Slovak Philharmonic Orders Four DAD AX24 Digital Audio Converters

Stanislav Benacka with NTP DAD AX24 digital audio converters: The AX24 is fully remote controllable via RS-422, USB or Ethernet

NTP reports the sale of four DAD AX24 digital audio converters to the Slovak Philharmonic symphony orchestra. These are for installation in a new control room being built at the Reduta concert hall and recording venue in Bratislava.

"The Reduta was regularly used by lot of recording companies including Chesky, Naxos, Opus and Slovart," states Richard Varkonda, Technical Manager of NTP's Bratislava-based reseller, Centron. "These companies will now be able to use the latest technology offered in house. The NTP AX24 converters are directly controlled from an Avid Euphonix System 5 Fusion console. They are connected via MADI to the console's core processor and to an Avid Pro Tools HDX2 System.

“Each of the four converters includes eight channels of microphone preamplification. Soundfield, DPA and Neuman microphones feed into the system. The microphone wiring to the converters is high quality star-quad multicore cable and is kept as short as possible to ensure efficient radio-frequency shielding.


The Reduta was purchased by the city of Bratislava in 1901 to be turned into a ‘palace of culture’. The original design called for an imitation of the Vienna Reduta but an alternative plan was developed and construction finally began in 1911. From 1913-1919 its facade was renovated to replicate a mixture of neo-Baroque, Rococo, and Art Nouveau styles, in an apparent attempt to evoke the period of Empress Maria Theresa. From 1916, concert performances were organised in the main 700-seat auditorium by the Bratislava Concert Association. The Reduta has been home to the Slovak Philharmonic since the early 1950s.

Designed for high quality music recording as well as mastering and monitoring in Digital eXtreme Definition (DXD) and Direct Stream Digital (DSD), the NTP DAD AX24 offers A/D and D/A conversion in PCM at up to 384 kHz sampling rate, DSD at 64 frame/s or 128 frame/s, and 352.8 kHz DXD. The optional microphone preamplifier incorporates analogue gain control in 3 dB steps as well as digital gain control with 0.25 dB precision. Dynamic range is between 118 and 121 dB. The preamplifier's equivalent noise floor is -130 dB.


The AX24 is fully remote controllable via RS-422, USB or Ethernet. Preamp parameters can be represented on the channel strip of industry-standard audio production consoles and workstations. MADI output is configurable to operate in loopthrough mode, connecting multiple converters to a single data output. The interface can be set to access any configuration of 64 MADI channels in blocks of eight consecutive channels. The AX24 can be synchronised to incoming AES 11, Word Clock, Super clock or video (PAL, NTSC, SECAM). An integral phase-locked-loop circuit is able to correct for minor variations in external sync timing.

Existing users of NTP DAD audio signal processors include Abbey Road Studios, Bauer Studios, Benny Andersson's RMV Studio, CMC Studios, Danish Radio, DEX Mastering, DPA Microphones, Echopark, Galaxy Studios, Hana Music Montreux, Helsinki Music Centre, Lindberg lyd, Master Touch, McGill University, Moscow Music Conservatory, NDR Hamburg, NHK, NRK, Real Sound, Royal Danish Opera House, Royal Opera London, Sidney Opera house, SK Works, SoundWorks/Jeff Sheridan, Spanish Radio, St Petersburg Philharmonic Orchestra, Stock Fish Records, Swedish Radio, Telarc International, Timbre Music, Ultimo Productions and the Warsaw National Philharmonic Orchestra.