# For singing voice conversion, how do Seed-VC and so-vits-svc handle pitch, and what did Seed-VC measure against RVCv2?

- id: art_01M5NCFFG198DVGFS4F5G2GQZR
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T13, T14 · tags: none
- updated: 2026-10-23T22:00:37.627Z
- url: https://veyrul.com/articles/art_01M5NCFFG198DVGFS4F5G2GQZR

Problem. Speech VC settings damage singing: automatic pitch prediction drifts and pitch range mismatches produce wrong notes. Conditions. Converting vocal stems (isolated, dry) to another timbre. Method. Seed-VC conditions the model on source F0 (extracted with RMVPE, quantised into 256 bins) and shifts F0 by gender or semitone setting between source and target; its README says to enable f0-condition and use 30 to 50 diffusion steps for singing. so-vits-svc warns not to use auto_predict_f0 for singing because it can cause serious pitch issues, and says silence-slicing minimum interval can be lowered to about 100 or 50 for singing. Measured result (author-reported, Seed-VC paper Table 2): on singing, Seed-VC SECS 0.7405 vs RVCv2 0.7264, both F0 correlation about 0.94, Seed-VC lower CER, RVCv2 slightly better DNSMOS. Failure modes. Wrong octave or key shift; auto pitch on; accompaniment bleed in the input (RVC README points to Ultimate Vocal Remover for stem separation; inference that...

Problem. Speech VC settings damage singing: automatic pitch prediction drifts and pitch range mismatches produce wrong notes. Conditions. Converting vocal stems (isolated, dry) to another timbre. Method. Seed-VC conditions the model on source F0 (extracted with RMVPE, quantised into 256 bins) and shifts F0 by gender or semitone setting between source and target; its README says to enable f0-condition and use 30 to 50 diffusion steps for singing. so-vits-svc warns not to use auto_predict_f0 for singing because it can cause serious pitch issues, and says silence-slicing minimum interval can be lowered to about 100 or 50 for singing. Measured result (author-reported, Seed-VC paper Table 2): on singing, Seed-VC SECS 0.7405 vs RVCv2 0.7264, both F0 correlation about 0.94, Seed-VC lower CER, RVCv2 slightly better DNSMOS. Failure modes. Wrong octave or key shift; auto pitch on; accompaniment bleed in the input (RVC README points to Ultimate Vocal Remover for stem separation; inference that separation quality bounds result quality). Limits. Small eval, per-character RVC baselines trained by the paper's author. Version/date. Seed-VC v1 paper Nov 2024; so-vits-svc 4.1-Stable.

Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources.

Limitations: Table 2 values are the paper author’s, with RVC models he trained; the RVC credit line is a link list not a recommendation.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://arxiv.org/pdf/2411.09943",
      "note": "Sec 3 / singing; Sec 4.3; Inference args; Credits"
    },
    {
      "url": "https://raw.githubusercontent.com/svc-develop-team/so-vits-svc/4.1-Stable/README.md",
      "note": "Sec 3 / singing; Sec 4.3; Inference args; Credits"
    },
    {
      "url": "https://raw.githubusercontent.com/RVC-Project/Retrieval-based-Voice-Conversion-WebUI/main/README.md",
      "note": "Sec 3 / singing; Sec 4.3; Inference args; Credits"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] Problem. Speech VC settings damage singing: automatic pitch prediction drifts and pitch range mismatches produce wrong notes. Conditions. Converting vocal stems (isolated, dry) to another timbre. Method. Seed-VC conditions the model on source F0 (extracted with RMVPE, quantised into 256 bins) and shifts F0 by gender or semitone setting between source and target; its README says to enable f0-condition and use 30 to 50 diffusion steps for singing. so-vits-svc warns not to use auto_predict_f0 for singing because it can cause serious pitch issues, and says silence-slicing minimum interval can be lowered to about 100 or 50 for singing. Measured result (author-reported, Seed-VC paper Table 2): on singing, Seed-VC SECS 0.7405 vs RVCv2 0.7264, both F0 correlation about 0.94, Seed-VC lower CER, RVCv2 slightly better DNSMOS. Failure modes. Wrong octave or key shift; auto pitch on; accompaniment bleed in the input (RVC README points to Ultimate Vocal Remover for stem separation; inference that separation quality bounds result quality). Limits. Small eval, per-character RVC baselines trained by the paper's author. Version/date. Seed-VC v1 paper Nov 2024; so-vits-svc 4.1-Stable. · locator: Sec 3 / singing; Sec 4.3; Inference args; Credits · source: https://arxiv.org/pdf/2411.09943

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