MiSTer FPGA Forum

Hi there,

There's that game on the Atari 5200 that I absolutely love: Gremlins.
It has fantastic music by the late Brad Fuller, who was the best arcade music composer ever (for my taste of golden-age arcade gaming music).

However, the music on the Atari 5200 core sounds SO massively saturated to me! Do you guys know if that was the case on original 5200 hardware? I don't have any Atari 5200 hardware around to compare...

You could compare that with the famous Atari800 Emulator which is also havin' a 5200 emulation.

Good idea, RealLarry!
I just installed latest stable Atari800 on my Debian system, and in fact, the game sounds equally distorted and saturated...
I guess that's how the game was! Back in the day I didn't have such a delicate ear, I guess? Most of people seems to lose ear capability with age, I seem to be wining it somehow.

Maybe the emulated versions are lacking a low-pass filter on the audio output.

You could also try to find and use another rom dump. Looks like there were several prototypes, maybe you are using one... Send me the checksum of your rom and I'm compare it with my collection(s).

RealLarry wrote: ↑Tue Nov 12, 2024 11:44 am

You could also try to find and use another rom dump. Looks like there were several prototypes, maybe you are using one... Send me the checksum of your rom and I'm compare it with my collection(s).

md5sum Gremlins\ \(USA\).a52 
dc271e475b4766e80151f1da5b764e52  Gremlins (USA).a52

This is the No-intro USA version, so I would say it's pretty much "the real deal".

Oh, an unknown one! My are

fe8ceab71fba988c2cf123936c0d83d1 Gremlins (1984) (b1)-good5200.a52 (also tosec)
3fbcf758e25783ace70aa925891b6a42 Gremlins (1984) (b2)-good5200.a52
c7e257a853902c6044ca067be3e7761f Gremlins (1984)-good5200.a52 (also nointro)

"b2" has garbage on the start screen, but all three are having saturated audio.
@LamerDeluxe seems to be correct in his assumption...

Does the 5200 have a low-pass filter at all? I mean, the real hardware.

Hm..just tried Gremlins on the Altirra emulator (Linux/WINE) and it plays the sound fine there.

...and if I disable /Sound Settings/High Fidelity POKEY in Atari800 it also sounds fine then!

vanfanel wrote: ↑Tue Nov 12, 2024 12:02 pm

Does the 5200 have a low-pass filter at all? I mean, the real hardware.

No, but your TV at the time would effectively have a filter, since those speakers would not reproduce the very high or low frequencies.

It’s a pet peeve of mine when people show arcade emulation or any 8-bit sound chip without a low-pass filter in videos. It did not sound like that, not in the arcade, not at home.

There’s a reason I default all arcade cores (and most of the 8-bit console cores) to 2kHz LPF in MiSTer.ini

I guess the RF connection to the TV would also act as a very strong low-pass filter.

limi wrote: ↑Tue Nov 12, 2024 2:17 pm

There’s a reason I default all arcade cores (and most of the 8-bit console cores) to 2kHz LPF in MiSTer.ini

How is that done on the .ini, please? What's the setting I must set? I use HDMI for video and audio.

I use the following settings (you can apply this to any core in the same way, this is for arcade):

[arcade]
[arcade-vertical]
afilter_default = Arcade LPF 2khz 1st + 20khz 2nd

There’s a bunch of different audio filters available, so definitely try them out in the OSD if you want to hear the difference they make, and then you can set it as the default once you find one that sounds like you want.

limi wrote: ↑Tue Nov 12, 2024 3:41 pm

I use the following settings (you can apply this to any core in the same way, this is for arcade):

Code: Select all

[arcade]
[arcade-vertical]
afilter_default = Arcade LPF 2khz 1st + 20khz 2nd

There’s a bunch of different audio filters available, so definitely try them out in the OSD if you want to hear the difference they make, and then you can set it as the default once you find one that sounds like you want.

I see, it seems to be like the presets in "Video Processing", which I use extensively. Many thanks!