MiSTer FPGA Forum

Hi there.

There's definitively an issue with audio on the core. It has something missing on the implementation that emulators have.
https://github.com/MiSTer-devel/MacPlus_MiSTer/issues/7
e.g. check Lode Runner with MiniVMAC emulator and check it with our beloved core, and it's absolutely missing the Lasers and falling FX.

This core is based on Plus_Too, so I opened a ticket and gyurco asked me for documentation on how it should be implemented, but I found no information.
https://github.com/mist-devel/plus_too/issues/3

I feel there's something at low level that it is missing, maybe just a timing issue?

Could you help me on determining how FX on lode runner works and what's expecting?

No reply?

the only discussion on this topic im aware of is in the other thread where you had mentioned the issue as well viewtopic.php?t=288&start=180

ericgus09 wrote: ↑Tue Jul 09, 2024 4:27 am

the only discussion on this topic im aware of is in the other thread where you had mentioned the issue as well viewtopic.php?t=288&start=180

yes, it was basically me trying to understand
but it got lost in a lot of other messages.

https://archive.org/details/Guide_to_th ... 1/mode/2up

jordi wrote: ↑Tue Jul 09, 2024 6:34 am

https://archive.org/details/Guide_to_th ... 1/mode/2up

Thank you! I've been looking for a while for a nice easy description of how the sound works in the old Macs. I believe the current core tries to output that byte as a D-A type value, not driving a PWM....

Off to load Quartus!

MrMartian wrote: ↑Thu Jul 18, 2024 11:40 pm

jordi wrote: ↑Tue Jul 09, 2024 6:34 am

https://archive.org/details/Guide_to_th ... 1/mode/2up

Thank you! I've been looking for a while for a nice easy description of how the sound works in the old Macs. I believe the current core tries to output that byte as a D-A type value, not driving a PWM....

Off to load Quartus!

no news are good news? hehehe, just joking

jordi wrote: ↑Wed Aug 14, 2024 2:34 pm

no news are good news? hehehe, just joking

Yeah sorry... I suddenly became the boss at work after the last one was let go suddenly.. :S

So, this was possibly easier to fix than I thought.. The fact that the signal was originally PWM gave me the clue though...

Please test and let me know!

Works as far as I can tell. The sound effects are audible now in Lode Runner.

MrMartian wrote: ↑Fri Aug 23, 2024 1:19 pm

So, this was possibly easier to fix than I thought.. The fact that the signal was originally PWM gave me the clue though...

Please test and let me know!

Wow! Can't test right now, but lot of thanks!!

MrMartian wrote: ↑Fri Aug 23, 2024 1:19 pm

So, this was possibly easier to fix than I thought.. The fact that the signal was originally PWM gave me the clue though...

Please test and let me know!

I am enjoying this fix immensely, at last the Macintosh audio seems to be complete! Many, many thanks for this!

vanfanel wrote: ↑Thu Aug 29, 2024 7:28 am

I am enjoying this fix immensely, at last the Macintosh audio seems to be complete! Many, many thanks for this!

Do you (or anyone else!) know of any other titles which have PWM sound which was previously inaudible (outside of Lode Runner)?

meauxdal wrote: ↑Thu Aug 29, 2024 2:42 pm

vanfanel wrote: ↑Thu Aug 29, 2024 7:28 am

I am enjoying this fix immensely, at last the Macintosh audio seems to be complete! Many, many thanks for this!

Do you (or anyone else!) know of any other titles which have PWM sound which was previously inaudible (outside of Lode Runner)?

I only know the missing Lode Runner sound effects with the older core, but I'd like to know about other games with previously missing audio.
Of the games I know, all of them seem to sound fine now.

Lode runner confirmed to have FX!! It improves a lot with it, and it is, for me, the best version of this game.

The end level tone musics are a bit saturated isn't it? They sound more low on the real computer.

jordi wrote: ↑Sun Sep 08, 2024 9:27 am

Lode runner confirmed to have FX!! It improves a lot with it, and it is, for me, the best version of this game.

The end level tone musics are a bit saturated isn't it? They sound more low on the real computer.

I want to try doing the audio in the exact digital PWM method as in the original hardware. I believe the way it's done now as analog makes the volume wonky...

That's why I said it's a quick fix now to get some sound, but needs to be redone..

MrMartian wrote: ↑Sun Sep 08, 2024 3:08 pm

jordi wrote: ↑Sun Sep 08, 2024 9:27 am

Lode runner confirmed to have FX!! It improves a lot with it, and it is, for me, the best version of this game.

The end level tone musics are a bit saturated isn't it? They sound more low on the real computer.

I want to try doing the audio in the exact digital PWM method as in the original hardware. I believe the way it's done now as analog makes the volume wonky...

That's why I said it's a quick fix now to get some sound, but needs to be redone..

Anyway your change is huge as it works

Lot of thanks