How to convert .mp3 audio to .dlp format.
Converting MP3 Audio Files directly to DirectMusic Producer DLS (.mp3 to .dlp conversion) should be possible, even though your options are limited.
Try using an audio editing software or (online) conversion tool, such as DirectMusic Producer or Awave Studio, which should allow users to import MP3 audio files and export them in DLP format.
Audio editting software with huge format support
A music authoring tool distributed with Microsoft DirectX SDK