# Creating a Remote Choir Performance Recording Based on an Ambisonic Approach
## 2 Performing Remote Concerts
First-order ambisonic audio can only be used when uploading a finished recording [31]. Another platform, Facebook, supports live streaming with 360\({}^{\circ}\) images and first-order ambisonics [32], while the uploaded finished recording can contain second-order ambisonic sound [32; 33]. There is also a completely new platform focused on the presentation of content with spherical video and audio mixed in higher-order ambisonics called \"HOAST\" [34]. It is worth noting, however, that all of these technologies are not strictly about connecting musicians located in separate locations but rather about virtually mapping the stage with musicians for audiences located in distant concert halls. The stumbling block to full NMP continues to be latency on the order of 25 ms, particularly when using popular consumer connections such as ADSL. Only 5G technology offers hope to overcome these difficulties [35]. Therefore, remote musical performances are present in the form of recordings created in postproduction based on recordings of individual parts of songs sent by their performers. The best known are the achievements of composer [PERSON], who has been organizing concerts of the so-called virtual choir since 2009 [36]. Six editions of these sessions have been created, and thousands of people from all over the world have participated in each of them. Especially the last one, the 6 th edition, received significantly more interest, which was due to the fact that it took place in the spring of 2020, when COVID-19 was considered a global pandemic. At that time, musicians, in particular, began to investigate alternative, remote performance methods; the demand for such solutions can be confirmed by the fact that [PERSON]'s Virtual Chorus, sixth edition, attracted over 40,000 choristers from 145 countries. Nevertheless, no remotely performed recording has been spatialized using ambisonics. It was not until the COVID-19 pandemic that the first such productions were made [37; 38; 39; 40; 41]. One of them is [PERSON]'s piece, Sicut Cervus, performed by the Academic Choir of the Gdansk University of Technology in a pioneering recording, called \"Virtual Cathedral\" [42]. A discussion of the production of this recording will be presented in the following sections. It should be pointed out that investigations concerning performing remotely in the context of quality of experience (QoE) [43] are rare or non-existent in the literature. They appear mainly in identifying problems in the learning environment [44; 45], where a student's attention or collaboration is essential. In contrast, such remote strategies are well-adapted to medical applications, where they are especially used for surgical planning with simulation instruments, including VR (Virtual Reality) and AR (Augmented Reality), are used on a daily basis [46]. Moreover, checking audio-visual quality often employs QoE methodology [47; 48; 49; 50; 51]. When discussing QoE, one should consider at least several factors that quality encompasses. These are overall perception, acceptability, presence, immersion, to name a few [52]. [PERSON] et al. measured some of these aspects by employing a VR headset with an eye tracker [50]. It is known that one of the parameters evaluating artists' performances, whether a choir or an orchestra, is called 'ensemble'. Moreover, the conductor guides all the performers and strengthens the bond between the artists and the audience. When artists perform remotely and separately, such an ambiance may not be present. So, a question arises about how to measure QoE in such a case. In many studies, head-/gaze-/eye-tracking technology,a video-based eye-tracking relying on locating pupil center to measure gaze, is a highly exploited technology in the context of QoE and objectivization of audio-visual experiments and subjective tests [44; 49; 51; 53; 54; 55; 56; 57], so we decided to apply an eye-tracker to observe the choristers' performance.