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KV2 powered Czech Philharmonic Open Air concert in Prague


The Czech Philharmonic recently closed its 119th season with an Open Air concert in Prague, followed by a standing ovation from more than 6,500 listeners. For the third successive year a KV2 Audio system provided this unprecedented experience with the highest possible audio quality and delivery.

At the picturesque Hradčany Square near the Prague Castle, the orchestra with Jiří Bělohlávek was joined by the piano virtuoso Kirill Gerstein, as well as Children's Choir Čhavorenge led by the singer Ida Kelarová.

The evening started with Bedřich Smetana's Tábor to commemorate 600 years since the burning of John Hus. This was immediately followed by famous Russian pianist Kirill Gerstein playing Rhapsody in Blue by George Gershwin and Rhapsody on a Theme of Paganini, Op. 43 by Sergei Rachmaninoff. The programme was accompanied by two parts of Aaron Copland's ballet Rodeo (3. Saturday Night Waltz and 4. Hoe Down) and voices of Čhavorenge's choir led by Ida Kelarová concluded the concert with a selection of Roma's songs.

For the last three years KV2 Audio have provided a complete sound system to to guarantee an uncompromising experience, leaving the audience overwhelmed at this classical event. KV2's systems are perfect for classical music as they add absolutely no coloration to the natural timbre and character of each individual instrument or vocal, with listeners commenting that they felt as if the sound came from the space on stage, not boxes between them and orchestra. One of the most dramatic moments of the evening, demonstrating the powerful dynamics of the system, came when the very silent bridge of Smetana's Tábor contrasted with powerful kettledrum passages.

The audience also witnessed a breathtaking performance of Kirill Gerstein playing unique Petrof's piano with the special 'active piano lid' designed by KV2's chief engineer George Krampera. As George explained "It has been always challenging to install microphones into a concert piano, choosing a placement where the transmission of the signal doesn't lose its quality, or become badly affected by reflections from the piano lid". George Krampera's system integrates the microphones within the wooden lid, adding a dedicated electronics and VHD (Very High Definition) pre-amplifier with built in line drivers into the piano body. This approach provides a perfect balance of Left, Right and Bass strings at the mixing console ensuring that the sound of the piano is very consistent, always present and doesn't get lost, even in the most complicated passages.

KV2's PA system was divided into three parts.

1. Main stereo LR (main listening area in front of the podium) per side

  • 3x VHD2.16 subwoofers
  • 1x VHD2.0  hi/mid/mid-bass cabinet
  • 1x VHD1.0 hi/mid/mid-bass downfill

Supported on the ground per sides with 2x VHD1.21 and powered by 2x VHD2000 and 1x VHD3200
Mono front filling of the first few rows was provided by 2x ESM26 powered by ESP2000 and delayed by an SDD3 unit. 

2. Supplementary delay stereo LR (area behind the sound direction) per side

  • 2x ESR215 hi/mid/bass fullrange flyed on delay towers
  • Powered by ESR3000 and delayed by SDD3 unit

3. Supplementary delay mono (front area of the park behind the podium) per side

  • 2x EX12 hi/mid/mid-bass fullrange set on pole mounts and delayed through SDD3


  • monitoring for compere - 1x EX10
  • monitoring for orchestra - 2x EX10 on pole mounts

Other details:

  • Mixing console - modified Audient AZTEC 32-channels
  • Individual mic channels amplified up to link level (due to the length of wiring into mixing console) through SD8 stage driver
  • Microphones: AKG C414, AKG C451, SHURE KSM9, Sennheiser MD421, Neumann U87
  • Active piano cover with Audio-Technica mics

Photo credits: Michal Kobrle, Petra Hajská


Head Office KV2 Audio International spol. s r.o.
Nádražní 936
Milevsko 399 01
Czech Republic

VAT: CZ26051591
Phone: +420 383 809 320 (English)
E-mail: info@kv2audio.com


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