MiSTer FPGA Forum

Galaxian is an awesome early arcade game which I regularly play and it's great on a CRT via the mister - however I noticed that the sound is not right, it seems to have a lower pulse frequency which is most noticeable when you clear a board and a new one starts - it almost seems like it's bugged until it gradually resumes a more natural tone after about 3 seconds.
Not sure if anyone is working on this core anymore but would be nice to iron out that issue, for what would then be (to me at least) an arcade-perfect experience

King & Balloon (which runs on Galaxian hardware) also has this issue.

Galaxian sound accuracy is apparently still an open question at this point, partly because it's not clear that all boards actually used the same component values. There's a lot of analog stuff in the sound hardware that might have been fudged with "close enough" resistors/capacitors in some production batches, not to mention potential issues associated with temperature and component aging.

https://mametesters.org/view.php?id=443

Very interesting reading!
I guess it's always a difficult (if not impossible) challenge to match analogue hardware since it varies with resistor/capacitor age and quality, also components reacting differently when warm etc.
Which is part of the charm of the old machines in a lot of ways.
Although in this particular case it seems as though the timing is off as well as the actual sound reproduction, which suggests that this isn't to do with idealised schematic implementation vs analogue circuitry.

From my experience, the background sound is much too loud. I think it's almost unplayable. Compare to recent Namco Classic Releases if the original board is not available. The sound also have glitches, but the wrong volume makes it really hard to play.

ExCyber wrote: ↑Sun Feb 07, 2021 6:28 pm Galaxian sound accuracy is apparently still an open question at this point, partly because it's not clear that all boards actually used the same component values. There's a lot of analog stuff in the sound hardware that might have been fudged with "close enough" resistors/capacitors in some production batches, not to mention potential issues associated with temperature and component aging.

https://mametesters.org/view.php?id=443

The background "rack" noise the enemies make (the drone sound) is completely wrong. Not an issue of being a little off, or differences in how boards sound. I've owned maybe a dozen different Galaxian boards, MAME sounds 100% better than Galaxian on MiSTer. The schematic is pretty simple, there are 3 different oscillators that feed into low pass filters, and then the result is summed. Looking at the Galaxian HDL, it looks like a sine waveform approximation?

shertz wrote: ↑Sun Feb 07, 2021 3:56 pm King & Balloon (which runs on Galaxian hardware) also has this issue.

And UniWarS, it also uses the same circuitry for the background sound.