If you’re interested in listening to your bees then you’ll want to put a mic in your hive. I did just this following the lead of beehacker.com. The mic I used was a very simple un-powered electret mic. In order to use a mic like this you’ll need to plug it into something that’s wired to provide it with power. I use an iPhone with a specially-designed mic/headphone splitter. The splitter is 10x the cost of the mic but you only need one splitter for all of your hives.

Here are my photos from the build process.

Langstroth Microphone Frame