Quantum-Enhanced Analysis and Grading of Vocal Performance

We present QuantumMelody, a hybrid quantum-classical method for objective singing assessment. Grouped vocal features (pitch stability, dynamics, timbre) are encoded into a small simulated quantum circuit; all nine qubits are initialized with a Hadamard on each qubit and then receive Rx, Ry, and Rz rotations, with intra- and cross-group entanglement. The circuit measurement probabilities are fused with spectrogram transformer embeddings to estimate a grade on labels 2-5 and to surface technique-level feedback. On 168 labeled 20 second excerpts, the hybrid reaches 74.29% agreement with expert graders, a +12.86 point gain over a classical-features baseline. Processing is sub-minute per recording on a laptop-class Qiskit simulator; we do not claim hardware speedups. This is a feasibility step toward interpretable, objective singing assessment in applied audio signal processing.