Background "wave" effect in SH3 ports

[EOJ]

I've noticed this in both Deathsmiles and Futari. It's more apparent on a SD monitor, but you can still see it on an HD one. Basically, the background has a translucent "wave" effect that goes through it as the screen scrolls across. Sometimes it seems to slightly distort or bend. Is there something about the SH3 hardware that is causing this? You don't see it, for example, in the DDPDOJBLEX port on the 360, but that's ported from different arcade hardware.

Anyone have a clue?

[SuperPang]

Not a grounding issue with your supergun?

[cstarflare]

He's referring to ports of SH3 games, not SH3 games themselves.

I've never noticed them, but I don't really pay attention to that kind of thing. Next time I throw deathsmiles in I'll give it a look.

[EOJ]

Yeah, when I play the PCBs on my supergun, they are crystal clear, without this effect.

I should add you can also see this on the superplay DVDs of the PCBs. For example, check out the Deathsmiles superplay DVD. Maybe it has something to do with the interlaced signal?

[SuperPang]

Ahh, I see. Sounds lilke the flicker of an interlaced image. Shouldn't be there in the HD modes at least though.

[EOJ]

It's not a flicker. It's in the HD modes too. And like I said, non-SH3 ports don't have it (i.e. DDPDOJBLEX). Quite bizarre.

[Dave_K.]

I've noticed this wave too, particularly in the Futari title/intro screens on my tri-sync cabinet (640x480@60hz).  To me it looks very similar to what I see in mame when the refresh rate of the game isn't sync'd exactly to the refresh rate of the display.  So an artifact of their emulation is my guess.