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ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
08578 Sound Minor Always Mar 6, 2023, 02:34 Mar 9, 2023, 19:55
Tester danylopez123 View Status Public Platform MAME (Official Binary)
Assigned To hap Resolution Fixed OS Windows 10/11 (64-bit)
Status [?] Resolved Driver
Version 0.252 Fixed in Version 0.253 Build 64-bit
Fixed in Git Commit 506e00a Github Pull Request #
Summary 08578: snowbro2: The OKI MSM6295 sound chip haves lower MHz
Description While listening to the VGM pack, i asked myself: How come in this pack, the OKI sound chip sounds slightly faster than the how i heard it in MAME?
I checked the info file and it says: I changed 2700000Hz to 3300000Hz from the clock OKIM6295 based on the Sound of the real hardware.

If i want to verify this, i tried to search if there's any video of Snow Bros 2 being played from an actual PCB, to my surprise, i've managed to find one, it's from a Spanish youtuber.

I could tell at the beginning of the attract/intro sequence listening to the Girl's Scream, in that video, it sounds with a Higher pitch.
I know the dude in the video talks alot but you can kinda hear the voices from the game.
Here's the video:

And here's the VGM pack where i saw the info file:
Steps To Reproduce
Additional Information
Github Commit
Flags Verified with Original
Regression Version
Affected Sets / Systems snowbro2
Attached Files
jpg file icon sb2_xtals1.jpg (315,851 bytes) Mar 6, 2023, 18:42 Uploaded by Haze
jpg file icon sb2_xtals2.jpg (332,857 bytes) Mar 6, 2023, 18:43 Uploaded by Haze
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User avatar
Senior Tester
Mar 6, 2023, 18:43
edited on: Mar 6, 2023, 18:58
There is no 33Mhz XTAL on the original PCB, the one closest to the sound section is 16.

It is likely the clock should be derived from that 16Mhz XTAL though, as 27mhz is for the video, while the 32 is for the CPU.
User avatar
Mar 7, 2023, 14:02
OKIM6295(config, m_oki[0], 27_MHz_XTAL/10, okim6295_device::PIN7_HIGH);

so simply change to this?:
OKIM6295(config, m_oki[0], 27_MHz_XTAL/8, okim6295_device::PIN7_HIGH);
which makes it the same as the YM clock in the driver.
User avatar
Senior Tester
Mar 7, 2023, 23:43
It still seems unlikely that the sound clocks would derive from the 27 on these to me.

32/2 makes sense for the CPU
27 is confirmed as the video on multiple Toaplan boards
the 16 in the sound section is surely where the sound clocks come from?
User avatar
Mar 8, 2023, 11:14
YM clock is correct, when comparing to the video, it can't be from the 16MHz XTAL.

My ears say the OKI clock is this:
OKIM6295(config, m_oki[0], 16_MHz_XTAL/4, okim6295_device::PIN7_LOW);

Yes I agree the cpu should be 32/2