Spectrogram Plus is an application I'm developing that will hopefully be useful to those in voice therapy or those interested in modifying their voice in some way. Voices are not made of one frequency, like the base pitch most people know about, they are made of a combination of signals at different frequencies. The strongest components of those are known as the resonant frequencies of voice, and by modifying those you can change how the voice sounds. Many voice processing tools only shift the base pitch or they shift the entire frequency scale. The point of this project is to include tools to modify specific resonant frequencies and observe how that changes the quality of the voice.