If the noise follows rpm, you may have a problem.
Start by removing the belt to eliminate the compressor, The idler , the water pump and PS pump. If the noise is still present then check the torque converter bolts, disconnect the torque converter and slide it back, look for a cracked flex plate. If that checks out start the car with the converter disconnected. If it is still present and the noise is coming from the lower end of the engine you probably have rod knock.
Bryan