Viewing Issue Advanced Details
|ID||Category [?]||Severity [?]||Reproducibility||Date Submitted||Last Update|
|07910||Sound||Minor||Always||Mar 20, 2021, 10:02||Apr 12, 2021, 04:52|
|Tester||sasuke||View Status||Public||Platform||MAME (Official Binary)|
|Assigned To||Resolution||Open||OS||Windows 10 (64-bit)|
|Version||0.229||Fixed in Version||Build||64-bit|
|Fixed in Git Commit||Github Pull Request #|
|Summary||07910: bcruzm12: Lack of explosion sound.|
All sounds when a player or enemy explodes do not sound.
PCB: (I'm Not sure why there is a difference in the loudness of the explosion between the both PCBs.)
|Steps To Reproduce|
|Flags||Verified with Original|
|Affected Sets / Systems||bcruzm12|
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
|There are no relationship linked to this issue.|
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.
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.
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.
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.|