Just to make this more clear 5mm electret mic does work OK if i only want to hear people talking in a room but 5mm mic will not pick up people talking 2 blocks down the street with my 386 amp. The reason I use ear phones is because it blocks out all other sounds so I only hear what I am aiming at. If I aim 5mm electret mic at people talking 600 ft away I can not hear them but 10mm electret mic works good. With a little extra help using a cardboard cone 10mm electret mic makes people far away sound like they are only 3 ft away but 5mm electret mic will not do that. Sport stadium 1 mile away 5mm electret mic hears nothing, 10mm electret mic hears the crowd, 10mm with cardboard cone I hear lots of people talking. After dark I can slowly rotate cardboard cone in a 360 degree circle i can find people that are apparently setting in the back yard, on patio or deck relaxing & talking I have no clue where they are but they sound like they are only 3 ft away. We went camping for 3 days I aim 10mm electret mic with cone at people in a boat on other side of the lake I hear everything they say. I hear everyone in the camp ground there are lots of people setting round the camp fire talking 40 ft to 200 yards away. 2 women standing in front of restroom 400 ft away, 1 woman says, this bathroom has no toilet paper but the other restroom does. So I told my wife to take toilet paper restroom is out. This project is not only FUN but useful too.