Move the sliders to select your low and high notes or use the Quick Range box. Here is a guide to vocal ranges from Wikipedia

• Soprano : Low - C4 , High - C6
• Mezzo-soprano : Low - A3, High - A5
• Alto : Low - G3 , High - F5
• Contralto : Low - F3 , High - F5
• Tenor : Low - C3, High - C5
• Baritone : Low - F2, High - F4
• Bass : Low - E2, High - E4