Spatial audio technology can significantly enhance the immersive experience of virtual reality (VR), yet its perceptual effects across various virtual scenes remain underexplored. In this study, we propose a unified spatial audio system that extracts spatial information from panoramic videos, applies the Vector Base Amplitude Panning (VBAP) algorithm for multichannel audio mixing, and improves auditory quality through frequency equalization and dynamic range compression. Using this system, we evaluated the impact of different spatial audio elements on user immersion in open and enclosed VR environments. The results reveal notable scene-dependent effects: Although the degree of influence varied across scenarios, complete spatial audio configurations consistently received the highest user ratings. In dynamic, multi-source scenarios such as concerts, the absence of spatial localization significantly impaired directional perception, directly reducing immersion. Environmental sounds contributed significantly to perceived realism in small, enclosed indoor spaces but had a relatively minor impact in larger or outdoor settings. Spatial reverberation enhanced auditory richness in most scenes, and its absence led to a noticeable drop in immersion, especially in enclosed indoor spaces like concert halls. In contrast, its effect was diminished in concert scenarios, likely due to masking by strong direct sound sources, such as live music. These findings highlight the importance of context-aware spatial audio design, emphasizing that immersive experiences can be optimized by adapting spatial audio elements to the characteristics of specific virtual environments.