Available methods for room-related sound presentation are introduced and evaluated. A focus is put on the synthesis side rather than on complete transmission systems. Different methods are compared using common, though quite general criteria. The methods selected for comparison are: Intensity Stereophony after Blumlein, vector-base amplitude panning (VBAP), 5.1-Surround and its discrete-channel derivatives, synthesis with spherical harmonics (Ambisonics, HOA), synthesis based on the boundary method, namely, wave-field synthesis (WFS), and binaural-cue selection methods (e.g., DiRAC). While VBAP, 5.1-Surround and other discrete-channel-based methods show a number of practical advantages, they do, in the end, not aim at authentic sound-field reproduction. The so-called holophonic methods that do so, particularly, HOA and WFS, have specific advantages and disadvantages which will be discussed. Yet, both methods are under continuous development, and a decision in favor of one of them should be taken from a strictly application-oriented point of view by considering relevant application-specific advantages and disadvantages in detail.

As the virtual reality (VR) market is growing at a fast pace, numerous users and producers are emerging with the hope to navigate VR towards mainstream adoption. Although most solutions focus on providing highresolution and high-quality videos, the acoustics in VR is as important as visual cues for maintaining consistency with the natural world. We therefore investigate one of the most important audio solutions for VR applications: ambisonics. Several VR producers such as Google, HTC, and Facebook support the ambisonic audio format. Binaural ambisonics builds a virtual loudspeaker array over a VR headset, providing immersive sound. The configuration of the virtual loudspeaker influences the listening perception, as has been widely discussed in the literature. However, few studies have investigated the influence of the orientation of the virtual loudspeaker array. That is, the same loudspeaker arrays with different orientations can produce different spatial effects. This paper introduces a VR audio technique with optimal design and proposes a dual-mode audio solution. Both an objective measurement and a subjective listening test show that the proposed solution effectively enhances spatial audio quality.

In virtual acoustics or artificial reverberation, impulse responses can be split so that direct and reflected components of the sound field are reproduced via separate loudspeakers. The authors had investigated the perceptual effect of angular separation of those components in commonly used 5.0 and 7.0 multichannel systems, with one and three sound sources respectively (Kleczkowski et al., 2015, J. Audio Eng. Soc. 63, 428-443). In that work, each of the front channels of the 7.0 system was fed with only one sound source. In this work a similar experiment is reported, but with phantom sound sources between the front loud- speakers. The perceptual advantage of separation was found to be more consistent than in the condition of discrete sound sources. The results were analysed both for pooled listeners and in three groups, according to experience. The advantage of separation was the highest in the group of experienced listeners.