Gen 3 Pokemon Inaccurate healing Sound Effect

[DarthPidgey]

As title says the sound effect for using a healing item like potions in a Gen 3 Pokemon game is inaccurate compared to real hardware, MiSTer audio was tested on both HDMI and IO board.
Sound effect comparison.zip

[Toryalai1]

What is your core version? Latest?

[DarthPidgey]

Yes the one released a few days ago, though it's always seemed to have the issue

[Toryalai1]

How did you record from GB?

[DarthPidgey]

Via the headphone out, recording software was audacity, but the sound is clearly different even if you were to listen by yourself no matter if it was headphone or speaker

[birdybro]

Sounds like the duty cycle is wrong. This sound effect happens on PSG channel 1.

[DarthPidgey]

the march 17th build didn't fix this

[DarthPidgey]

the mGBA emulator had the same sound glitch reported by me but was fixed today, any ideas on how to implement something similar? mgba-emu/mgba#3086

[RobertPeip]

Yes, looks possible to implement.
Can you please create a savestate before the sound effect in question?

Best would be for me: loading savestate -> press a -> sound happens.

Sorry, I'm very bad at hearing these differences, so i must be sure I'm researching the right thing.

[DarthPidgey]

savestates.zip
The pokemon pinball ruby & sapphire savestate is for the standard US version and should be the easiest to test. The others I used the leaked debug roms since they have an easily accessible soundtest allowing one to hear the sound effects with no music.

[RobertPeip]

TLDR: not fixed yet. Explanation below.

So the sound effect consists of 3 independent parts. Each part is starting with a frequency and then ramps it up using the sweep functionality.
You can see it in the screenshot(upper one is mister, lower is hw)

Interesting is the third sequence.
There is a new start marked with the red box , causing the frequency ramp to restart and therefore never reach the high frequency as it should.

I found a mistake in the code in that the freuency register is updated, even when only the lower 8 bit are written and even if the "Start" bit (initial) is not set, so I changed it.
However, it doesn't seem to have any effect.
I included the rbf and the changed source file in the zip here if anyone wants to debug further. I'm out of clues currently, sorry.
rbf_source.zip