Suggestion: Let the car sit overnight. Remove the primary belt. Start the car. Are the sounds the same? I hear two different sounds. One sounds like the injectors. The other I can't tell. With over 100k-miles the injector sound is to be expected. DO NOT let the engine run for more than a few minutes without the belt, maybe 5-10 minutes. There is no coolant circulating without the belt. If the "knock" you say you hear is gone with the belt off this helps narrow down the source of the sound.