in Trancoso Festival

The Música em Trancoso 2014 Festival, to be held March 15th through March 22nd, the third grand event that celebrates arts, promotes education and transforms music as a tool for social integration, announces this year’s wide range of activities.

After two years of meticulous planning, the first Música em Trancoso Festival was held in March 2012. It was the result of the dream of four friends, music lovers and social activists who wanted to create an event to bring together young musicians and established artists while at the same time promoting the natural beauty of the Trancoso region and stimulating economic and social development.

The Festival's critical and popular success was immediate and can be measured by the outstanding performances of more than 200 musicians before 10,000 spectators.

Every year for eight days in a series of free concerts and accompanying musical events between Carnival and Easter, the village of Trancoso welcomes performers and soloists of international recognition in classical music as well as the greatest names in Brazilian popular music.

Its founders are Sabine Lovatelli, president of Mozarteum Brasileiro, one of the most acclaimed associations devoted to the diffusion of classical music in Brazil; Reinold Geiger, president of the L'Occitane group; Carlos Eduardo Bittencourt, entrepreneur from Trancoso, Bahia; and the Luxembourgish architect François Valentiny, internationally known for designing theatres and cultural venues.

Música em Trancoso has three interrelated activities, which take place throughout the event:

- Performances at the Teatro Mozarteum Brasileiro.

- Masterclasses in the "Facilities" building, adjoining the theatre

- Music Initiation Classes for children and teens from public schools in the Trancoso and Arraial d’Ajuda region

The Mozarteum Brasileiro Theatre

From the bold design by architect François Valentiny, the Mozarteum Brasileiro Theatre has two different overlapped audiences, one indoor and one outdoor, each with 1,100 seats.

Design as well as acoustics of the theatre, are in charge of Valentiny architects, Luxemburg, known for their designs of cultural venues including the Concert Hall Saarbrücken (Germany), the House of Mozart – Kleines Festspielhaus Salzburg (Austria) and the Luxemburg Pavilion Expo 2010 in Shanghai.

In the future, the theatre will house various cultural and socio-educational activities, becoming a permanent centre of cultural production.

The Mozarteum Brasileiro Theatre also includes an annex, "The Facilities" building, with eight rehearsal rooms, spacious bar and meeting rooms. With a design which contrasts curves with triangular openings, totally integrated with the natural environment of Trancoso, the building brings imposing panels, etched in bronze, from the renowned Brazilian artist Maria Bonomi. The engravings refer to both the local nature with its impressive cliffs and the birth of the Brazilian nation.