Knocking from 1500-2000rpm 3.4 V6

I was listening to my car the other day and i heard the engine knocking around 1500-2000 rpm in gear. I ran oil tests at blackstone that said the oil is completely free of metals and the filter looked good when i changed the oil(no shavings). you cant really hear the knocking when youre driving but if you hold the break down and rev it you can hear it. I tried to check it out with a stethoscope and managed to listen to it. The knocking didn't sound like metal on metal and was a softer. Part of me thinks that it might be normal engine noise but i am not sure. I've got tons of holes in my exhaust but it doesn't seem like a leak. When i try to recreate it in neutral/park the noise is still there, just not as much exhaust noise and you can't hear it without a stethoscope. What do yalls engines sound like at 1500-2000? and what are some tips to make sure that my engine isn't knocking.

 

wrong forum guys sorry