Have we already discovered all of the sound effects in NSMB? We (or at least I) thought it was only the sound sets at first, but I saw a YouTube video from Skawo and it turned out some sound effects will only play when a certain background is set.

Actually the problem you're describing is the same as the one showcased in this thread.

Luckily this also means the fix is the same in this case:

This way there is no restriction anymore and theoretically any SFX can play regardless of the settings.
This will allow you to test for undiscovered SFX, if any.

No, that is not that problem. The "15: Volcanoes 2" subbackground loads sound effects for the falling meteors. It's possible others do as well.



Well, the sound set settings still matter, don't they?

Of course they do, but in my head it sounded (ironically enough) so obvious.


This get even weirder because the Falling Debris (Actor 121) will play a sound when crashing into something, regardless of the background, as long as the Sound Set is set on 0B.
But the exploding sound they play when they get launched into the stratosphere will only play when they specifically are loaded from BG 15 or 16 and Sound Set is set on 0B (Actor 121 by itself won't play this one sound even if the current backgrounds are the right ones).


I think BG 15 and 16 have that property because they "interact" with the player so to speak.
BG 5 and 57 might be worth to look at due to the fact that those BGs automatically assume that Mario is underwater (hence the interactive part) as long as the Y-coordinate is above 0, but that property might be completely unrelated to the Sound Set.

Can't think of any other background worthy a shot right now, other than the BGs who load the Boss SFX but those were already covered.

I found that they didn't play the crashing sound if I didn't have the background set to 15, actually, so dunno.

I don't know; it's retarded.