03297: smashtv: Music sputters/lags when doors open

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
03297	Sound	Minor	Always	Jul 5, 2009, 20:30	Dec 18, 2020, 07:54

Tester	Yonah	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Bugs That Aren't Bugs	OS
Status [?]	Resolved			Driver	midway/midyunit.cpp
Version	0.132	Fixed in Version		Build
		Fixed in Git Commit		Github Pull Request #

Summary	03297: smashtv: Music sputters/lags when doors open
Description	From the start of game play in the first room, the background music seems to lag or sputter while playing the game. This seems to happen when a door opens either to bring in more enemies or while the player is moving to the next room. When the sound CPU is over-clocked to 150% these sound problems are alleviated. Most interestingly, if the CPU is under-clocked by even as little as 95% these problems become severe very quickly.
Steps To Reproduce	1) Start the emulation 2) Go to "Slider Controls" 3) Lower the volume of the DAC and CVSD volume to 0.00 4) Play the game, listen for tempo interruptions, particularly with bass notes. 5) Reset the game (shift + F3) 6) Adjust CVSDCPU to 150% 7) Play the game, notice the lack of sound problems. 8) Reset the game (shift + F3) 8) Adjust CVSDCPU to 90% or below. 9) Notice how sound problems become worse.
Additional Information	I have included 2 files, both with DAC and CVSD muted, one at normal CPU speed, the other Adjusted to 150% above normal. Over the weekend I located a SmashTV machine of unknown version at a local establishment. If necessary I could try to get a sound recording of the game if no one else has access to the real hardware, though I lack the proper equipment to do this and the noise levels in the surrounding are excessive.
Github Commit

Flags
Regression Version
Affected Sets / Systems	smashtv

Attached Files	Normal.mp3 (1,406,825 bytes) Jul 5, 2009, 20:30
Attached Files	Adjusted.mp3 (1,407,589 bytes) Jul 5, 2009, 20:31

No.04620 Tafoid Administrator Jul 6, 2009, 11:02	If there is indeed a problem, I'm fairly sure that the cpu speeds are not the fault. Midway Y Unit is well documented. Pending some actual PCB investigation and recordings, I would mark as possible. Since it's not possible to mute channels in the arcade game - this might have never been noticed as original behavior. I'll wait for the authority to chime in on this, however.
No.18277 MetalGod Senior Tester Dec 18, 2020, 07:36 edited on: Dec 18, 2020, 07:45	The sound bug is present in the original hardware too. It is perfectly noticeable while crossing the door in level transitions as I'm showing in the video below. Due to the gameplay sounds effects, it is harder to check when doors open for enemies to come into the arena, but it is also noticeable anyway: