Keep in mind that, despite the similarity in the names, "SoundFont" (.sf) and "sfz" (.sfz) are two different animals.

SoundFont was designed by Creative Labs as a portable sample format that worked well with their sound card technologies. It was pretty big back in the day when Creative Labs was big. Now, it's pretty much obsolete, but there are plenty of SoundFont libraries around.

SFZ was created by Plogue, and is a (mostly) open format that can be edited in plain text. It's still being used by a number of companies, such as Garritan.

The sforzando player can convert SoundFont files into .sfz files, but how well it works depends on what sort of features it uses. If it's mostly sample playback, the conversion will often be quite good.

-- David Cuny
My virtual singer development blog

Vocal control, you say. Never heard of it. Is that some kind of ProTools thing?