Get yourself a stethoscope or use a long screw driver and put it to your ear and touch the blade to different spots until it's the loudest. But, a stethoscope works better. A buddy of mine, years ago, had the earpiece from one of those antique candlestick phones and screwed a piece of threaded rod into it - wow! That thing worked great!
Awesome. I will do that for sure. Thanks for the tip