Despite being a free plugin, this is perhaps the best vocoder I tried to date. As the name suggests, it is intended not for those ugly robot-voices or sci-fi effects but to actually *sing* ! With an accurate choice of the proper carrier (for example by using an external analog synth as I do, even if the builtin synth does a nice job already) you can literally produce choirs or even solo vocals with a fidelity I would have never expected by a vocoder. This goal is perhaps achieved by the choice of using as many as 512 bands. The author made definitely a great job. Only drawbacks, if we want: no 64-bits version available; with Reaper I often experience crashes when loading a project with multiple instances of Cantante (but I can't tell whether it is a bug with Reaper or with Cantante itself). If you are looking for something more than just robot-voices, well, try this vocoder and consider a donation!
This tool is impressive indeed, clear and very pleasant to the ears! :) I only have a problem with it, I don't know if it's my computer or the effect: it only works as a master effect, which seriously limits its use and makes working with it very complicated. Is it my set-up or is that a choice by the developer? It would be fantastic if it could be made to work as an insert effect, too...
The plugin really just provides the inputs and outputs, the rest is a matter of the routing capabilities of your DAW. I use Reaper, and it is really easy to set up, but it should not be a problem for most other DAWs. The routing is similar to compressor sidechaining.