Vocal Effect? AM radio / CB radio

[jimosity]

I would like to build an effect that essentially sounds like a CB radio or AM radio effect for vocals.
Any schematics / layouts / PCB preferably for this sort of thing?
It'd be cool for guitar too, but I primarily want this for the occasional vocal effect that my singer can step on to engage when needed.

[rousejeremy]

Do a search for the LoFo MoFo. Might be what you're looking for.

[R.G.]

http://www.geofex.com/FX_images/lofi.gif