
The sound they make is different to anything I've ever heard...a bit more like something they might have in Europe or something. It sounds like WAHWOW, WAHWOW, WAHWOW, WAHWOW. The only thing I can compare it to is the constant background sound in this music clip (noticable after 7 seconds in): http://www.youtube.com/watch?v=ekPaYGVLifY. Not exactly like that, slightly faster paced, but it's the only thing I can compare it to. The strobe blinks off and on while it sounds (on at every "wah").
If anyone lives in the Grand Rapids area, go take a look. There's five of them in the store. Three emergency exits have them mounted above the doors (the one I saw going off last week was in health and beauty care) and two that are seemingly randomly placed in grocery. The store was built in the 70's, I believe, so these could be very old alarms. I'm really curious as to what they are or if anyone knows of an alarm that sounds like what I'm describing. When it went off when I was about five years old it scared me so bad I've actually had recurring dreams about it ever since. But they're actually not all that loud. I've seen ONE of these strobes at the Cascade Meijer, and for some reason that one is in frozen foods.
On a side note, the 54th st/Clyde park Meijer also has an amber colored strobe up near guest service. It seems like this went off a lot when I was a kid, but I have no idea what it's for.