AQUEST has released AquesTone 2, an improved version of their freeware vocal synthesizer VSTi plugin for Windows.
AquesTone2 AquesTone2 is a software-based synthesizer vocal. It supports VSTi plug-in, you will be able to easily generate the singing voice information from the text and lyrics MIDI.
The website is in Japanese, so I’ve provided a Google Translate version of the download page in the download section below. Here’s the link to the original AquesTone 2 download page.
Basically, what you’re getting here is probably finest freeware vocal synthesizer out there. It is your free ticket to Vocaloid style vocals, provided that you’re using a Windows based DAW. Although I’ve never used AquesTone in a finished tune, I use it for sketching vocal tracks all the time and it’s a fantastic tool for that purpose.
Please note that there’s a note on the product page, which says that the link will expire in May 2013. I’m not sure if the plugin will go commercial, or that they will simply release an improved freeware version in May.
UPDATE: Our reader arkmabat contacted the developers and they told him that the new version of the plugin will be released once the old one expires.
ENGLISH MANUAL: Our reader kechi2dtm has provided an unofficial English version of the manual on his website: AquesTone 2 Manual (English)
Video Demo
Check out the AquestTone demo video (old version):

Download
AquesTone 2 is available for free download via AQUEST (216kB download size, 32-bit VST plugin format for Windows).