Background: Vocal music is a multifaceted subject, as students not only need to master skills but also to appreciate and critically interpret the singing process. Conventional vocal music learning methods emphasise practice and feedback, but deeper learning often stems from reflective assessment, especially when students adopt the perspective of an evaluator, as this role enhances their understanding of evaluative criteria and sharpens their performance focus. However, students rarely have access to authentic evaluation experiences in real-world settings since they are typically positioned as performers rather than evaluators. Objective: To address this challenge, this study introduces the spherical video-based virtual reality (SVVR) technology that enables students to play the role of vocal evaluators in a highly realistic and immersive context. Nevertheless, without appropriate support, the immersive nature of virtual environments may lead learners to become disoriented and overlook knowledge acquisition. Thus, a structural scaffolding of Evaluation-Explanation-Comparison was proposed for SVVR to support effective reflection and assessment. Method: A quasi-experimental study was conducted to investigate the effectiveness of the approach with a total of 28 students recruited as the experimental group, while 27 students were in the control group. Results and Conclusions: The results showed that the method significantly improved students' vocal music appreciation scores and singing skills, as well as their learning motivation, self-efficacy and critical thinking. Furthermore, this study explored learners' feelings and experiences under different methods through interview analyses. This innovative approach offers a creative pathway for vocal music education, highlighting the potential of leveraging technology and new instructional frameworks to promote students' assessment and enhance learning outcomes.