Voice SSL v5: External False Positive Rate Reduced to 0.02%
The v5 multi-source training approach resolved the critical external false positive problem identified in v2. By training on diverse benchmark voice corpora beyond the original baseline, the model now correctly identifies real human speech from previously unseen recording environments.
Problem
Voice SSL v2 achieved strong detection metrics (EER 1.0%, 99.54% detection rate) but exhibited a high false positive rate on external bonafide datasets — real human recordings from unseen environments were frequently misclassified as AI-generated. Root cause: the model had only seen a narrow recording environment during training.
Solution
v5 training incorporated bonafide samples from multiple benchmark voice corpora, totaling tens of thousands of samples with domain-weighted sampling to maintain source balance.
Results
| Metric | v2 | v5 (pc4) |
|---|---|---|
| EER | 1.00% | 1.00% |
| Overall Detection | 99.54% | 98.96% |
| External Bonafide FP | ~49% | 0.02% (2/8,775) |
Training reproducibility was verified across 4 independent PCs with different hardware configurations. The pc4 model (Ultra 9 285K + RTX 5060) was selected as the v5 reference model.
v5 trade-off: one legacy benchmark synthesis method dropped from 97.5% to 90.5% detection. This particular attack type has limited real-world relevance.

