I have a sound board from an original Williams Defender (maybe the same used in Stargate, Joust?). I have a power supply to run it, a mechanical rotary switch to select the sound you want and a mechanical button to trigger it. I have been meaning to make a nice enclosure for it ... make a cool coffee table ornament.
Always loved those sounds. A friend made a 1-bit synthesizer and you could dial in sounds that occasionally suggested Defender. I assumed therefore the sounds were mathematically generated somehow.
I had tracked down the assembly for the board (probably used by MAME) but had not spent the time to reverse engineer the audio magic. Apparently someone has however.
Very cool. Mind blowing sounds when this game showed up at a nearby arcade — and its sill got it.
That "Game Start" sound is still so stunning. Just playing a bit with it, it looks like "echo" was the killer ingredient.