Assuming it was uninstalled, I have no idea.
You get an uninstaller program such as Revo Uninstaller. Install Revo, reboot, then reinstall MorphVOX, then use Revo to uninstall it and scan for leftovers. That will ensure it is all removed. Then reboot again.
Aside from that, if audio is still being affected, then it's most likely another application.
I will also add that some sound card drivers/software have similar features. Ensure you haven't altered something there.