08219: a800xl: Bass voice missing in "Zybex" game music.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08219	Sound	Minor	Always	Feb 20, 2022, 05:31	Sep 2, 2022, 09:37

Tester	CYBERYOGI -CO-Windler	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Fixed	OS	Windows 10/11 (64-bit)
Status [?]	Resolved			Driver	atari/atari400.cpp
Version	0.237	Fixed in Version	0.247	Build	64-bit
		Fixed in Git Commit	ffc0db2	Github Pull Request #

Summary	08219: a800xl: Bass voice missing in "Zybex" game music.
Description	In "Zybex" on Atari 800XL there is a flickering line to the left of the screen, and the POKEY music is missing the bass voice! (It happens both in PAL and NTSC Atari, only in NTSC the music plays faster.) Please fix this. This is what the music should sound like on NTSC (written for PAL, it is originally slower): (I found the bug in 2021-10-21 in the at that time fresh MAME version, which was 0.237.)
Steps To Reproduce	Load the game Zybex and listen to the intro music.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	a800xl

Attached Files

No.19808 kmg Senior Tester Feb 20, 2022, 07:47 edited on: Feb 20, 2022, 07:49	https://github.com/mamedev/mame/issues/8911 is an existing report of the problem. The bass notes are being played in MAME, they are just at a pitch that's something like 2 1/2 octaves too high, i.e. moving at a parallel fifth to the correct bass line due to the unemulated POKEY mode.
No.19810 Tafoid Administrator Feb 20, 2022, 09:47 edited on: Feb 20, 2022, 09:47	"Please fix this." isn't needed in your bug descriptions. It does nothing to help diagnose, fix the problem, or inform the developers. As a reminder, always post the most recent version when posting bugs. It is assumed that all bugs reported have been tested and replicate in the latest release build before being posted. You posting 0.237 as offending MAME version doesn't help and only requires us to test current in which something may be already fixed. Please do not mix graphic and sound issues together in a bug report. The graphic issue is acknowledged with the machine being flagged with imperfect graphics (colored screen you need to acknowledge before starting the machine in MAME). No need to report bugs like that unless you have noted heavy regression (as per Rules). Please familiarize yourself with reporting rules and help (upper right side "Help" pulldown). Having to explain little things which should be known is becoming tiresome to both remind and to fix.
No.19831 CYBERYOGI -CO-Windler Viewer Feb 22, 2022, 06:30 edited on: Feb 22, 2022, 07:14	Is POKEY emulation still imperfect? I always thought its shifregister feedback noise source was used as protection inside early Atari arcade games and so had to be implemented perfectly to make such games work. (The graphics glitch was minor and not what I complained about. It may even exist on real hardware and get hidden by overscan of an actual CRT monitor. And I would not have complained about an "old" MAME version when I assumed it to be fixed in the current version. (I did not see POKEY things mentioned in recent whatsnew.txt.) My MAME is on a different computer, so I can't quickly check from here if the bug is still valid.)
No.20491 M.A.S.H. Senior Tester Aug 28, 2022, 09:54	Improved accuracy of POKEY emulation: https://git.redump.net/mame/commit/?id=ffc0db2fdc8aac2258877e23fadee5265ad7a1c3 "Zybex" game music sounds better now. Is it fixed?