# Creating a Remote Choir Performance Recording Based on an Ambisonic Approach
## 2 Performing Remote Concerts  
It is worth mentioning that the first implementations of remote concerts were applied to academic networks, and an experimental concert with artists (AMFC Vocal Consort, Schola Cantorum Gedanensis, and Capella Cracoviensis) from different cities in Poland took place in 2001 [14]. On the occasion of the 10 th anniversary of the Internet in Poland, the Research and Academic Computer Network (NASK) and the Interdisciplinary Centre for Mathematical and Computational Modelling at the University of Warsaw (ICM), in collaboration with the Fryderyk Chopin Academy of Music, organized an experimental Internet concert performed in three cities (Warsaw, Gdansk, and Cracow) using Internet connectivity on 14 September 2001. The concert included the world premiere of [PERSON]'s piece Ad Laudes, written especially for the 10 th anniversary of the Internet, but at the same time to commemorate the victims of the terrorist attacks of 11 September 2001. The sound and image were transmitted via the Internet via the POL-34 network. The musicians saw each other on monitors while the audience gathered in the three cities watched the concert on plasma screens. Simultaneously, the broadcast was carried out by all public Polish Television regional channels. The artistic direction was assumed by the conductor [PERSON] [14]. The technical layer of the network connection is also worth mentioning. The channel bitrate was set to 15 Mbps. The video signal was encoded in the MJPEG standard, which ensured minimal delay in transmission--the most critical factor for the success of the experiment. Realistically, delays of about 180 ms were obtained between the cities in one direction, of which about 70 ms were consumed by encoding and decoding the signal. In streaming, however, the spatial layer of sound sources has only recently become technically available. Binaural and ambisonic techniques as tools for localizing remote audio sources have settled fastest in teleconferencing applications [15; 16; 17; 18; 19; 20]. We should mention the AltSpaceVR platform [21], in which teleconference meetings, demonstrations, presentations, classes, or social gatherings can be conducted; the audio of all objects in the platform is subject to auralization and binauralization. In the case of the so-called Networked/Remote Music Performance (NMP) [22], successful attempts have already been made to transmit multichannel audio [23; 24; 25; 26]. Transmissions using ambisonics have also been performed [27]. Ambisonics can be thought of as a transmission format for creating 3D spatial audio. It is based on the representation of the sound field by decomposing it into orthonormal basis functions--called \"spherical harmonics\". This representation enables a flexible production process that is independent of the target playback system (speaker system or headphones). The concert, \"PURE Ambisonics Concert & the Night of Ambisonics\", organized in the framework of an international conference (3 rd International Conference on Spatial Audio) in Graz in September 2015, was undoubtedly one of the pioneering events of its kind [28; 29; 30]. During the concert evening, an ambisonic format was used to distribute the concert to different venues and broadcast it in real-time (including the following radio transmissions: nationwide terrestrial and satellite radio broadcasts). The concert hall was prepared for recording and transmission using a 23-channel speaker system, a 5.1 mix, and a binaural mix for headphone listening. The concert from the ICSA 2015 conference encouraged the authors of this idea to conduct a live 3D concert with [PERSON] in July 2016, including real-time spatial effects and transmission to another interior [28]. However, all of these presentations were experimental. To become a standard for recording or broadcasting, they must be implemented on commonly used platforms. For example, on the YouTube platform, only live streaming with 360\({}^{\circ}\) video alone is possible (sound must be in stereo).