Modern ‘ship in a bottle’ concert hall opening inside a historical spa in Czechia

Prague is not the only Czech city that will be getting a new concert hall. The West Bohemian spa town Karlovy Vary will soon have a new venue in the middle of Císařský lázně, a neo-Renaissance building that dates to 1895.

The design by Petr Hájek Architekti will stand on six steel legs in the courtyard in the spa building’s interior, not directly touching the culturally protected building. All the interventions will be reversible so they can be easily replaced by new technologies in the future.

The ceremonial reopening of the renovated Císařský lázně will take place on June 17, 2023.

The Karlovy Vary Symphony Orchestra will use the new hall for its concerts, and theatrical performances will also take place. Thanks to the adjustable height, the auditorium can quickly be transformed into a conference space or ballroom that requires a flat floor.

The hall will be complemented by multimedia exhibits presenting the history of spas in a global and local context, a cafe, an information center, and a research room.

Císařský lázně (Imperial Spa) has been protected as a national cultural monument since 2010, so creating the addition was a difficult technical task.

The individual parts were inserted into it through an opening in the roof and assembled into a compact whole on the spot.

Architect Petr Hájek compared the process to building a ship in a bottle. “First, we had to make everything and assemble it in the hall in order to know that nothing was missing. Then everything had to be numbered, disassembled, and reassembled in the atrium of the building. It was a painstaking job,” he said.

All necessary audiovisual, scenic, and acoustic technologies are embedded in the structure. The only connections to the historical building are for electricity.

The color of the built-in structure is a very striking shade of red. “Our proposal is based on great respect for the historical space. We knew from the beginning that we would tiptoe around the original building. We want to carefully complement it, enrich it, but not disturb it,” Hájek said.

He compared the new theater to a red crab that has space for music in its arms. “The selected red color is archetypal with many other connections. It represents excitement and emotions, but also the machine aesthetics of the end of the 19th century," Hájek said.

Karlovy Vary’s Governor Petr Kulhánek said the proposal respects the needs of monument protection while fulfilling the acoustic, operational, and technical requirements for a mixed-use concert space.

“Císařský lázně will open to visitors in June after an overall demanding renovation, for which they have been waiting for more than 20 years,” Kulhánek said.

The acoustic properties of the built-in hall are also unique. The stage is equipped with a sliding acoustic wall and adjustable rotating panels that can adapt the space to various sound requirements.

Each side of the rotating triangles in the ceiling has a different function. One absorbs the sound, another reflects it and the third scatters it. This creates ideal conditions for performers and various forms of programs.

Classic audiovisual technologies are installed so as not to disturb the overall impression. An organ, which will be installed later, is also an integral part of the design.

This is not the only new concert hall planned for a historical building in Czechia. An addition to the historical Invalidovna complex in Prague 8 is also planned as a home for the home of the Prague Philharmonic Choir, among other tenants. The design for that is also by Petr Hájek Architekti.

A building permit was issued earlier this month for a modern concert hall in Ostrava. A new, modern addition will be added to the existing Dům kultury (Culture Center). It is designed by Steven Holl Architects with Architecture Acts and Nagata Acoustics.

The largest project, though, is for the Vltava Philharmonic Hall, a completely new structure planned for Prague 7’s waterfront. It is designed by Danish studio Bjarke Ingels Group (BIG).