Genesis Plus GX, Where is the Audio Lowpass Filter?


What if I’m using GPGX to play Game Gear and Master System games, should I disable the lowpass filter?


YM2612, Stereo, Low-pass, 55.


If you used to play with a Master System Converter (or Everdrive) on the Genesis, then keep it On.
The hardware Master System just like NES did NOT have a lowpass filter, so turn it Off for authenticity.


DAC quantization should also be ON right? Or is that setting MAME only?


DAC quantization is for Mame core only.
All the Nuked cores have all the proper emulation of the electronics already.


So with the most recent core update, there are now 3 different nuked soundcores (ym2612; asic ym3438; discrete ym3438) Which one is the one to go for most authentic model 1 sound?


Three posts above I answered just that…


Thanks. So what are the two others for then?


Discrete YM2612 appeared on all Model 1 except the badly distorted VA7.

ASIC YM3438 was integrated into the main chip on the majority of Model 2 except VA2 and VA2.3 which had Discrete YM2612 like Model 1.

YM3438 has better DACs and sounds cleaner with less ‘ladder effect’ (google it) distortion and noise than YM2612.
BUT, some games actually use the YM2612 ‘ladder effect’ noise to their advantage therefor sound more correct on the 2612 than on the 3438.

Discrete YM3438 never appeared in any Genesis console but it sounds similar to the ASIC YM3438 and can be installed in a Model1.

Mame core is the most pristine sounding with no emulation of the ladder effect distortion, and no DAC Quantization (if Off), it is a pure FM synthesizer.
This option is actually what Sega engineers would have preferred but had to live with the distorted and noisy real hardware. :smile:

You can clearly hear the difference in Contra: Hard Corpse, in the Music Test menu play “Konami Music”, it is clearly audible on the polyphony of bells.


Hellfire is the best example of sound difference. Jump straight to 5:28 and 12:32 to compare.

UPD: I wonder if there any game that actually leverage YM3438 chip? Maybe some kind of list of such games exists?


Holy shit, I’ve seriously never been able to tell the difference. Those timestamps were way useful.

If nothing else the speed of how the sound is handled on the Model 2 sounds horrendous compared to the Model 1 here.


Oh man, wish I had found this thread earlier… nice development on the YM2612 btw!

I’ll have to try it out. Right now RYMCast has set the benchmark as far as accuracy goes, I’ll see how this new core fares.


Can the setting for Model 1 sound be Mono instead of Stereo?


So did the Nuked core get removed or is it default now? I have the latest core and no audio core options are available.


It’s there. In quick menu > options, go down to Mega Drive / Genesis FM and scroll until you see ‘nuked (ym2612)’


I don’t have it. Retroarch 1.7.6 Win 7 x64, core version 1.7.4 997360b.

There is Master System FM but nothing else labelled anything like Mega Drive / Genesis FM.


Looks like your core might be out of date. What platform?


I listed my platform and all version numbers above. I just used Core Updater today and this is the core I got. What version number core are you on?


You can see my version, f5eed51, in the image. It’s the most recent version, last built on Feb. 2, it looks like.

Can you try deleting the core manually from the cores folder and re-download?


I deleted the core and redownloaded from the page you linked and I still get the same thing. What the hell?


Are you loading from a playlist? If so, is it possible you have an old copy of the core lying around somewhere that the playlist is linked to?