How to limit system processes cpu usage?
Thos system processes respond to other apps that run, so your first step would be to isolate and identify what programs you have that cause high background system load. 

It’s like racing a high performance car and seeing the tires are hot and fuel is being consumed rapidly - those all are the design intent when you press the accelerator to the floor. 

It might make more sense to start with your actual workload than try and hobble or disable logging and sound output. Sorry for a side answer, but those processes sit at idle for the vast majority of installations and likely would on your system if you restart and some troubleshooting should show exactly which of your apps trigger this usage pattern.