I doubt there is much difference with both ecallers played on full volume. The sound is broken down more on the Shockwave since you are playing through two channels with two speakers on each channel, and two of them are Mylar tweeters. Either model is clear on high volume. To my ear, the CS-24C is more directional when you are using just the TOA it is built in, kind of like yelling loud with your mouth alone as compared to the same yelling with your hands cupped around your mouth to create sort of a megaphone effect. Of course if you play the CS-24C with an extra SP60, you get the direction and the volume. You can't go wrong with either model. They both have enough volume that I seldom use full volume. Don't forget that coyotes have superior hearing and they can hear easily what a human has trouble hearing at all.