2000 civic noises

I own a 2000 Honda civic and recently I started hearing a humming or whirring noise from under the hood area whenever im driving. I usually hear it when i hit around 35 mph and it gets louder the faster I go. I dont have to hit the acceleration to hear this noise either. I can also now hear a pinging sound when I hit the acceleration which I never heard before. This vehicle is an automatic. Any suggestions would be appreciated.

You sure that pinging isn't engine knock? Don't know what that humming would be though.

How would you explain the noise? Could you post a sound clip? Could it be one of the belts?