This is a music player built using the Javascript Web Audio API.
My a cappella group, Orange Appeal, practices music using files we have uploaded in a Facebook group. Each part has their own file for each song with their part louder than the rest, and there's also a master file with balanced audio. This means that for every song we sing, there are 6 tracks floating around in our group, which is laborious to create and manage and becomes quickly disorganized, with hundreds of files and a lot of scrolling to get to the right file. Additionally, this requires that members download mp3s onto every device they use to practice, which creates an additional layer of labor needed to practice music.
This audio player loads in 5 audio files (solo, tenor 1, tenor 2, baritone, and bass), and plays them all synchronously. It also allows for live manipulation of volume levels, so any part can go to one page and switch quickly and easily between different balance levels.
The way the application is built allows for lots of customization on a song-by-song basis. Adding or removing a part takes only a couple of minutes, and creating new songs is just a matter of copying the page and changing file locations.