Vocoder

Vocoder is a simple application designed to help you modulate two sound files, thus creating a wide range of sound effects. Although sound modulation is one of the features packed in most professional sound tools, the extremely user friendly interface of Vocoder convinced us not to overlook it.
It is quite straightforward and intuitive, this making it easy to use even by the most inexperienced of us. In fact, even if you are not familiar with the terms it uses in the interface, in no more than a couple of minutes you can learn basics by simply trying different combinations.
What it actually does is use two sound files, the modulator and the carrier and a series of minor adjustments to provide you with a unique sound that results after the modulation takes place. The application was especially designed to make it sound like an instrument is talking (the famous robot voice used by Disco music back in the nineties).
To get this effect, you should use as a modulator the speech file and as carrier the instrument sound. Moreover, Vocoder allows users to create a large number of modulation effects making use of the Band, Window and Overlap slide bars.
The Bands slider allows you to adjust the number of bands that remain after the modulation process, the Window slider enables you to control the amount of audio it examines at one time, and finally, the Overlap slider is where you can specify how much of the previous Window is mixed with the current one.
If you want to test multiple adjustments, all you have to do is use the Preview button and get a glimpse of the result. When you are content with your settings, just press the Render button and the application saves the modulation file to the user defined location.
On the downside, Vocoder is actually mediocre when it comes to modulating. It only renders mono 16 bits WAV files. Moreover, it only works with mono sound files as modulator or carrier. So it can be an interesting tool for newcomers but it is not designed to satisfy the needs of a professional sound editor.