Peer feedback has been widely recognized as an effective pedagogical strategy, yet empirical research in choral singing contexts remains limited. Existing studies have largely emphasized the cognitive features of feedback, particularly in relation to learning outcomes for feedback providers. This study investigates whether affective features of peer feedback play a stronger role in predicting learning gains for feedback receivers in a choral singing context. Participants were 44 undergraduate students (aged 18-22) enrolled in a university-wide elective course on music theory and choral singing at a normal university in China. Using a mixed-methods design, peer feedback comments and singing performance data were collected across four assignments. Written peer feedback comments (n = 784 meaningful units) were coded by two trained raters for identification, explanation, suggestion, praise, and overall feedback tone, with strong inter-rater reliability (Cohen’s κ range = .83-.91). Singing performance was independently evaluated by expert raters using a multi-dimensional rubric addressing both technical and expressive aspects. In addition, semi-structured interviews were conducted to capture students’ perceptions of giving and receiving peer feedback. To examine learning gains over time, regression analyses were conducted predicting subsequent singing performance while controlling for prior performance. Results showed that while the distribution of cognitive feedback features resembled patterns reported in prior peer feedback research, the accuracy of feedback was lower than that typically observed in traditional academic contexts. Importantly, among all coded features, only the tone of received feedback significantly predicted subsequent improvements in singing performance, with positively toned feedback associated with greater gains. These findings suggest that in choral singing environments, where emotional engagement and sustained participation are central to learning, the socio-relational qualities of peer feedback may outweigh cognitive features in driving performance development. The study highlights the importance of contextual moderators in peer feedback theory and underscores the need for educators to prioritize supportive feedback climates.