After a few recommendations here to try the Xcalibur Xr-50, I picked up a few and noticed that these things are friggin' loud! Excellent lures as well, caught a couple fish on 'em already.

I can hear the lure rattlin' from at least like 30 feet if it's quiet outside.

Which got me wondering, what kind of situations are better suited for louder vs. quieter baits??

I'm not sure. Supposedly after burning a rattln' crank the bass tend to get weary then you want to switch to a silent runner. I got a few of the New Bomber switchback cranks where you can turn on and off the rattle. I am waiting to see if it make a difference.

Another loud lipless crank is the Strike Kind 3/4oz diamond shad.

I definetely believe in clear water not having a rattle can be a big advantage especially in lakes that don't have a lot of cover. Though I would probably use a rattling lipless bait most of the time, I had a couple of days last fall where the Sebile Flatt Shad which doesn't rattle seemed to outperform my rattling lipless baits. The Lucky Craft RC series is available in a non rattling version, this is has definetely beeen my most productive shallow crank since it came out. Another readily available quiet crank is the original Rapala Shad Rap.

Loud rattles are definitely the way to go in stained water. Keep in mind that the rattles will get their attention. I found in clear water or when they are actively feeding rattles have less effect.

On highly pressured lakes I love to follow someone through an area throwing my traps that I have drilled and filled with glue to shut them up. You would not believe the difference it makes when the water is on the clear side.

There is an art to doing this so if you decide to try it let me know or you will destroy the action. The rattles must be positioned correctly for the lure to fall correctly.

I think it has more to do with the amount of fishing pressure than the water clarity. Bodies of water with a lot of pressure usually get hammered by crankbaits with rattles, and if you go there and use a crankbait without rattles you can do very well. I'm not saying you won't do well using a crank with rattles, but I think bass shy away from them after a certain point. The only time I think rattles are important to use are when the water is extremely muddy.