snake noises?

[macandchz]

could someone please explain what noises besides ssss! a snake makes? another forum has been talking about a snake with a R.I. and the noises such as popping, whistling, etc. They mentioned that scales can make noise, bedding can cause popping or clicking. what are these noises and does a healthy snake make them? should i be routinely checking for these? should i be routinely opening his mouth and checking for bubbles?