These require (paid).
UTAU is the most popular free alternative. Voicebanks come in (easy) or multiple pitch (expressive). Top picks: free vocaloid voicebanks top
The official VOCALOID engine by Yamaha is a paid commercial product, but beginners can utilize the following "free" gateways: VOCALOID6 Free Trial: Yamaha offers a 31-day free trial of the full VOCALOID6 Editor , which includes a standard library of 18 AI voicebanks (as of version 6.6) for testing. Mobile VOCALOID Editor on iOS includes a 14-day free trial that features , allowing for basic mobile production. VX-β Prototype: research-stage plugin bundled with VOCALOID6 that explores new synthesis methods. 2. Top "Freeware" Alternatives (The UTAU Ecosystem) These require (paid)
: This is the most famous completely free alternative. It is an open-source tool where the community has created thousands of free voicebanks. OpenUTAU is the modern successor, offering a more user-friendly interface and support for newer voicebank formats. Top picks: The official VOCALOID engine by Yamaha