Hi everyone,

Since the DLS format didn't really take off unlike soundfonts, there isn't really any DLS authoring software made in the recent years, and no real open source software either.
Yet there still are some cool DLS files out there: DLSByXG, Airfont, acapellaGMGS or CrysDLS just to name a few.

So I'd like to share the project I've recently released which might interest you:

https://spessasus.github.io/SpessaFont/

An online SF2/DLS editor, that's free and open source! It works with all the SF2 and DLS files I have.
It has the following features:

• Support for SF2, SF3 and SF2Pack (with Vorbis) files
• Support for DLS Level 1, DLS Level 2 and Mobile DLS
• Extracts DLS/SF2 from RMIDI files
• Converts from DLS to SF2 and back
• A MIDI player built-in
• Tools for stereo sample editing
• DMOD support
• xdta support
• A modern interface with both dark and light themes

Please report bugs if you find any.

I hope you like it.
Spessasus