Sonosync is a free iPhone app that offers a collection of relaxing music designed to sync with your resting heartbeat. The app includes a full album of soothing compositions that can help improve relaxation and promote better sleep.

With the free version, users can listen to five full-length compositions at the highest tempo. The music has been professionally mastered for optimal listening on iPhone and iPad, and it is recommended to use headphones for the best audio experience. However, the mixes have also been optimized for the device's built-in speakers.

For those looking for more control and additional features, the app offers an unlock option. By unlocking the app, users gain access to all three variations of each composition, allowing them to choose the tempo that is most relaxing for them. Over time, users may find themselves gradually moving to slower versions as their relaxation levels increase.

One of the standout features of Sonosync is the sleep timer. Users can set a timer to automatically fade out the music, helping them drift into a peaceful sleep. Additionally, the app includes 36 beautiful photos that automatically play in the background, enhancing the overall relaxation experience.

Overall, Sonosync is a great app for anyone seeking to relax, unwind, and improve their sleep quality. With its collection of soothing music and additional features, it provides a comprehensive relaxation experience for users.