Kits AI vs SoulX-Singer

Kits AI provides audio tools for creating and changing voices and working with vocals and music. Its features include voice cloning and conversion, vocal enhancement and removal, stem splitting, AI mastering, harmonies, pitch editing, and key and BPM detection. The voice-changing tools include a library of 100+ royalty-free artists. A Windows desktop app supports drag-and-drop into a DAW or other music production software and simultaneous auditioning of multiple vocal models; Kits AI is also available through a browser and API. The API lists voice conversion, blending, and vocal removal endpoints, while text-to-speech was deprecated from the API as of September 22, 2025. Kits says voices used in its models are licensed and sourced from artists, who benefit through revenue sharing. The free plan includes 15 conversion minutes, no voice slots, and no download minutes. Paid plans start at $10 a month. Submitted and generated audio may be used to improve the services, including related AI and machine learning models.

SoulX-Singer is a singing voice synthesis model that generates voices for singers it has not been tuned on. Pitch, rhythm, and expression can be guided by melody-conditioned F0 contours or score-conditioned MIDI notes. Its voice-conversion system changes raw singing audio to a target singer’s voice while retaining melody, rhythm, and lyrics, without requiring lyric or MIDI transcriptions. It supports Mandarin Chinese, English, and Cantonese, plus singer-timbre cloning, cross-lingual synthesis, and lyric editing while retaining natural prosody. Preprocessing tools handle vocal separation, dereverberation, F0 extraction, voice activity detection, and lyric and note transcription. Users can edit MIDI metadata, including lyrics, phoneme alignment, pitches, and durations, before synthesis. Soul-AILab provides generation and conversion demos and a separate MIDI editor through Hugging Face Spaces; the repository also supports local inference. Code and model weights use the Apache 2.0 license. Maintainers caution that automatic preprocessing may misalign singing with lyrics and notes, so manual correction may be needed.