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gtaylormb / opl3_fpga

Reverse engineered SystemVerilog RTL version of the Yamaha OPL3 (YMF262) FM Synthesizer
GNU Lesser General Public License v3.0
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AO486 MiSTer - Secret of Monkey Island - SCUMM Bar Door Opening Sound is Incorrect #47

Closed hubby4 closed 3 months ago

hubby4 commented 3 months ago

This game supports Adlib only for FM, so I doubt this is a problem with the DSP.

You can hear how the SCUMM Bar door opening sounds on a real Adlib soundcard by going to the 4 min 26 sec mark in this video.

https://www.youtube.com/watch?v=ZTgfXSbGDBU&t=264s

gtaylormb commented 3 months ago

Any chance you can record a .dro file in dosbox/dosbox-x? That would really accelerate the debugging effort for me.

gtaylormb commented 3 months ago

One other thing--make sure you're using the latest unstable nightly build. There have been some fixes that have not yet made it into the latest stable release.

hubby4 commented 3 months ago

I used the latest 06-09-24 unstable build.

The DRO is attached.

monkey_000.zip

gtaylormb commented 3 months ago

Thanks for that. I'm able to replicate it--it does sound different to the real OPL3. The door opening sounds like 2 clicks on the OPL3. The second click seems to match (as well as the door closing sound), but the envelope on the first click for OPL3_FPGA seems to last about twice as long and kind of goes into an unmodulated sine wave the second half.

Retrowave OPL3 on DosBox-X: image

OPL3_FPGA on ao486_MiSTer: image

My guess is there's something up with the envelope and it should have released much sooner. I'll dig into it.

gtaylormb commented 3 months ago

@hubby4 thank you for this testcase! This wins the prize for hardest bug to find. Will be PRing into ao486.