Source:
https://www.smbxgame.com/forums/viewtopic.php?f=69&t=28300
Creator:
Yave Yu
Files:
Download=Cubic SMBX Sound.7z
Source WAV files=Cubic SMBX Sound - SourceWAV.7z
ReleaseDate:
2022-07-21

Description:
Did you feel SMBX2 and SMBX-38A's sound effects are little glumly? Because of Gaussian interpolation, hi-freq are gone! I know Gaussian is original SNES hardware's interpolation, but on modern device it sounds terrible due to lacks hi-freq, so I decided to record entire new sound effects from scratch, use Mesen-S the SNES emulator, it can edit SPC memory also has cubic interpolation audio, and it's newer emulator with high accuracy. Now here it is.
Note: I don't like “do” share “coin” sound, so “do” now is confirm sound (or correct sound in SMB1's maze level).