DirectMusic Producer
From Video Game Music Preservation Foundation Wiki
DirectMusic Producer was once very popular: article on Microsoft's site here 'How to Use DirectMusic Producer to Create Music for a Video Game' and another guide here (Internet Archive) sample (Archive.today backup)
Formats to edit or play: SGT, STY, DLS, others?
However it only seems to run on Windows XP! (can use VirtualBox)
Download
- DirectMusic(r) Producer in DirectX(r) version 9 (DMP9.zip) download (Internet Archive).
- DirectMusic Producer DirectX 8.1 (DMusProd) (dx81musicproducer.exe) download (Internet Archive)