Comprehensive iPhone Voice-Changing App Discovery

As a growing professional in need of novel communication methods, I require a talented individual who can help me discover a robust voice-changing application for iPhone. This app should grant the user ample control, offering both preset voice effects and the ability to tailor voice effects to specific needs. Furthermore, I would appreciate it if this application could be multi-functional, affording me the ability to manipulate voices during calls, as well as in pre-recorded audios.

While the core function of the application lies in voice transformation, the presence of auxiliary features like background noise simulation or sound effects could be valuable. However, I am currently unsure whether I require these, leaving it up to the discretion of the expert to present such suggestions.

Ideal Skills and Experience:
- Extensive knowledge about mobile apps
- Working knowledge of voice changing software or apps
- Familiarity with iPhone compatible tools
- Strong communication and suggestion skills