check your audio setting on the clarion. It is easier to destroy speakers with too little power then to much since the square wave kills faster. Mostly.. mostly having more power helps with THD and gives you more head room.. ie playing louder but clearer. I would pull the speakers out and try hooking them up to another audio sources and see if they still sound bad. Also try different speakers using the same radio. You may have a bad head unit with a blown mosfet or something. Don’t forget to check your impedance also. Are the 45 watt speakers factory?
If all else fails verify your grounds. Ground loops are a common problem and can amplify with more volume. Some cars did use the chaise as a common ground for their speakers.. A big pain in the ars.