MAMEWorld Forums - EmuChat - Re: Space Invaders emulation

Well written informative report since it provides detailed explanations.

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https://mametesters.org/view.php?id=6590

When discrete sound emulation was added to invaders in 0.114u2, it was based on a Midway board. However, Taito boards had different sound effects (most notably the sound of destroying an invader).

Video footage of various bootlegs/clone PCBs found online (e.g., Cosmic Monsters, Space War) shows that they are also derived from the Taito sounds; even when they vary from official Taito boards and from each other, they sound like variations of the Taito sounds and not the Midway ones.
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>it would appear that when Midway licensed the game, they built their own discrete sound
>components instead of reproducing Taito’s. When MAME added discrete sound emulation for
>Space Invaders, it sounds to have been based on a Midway board. Every version that uses
>the discrete emulation instead of the old samples plays the Midway sounds (which
>themselves don’t sound exactly like real Midway machines, either).

>When the game used sound samples in MAME, it used the Taito sounds, but only one sample
>of each sound, which is also inaccurate. As you pointed out, the sounds are not
>absolutely identical every time. I have no idea how the sound actually works, but the
>invader death sound (probably both Taito’s and Midway’s, but most obviously Taito’s)
>seems to start/end in different places each time you hear it.

*for any folks that weren't following MAME emulation in 2007*

Back in 2007, Zsolt Vasvari [former dev] and Derrick Renaud were working together when the Midway 8080 games were separated to their own new file of mw8080.cpp from the 8080bw.cpp source file.

Zsolt was moving around the Midway 8080 games while Derrick Renaud was doing the discrete analog audio sound effects and adding those to various Midway 8080 hardware games. Derrick was using already online scanned pdf files of Midway logic schematics from those large size foldout schematics sheets that would be supplied with shipped Midway 8080 hardware games. Other schematics sheets such as Amazing Maze and others were actually mailed to Derrick (resides in Ontario region of Canada) to do discrete audio emulation.

Both Zsolt and Derrick did a fair amount of quality work with the Midway 8080 update at the time. A lot of the Midway games did not have any audio emulated until about 2007. Still a lot more of Midway discrete/analog audio needing to be done, but who knows when.

>The solution would be for someone to write additional code to emulate the discrete sound
>of a Taito board, and implement that emulation in all non-Midway versions in place of
>what is there now.

Yep. Good luck with someone having to determine the components of the Japanese region hardware to seeing how to do analog audio emulation from the logic schematics in case the person can't get access to the actual components for testing in this day and age.