Vocoder FAQ

Answers to frequently asked questions about this software. Please e-mail me if your question is not answered here.

How about plug-ins for existing sound editors?

This is a good idea. I probably don't have the sound editor you want a plugin for (unless it's open-source), but am open to developing such a thing if I get access to the software and API. Also, the source code is available, so you could do it yourself. I'm happy to answer any questions.

How do I use this? Where are the icons, buttons, menus, etc.?

You are probably using an old version of the vocoder. Until September 2002, this program could only run from the command-line. Now, there is a graphical version for Microsoft Windows. Download it here: InstallZeriusVocoder13.exe

Why doesn't this third-party graphical front-end work?

I cannot answer the question because I did not write the front-end. Please contact the front-end's author instead.

The latest version of the vocoder includes its own graphical user interface for Windows, so rather than use a third-party graphical front-end, download the latest version using the link in the previous answer. I will, of course, be happy to answer any questions about that version.

Why not make a nicer windows interface?

Looks like I have to eat my words. The latest version has a graphical interface for Windows, so the answer is: I just did!

How does the vocoder work?

First, this is a channel vocoder, not a phase vocoder. Phase vocoders are used to pitch shift and time scale, and work differently.

For a channel vocoder, the basic algorithm works like this:

  • Split the modulator (formant) and carrier into frequency bands
  • For each frequency band:
    • Find the volume of the modulator band and modulate the carrier band with that volume
    • Mix the bands back together to form the output

That's all there is to it, really. Of course there are plenty of different ways to implement this. Most hardware and software vocoders use a series of band pass filters, envelope followers, and modulators to achieve the result.

My vocoder takes a different approach. It takes an FFT of the input signals, performs all its work in the frequency domain, and then does an inverse-FFT.

If you're still confused, this site has a good explanation.