Yours is Oem? It's not going to damage anything if that's why your asking. Just another quirk, of which this car has plenty.

 

The sheet metal heat shield between the exhaust header and battery can "ring." It's supported only at the bottom side. Resonates from engine vibration. Usually reported in lower rev range. Fades at higher rpm.

To test you can take it off. Then put it back.

 

Do you have the lid on tour intake box?

 

Make sure airbox lid is on correctly. Specifically around the rubber intake arm portion.

 

I think the sound is actually an injector and is totally normal. I will start calling it "Honda injector ring" because I have driven lots of Hondas with it.