I have an 06 Hybrid that pings at a steady state. During acceleration you can't hear it, and if you ad just a little throttle during cruise it is reduced. Kind of opposite of normal pinging which is worse on acceleration. I did notice more carbon build up than other Honda's I have owned (6) when doing the valve adjustment. Will excess carbon build up cause the pinging? Haven't went after the knock sensor yet as no codes are present or pending. Premium fuel does help somewhat.

 

If you have been feeding your car a steady diet of low grade fuels you might have carbon build up, or the timing could be off.

Have you checked your exhaust system for loose parts that can vibrate and sound like a pinging noise?

The cover on the cat is a good place to start for the noise.

 

Responding to the bolded portion.

In general, yes. They create "hot spots" (which can encourage pinging) as well as raise the compression ratio slightly (which can also encourage it).

Other possible causes could include:
lean AF ratio
incorrectly gapped plugs
excessively advanced timing
excessive engine temp
excessive intake temp