# Immersive Two-Channel Recordings Based on Personalized BRIRs and Their Applications in Industry
## 5 Methods for Creating 2-Channel Immersive Audio  
The general concept of 3D sound processing is based on creating sound effects which are able to mimic the way humans capture sound waves and determine spatial impressions based on them. Every stage, from the generation of the signal by the sound source, to the way the human ear filters acoustic waves and the technique with which the brain classifies them as specific sound impressions, is relevant here. Interpreting these stages and the elements that allow humans to experience immersion are the basis for understanding the idea of immersive sound. This is because in the real world, regardless of the method by which sound sources produce signals, it is the concrete distribution and interference of waves that allow a person to find themselves in a given three-dimensional space. Processing the recordings by basing the designed method on the physical properties of the sense of hearing and using directional information from the room where the measurements were made allows the creation of binaural audio with properties close to the actual signals heard by the listener at the recording site [41]. Well-replicated binaural audio can easily be compared to a real audio sensation experienced inside a multiple-loudspeaker setup system [42]. The technology for producing two-channel immersive recordings can be divided into several categories depending on how the recording is recorded, mixed, and processed. The main immersive techniques are those based on channels, objects, and ambisonics. Channel-based sound records sound sources in separate tracks, the most popular of which are the stereo standard (left and right sources), and the most recognizable arrangement is known as home theater, or 5.1 (left, right, center, two surround sources, and a subwoofer). Object-based sound is based on a specific number of channels, but combined with metadata that describe exactly where the sound should be in space. In contrast, higher-order ambisonics (HOA) treats the sound environment as a sphere that is directed to a focal point, or microphone position. Monophonic sound played through only one speaker or one channel does not contain any directional information, which means that in order to move the sound in space, one would have to physically move the speaker from which the signal is coming out. In the case of intensity stereophony, the matter is easier [43]. Thanks to the two channels used, the adjustment of the apparent sound source can be achieved by changing the relative volume of the signal in each speaker, which allows you to move the apparent sound sources in the space between the speakers. In other words, if the left channel is appropriately louder than the right, the sound, despite coming out of both speakers, appears to have its source on the left side of the stereo base, which accurately describes the idea of amplitude panning. Realistic 3D sound reproduced through headphones uses a number of processing techniques that mimic the way our ears process real sound sources--using interaural cues such as amplitude panning to give the sensation of changing source position. The most popular method, i.e., vector-based amplitude panning, generalized to three dimensions by [PERSON] [44], which translates a given set of signals to a chosen multi-loudspeaker environment, is still widely used when rendering binaural audio. The number of loudspeakers used in this method can vary, but the basis of the approach focuses on using any three chosen loudspeakers and forming a triangle. In this way, a so-called \"active triangle\" is created, and on its plane one can place the virtual sound source, thus digitally panning the sound amplitudes in the active region. There are known alternatives to these panning methods. For instance, VBIP (vector-based intensity panning), which uses intensity panning instead of amplitude panning; or DBAP (distance-based amplitude panning), which does not rely on listener position.