Applio vs SoulX-Singer

Applio is an open-source AI voice conversion suite for making covers, training custom voice models, and changing voices in real time. It can convert recorded audio with ready-made models, plus pitch tuning, cleanup, upscaling, and batch processing. Live conversion is intended for songs, streams, and calls. Model tools include training, a voice blender, text-to-speech, and an audio analyzer for dataset readiness. Applio supports Linux, macOS, Windows, web, and self-hosted use; Google Colab, Pinokio, and Hugging Face are also listed as ways to run it. Its plan is free, with no accounts or paywalls. The MIT license permits personal, research, and commercial use. The maker says audio and models remain on the device unless shared, and core features do not require an account, telemetry, or cloud dependency. Documentation recommends an Nvidia RTX 20-series GPU or newer for local voice training; most modern computers can handle inference with existing 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.