The following are some useful voice changers for music production:

1. **Voicemod**: This is a free voice changer software that allows you to use Windows and Mac used on the system. It offers a variety of sound effects, including male, female, child, animal, and robot, among others. You can use the built-in sound effects library to add sound effects and background music. It also supports speech recognition and synthesis to reduce audio noise and enhance sound.

2. **Audacity**: This is a free open source audio editor that can be used to record, edit and mix audio files. It offers a variety of sound effects, including equalizer, compressor, noise reducer, and more. You can use these tools to change your voice to make it more natural.