07910: bcruzm12: Lack of explosion sound.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07910	Sound	Minor	Always	Mar 20, 2021, 10:02	Nov 21, 2022, 10:16

Tester	sasuke	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10 (64-bit)
Status [?]	Confirmed			Driver	orca/marineb.cpp
Version	0.229	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07910: bcruzm12: Lack of explosion sound.
Description	All sounds when a player or enemy explodes do not sound. MAME: PCB: (I'm Not sure why there is a difference in the loudness of the explosion between the both PCBs.) #t=13m17s
Steps To Reproduce
Additional Information
Github Commit

Flags	Verified with Original
Regression Version
Affected Sets / Systems	bcruzm12

Attached Files	ETC-0116_BHN1.jpg (684,364 bytes) Mar 20, 2021, 15:59 Uploaded by jkburks Battle Cruiser M-12 PCB Front
	ETC-0116_BHN2.jpg (695,296 bytes) Mar 20, 2021, 15:59 Uploaded by jkburks Battle Cruiser M-12 PCB back
	D66CgHJUYAAcNbw.jpg (2,029,303 bytes) Mar 20, 2021, 16:31 Uploaded by jkburks Battle Cruiser M-12 PCB Front Angle
	battle_cruiser_m12.jpg (1,139,103 bytes) Nov 21, 2022, 10:16 Uploaded by M.A.S.H. Battle Cruiser from Mike McBike

No.18587 Tafoid Administrator Mar 20, 2021, 12:44 edited on: Mar 20, 2021, 12:45	I'd bet it is discrete sound. No manual seems to have been scanned to examine - so we'd need some very good pictures of the PCB to determine what's up.
No.18588 jkburks Tester Mar 20, 2021, 16:02 edited on: Mar 20, 2021, 16:35	These two PCB photos are the best I could find. I'm not sure if the front photo is high enough resolution to get positive ID on the resistor stripe patterns. The game manual shows up on auction sites from time to time, but I have only seen low resolution photos of the cover, never the pages or schematics. Edit - found another photo of the PCB front and uploaded it. For some reason it is not showing a preview, so just click the link below the second PCB photo.
No.18673 dink Tester Apr 12, 2021, 01:06	Can anyone find a better front pcb pic, with readable chip numbers to the right of the GI AY-3-8912's? There's another sound missing from emulation, it's the low pitched "atmospheric" noise that plays constantly when the machine is switched on. Possibly some sort of leakthru from the explosion circuit? After some digging: I believe the first ay's output port control the background warble / atmospheric noise and the first output port on the second ay triggers the explosion. 2 for enemies, 6 for the player's ship (louder) regarding the explosion volume differences in the reference videos above. It's simple - the first one is played using a little speaker or tv's speaker (out of cabinet) and the other 2 videos are played on an arcade cabinet, which houses a nicely-sized speaker.
No.18679 AJR Developer Apr 12, 2021, 04:52	To my eyes, the four ICs to the right of the first AY-3-8912 are SNALS74N (4D), SN74LS161AN (3D), MC14006B (2D) and MC14070B (1D). The last two of those, with a bunch of discrete components surrounding them, suggest some variant of the CMOS LFSR+astable white noise generator Space Invaders uses for explosions.
No.20848 M.A.S.H. Senior Tester Nov 21, 2022, 09:54 edited on: Nov 21, 2022, 10:19	There are unmapped writes to AY-3-8912 Port A everytime an explosion happend! 'mame bcruzm12 -log' listed this: [:ay2] warning: unmapped write 02 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 00 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 02 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 00 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 02 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 00 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 06 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 00 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 02 to AY-3-8912A PSG Port A [:ay2] warning: unmapped write 00 to AY-3-8912A PSG Port A Also added a better PCB picture from Mike McBike!