How Do Sounds Work?

[mzxrules]

An incredibly bizarre glitch was discovered semi-recently:

 

 

And it made me realize that I don't know how sound effects work. Anyone know?

[SanguinettiMods]

It's probably some glitch in the play sound function. When a sound effect is called it looks like this:

 

BXXX where B = "SE HD" and XXX = "SE No." according to my probably faulty documentation.

 

The first X of "XXX" is also usually 8, and one is added on when an "SE No." reaches 100 or more.

 

I don't have any real information on how to answer this.

BXXX

B = "SE HD"
X? = 8 "SE No."
XX = "SE No."



0 = Player
1 = Item
2 = Environment
3 = Enemy
4 = System
5 = Ocarina
6 = Voice

[Jason777]

This documents how playing SFX work in audio debug: http://www.cs.utexas.edu/~jason777/Izou_Zelda/Misc/Hacking%20Notes/Audio_Debug_PlaySound_800F2C34_800F2CA8.txt

 

According to my notes, SFX numbers are decided like this:

((SE HD << 12) + SE No. + 0x0800) & 0xFFFF

Relevant RAM Addresses found on: http://www.cs.utexas.edu/~jason777/Izou_Zelda/Misc/Misc_NOTES.txt

80210B2C 0001 - Audio Debug Enabler

80131F20 (Audio Debug - SE Parameter Change)
0x0 (2 bytes) - SE HD
0x2 (2 bytes) - SE No.

external_func_800F738C(u16 sfx_id, void * a1, u16 a2) // "PlaySound" used by Audio Debug
external_func_8002F828(u16 sfx_id, void * actor) // PlaySound used by regular actors (wrapper for 800F738C)
external_func_8002F7DC(u16 sfx_id, void * actor) // PlaySound used by Link (wrapper for 800F738C)

8016BAB8 - Controller 4 Buttons (Audio Debug Input)