Hello everyone! I'm finally here with a meaningful contribution to this community!
After much experimentation, I have come up with a foolproof way to convert other soundfonts for use with your Diamond board! (In theory, this should also work with Obsidian V4 (or earlier if you use the LSU converter) but I cannot test this, feel free to chime in if it does).
The tutorial that has existed on here for a while is sadly broken thanks to Photobucket, and honestly, IMHO it is long outdated and this method is way simpler and WAY faster. Gone are the days of converting each file one-by-one. Now you can convert a whole font to work in the USLauncher in under a minute!
Without further bravado, here is the tutorial:
https://www.youtube.com/watch?v=6mjK-KR4kG0The free conversion software:
https://www.mediahuman.com/audio-converter/Out of respect for the rules of this forum I will not directly post a link here to the font I used in the example, but there is a link in the video description if you want it.
I DO NOT CONDONE SOUNDFONT PIRACY. Please do this legally.
Note: this method works mainly for Plecter-optimized fonts; it will still technically work for NEC, but those fonts are unmixed and so you're going to need to do extra work to mix the idle hum back into every effect before you convert it over. If you plan on buying fonts to use with this method, go Plecter if at all possible.
Also note: due to the normalization feature of the USLauncher/Diamond, there is a good chance your volume will be all over the place after this; you will need to tweak your volume in the Effects editor to make your idle match your other effects, at least until the hopeful day that RSX makes the normalization a toggleable option (pleeease <3 ).
Please let me know if you have any questions, and I hope this brings a lot more fun and versatility to the Ultrasabers community!