Sur Sadhana is a free app developed by Clood On Musica and offered by the Shankar Mahadevan Academy. It is designed to help users learn and master the basics of singing Indian vocals. The app provides a comprehensive guide to basic notes and patterns, with a visual representation of the user's performance and a score to help track progress.

One of the best features of Sur Sadhana is its customization options, allowing users to adjust pitch and tempo to suit their individual needs. The app is easy to use and comes with a user-friendly interface, making it accessible to anyone who wants to learn to sing Indian vocals.

Overall, Sur Sadhana is an excellent app for anyone who wants to learn the basics of Indian vocals or improve their singing skills. With its comprehensive guide, customization options, and user-friendly interface, it is a must-have for budding singers. And the best part is that it is completely free!