[Feature] differences in AY-3-8910 and YM2149 sound [sf#90]

[openMSX-import]

Reported by guyver800 on 2004-09-25 20:13 UTC
There exist subtle differences between AY-3-8910 chips
used in some MSX's and Yamaha YM2419 chips used in
others (and presumably incorporated in the various
MSX-Engine chips).
The sound of an AY-3-8910 is warmer (due to different
frequencies in the output) and it has different
envelope timing.

openMSX should emulate these differences and use the
correct emulation for the various MSX models.

[openMSX-import]

Commented by mthuurne on 2004-09-25 20:28 UTC
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Do you have any details about the differences?

The current implementation is based on code from MAME and the
AY-3-8910 data sheet.

[openMSX-import]

Commented by manuelbi on 2006-05-11 10:07 UTC
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This thread contains some pointers:
http://www.msx.org/forumtopicl6210.html

Quoting:

It was discussed to death in russian ZX Spectrum forums.
Basically GI AY chips and Yamaha YM chips are slightly
different, where AI uses 4 bits for duration and YM uses 5.
This make sounds a bit shorter and so same melody sounds a
bit harsher on YM. Mr Bulba Wrote software AY/YM emulator
that accounts for all those differences.

AY can be found in most MSX1 systems. YM and integrated YM
is in all MSX2 and higher. Notable exceptions are Arabic
MSX1 systems and Brazilian Expert+ with Toshiba MSX Engine
chip. I think it sounds more like YM hten AY.

[openMSX-import]

Commented by manuelbi on 2006-05-23 06:53 UTC
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This has been implemented now. TODO: put YM2149 in the
proper config files; indeed all machines with MSX-ENGINE (at
least the S3527 one) have a built in YM2149. I'll close this
after this has been (mostly) done.

If there's any problems with it, please file a bug report.
You can also file a bug report if a config file has the
wrong type of PSG.

[openMSX-import]

Updated by manuelbi on 2006-05-23 06:53 UTC

• priority: 5 --> 3
• assigned_to: nobody --> m9710797
• summary: differences in AY-3-8910 and YM2419 sound --> differences in AY-3-8910 and YM2149 sound

[openMSX-import]

Commented by manuelbi on 2006-05-26 14:03 UTC
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The types have been added to all machines of which we are
sure about the type. If something is still missing, please
file a bug report.

[openMSX-import]

Updated by manuelbi on 2006-05-26 14:03 UTC

• status: open --> closed