Homebrew ROMEO2 - what is it exactly?

[~Stenny]

You can feel improved sound quality only when you use DSi(LL) or ROMEO2 slot2 sound board. Sound quality on DS(lite) improved little even though processing became slow.

Sound hardware; [bad sound] DS(lite) < DSi(LL) < DS(lite)+ROMEO2 [good sound]

i was downloading Moonshell Zwai now to get the voice recorder, so i read the changelog and now i'm curious: what is a ROMEO2 sound board? i did a quick search and found this link, but i don't know japanese.

is it a homemade sound board with a GBA game printed circuit board, plus some strange kind of cable and a application coded specifically for the tests?

thanks in advance. :3

 

[Sausage Head]

This was asked on Ask GBAtemp, in the NDS section.
"What's ROME02?"