If you want to play around with DIY microphones, try plugging a speaker (unpowered) into the microphone input on your sound card. I have had some speakers that made very good microphones. Some of them are very bass heavy - others can be quite good - and the diaphragm is so large on them they can be very sensative.

When I was in college (early '80s) lived in a 2nd floor apartment. I put my speakers in the windows facing out (one on the south wall, one on the east wall) and wired the leads into the mic inputs on my cassette deck. There were kids playing in the parking lot and a thunderstorm rolling in from the west.

Later on I put the speakers back in the windows facing in and played the tape. I had to look out the windows to be sure I was hearing the tape and not the kids playing. The distant thunder and passing traffic was all extremely accurate.