Recording Studio Equipment:

Audio Interface

What does an Audio Interface do?

In the most basic sense, an audio interface upgrades the sound output of your computer. Most computer soundcards + outputs (including the ones that come installed in Macs) are not intended for the higher resolution output associated with music production and DJing.

In addition, an audio interface works in preparing sound that you bring into your computer. If you are recording / sampling into your computer, an interface ensures you'll record quality, high resolution sound.

Microphones:

Microphones are all devices to convert sound pressure levels into an electrical current. Dynamic mics’ diaphragms move a coil of wire near a magnet, much like a small speaker in reverse. (In fact, if you wire a speaker, or a pair of headphones, into a microphone input, either will perform as a microphone–not a very good one, but either will act as a transducer from sound waves to electrical impulses.) Condenser mics use “phantom power” to create a charge differential between a suspended diaphragm and a fixed backplate. In either design, as the diaphragm is moved by sound pressure changes, the microphone translates that movement into electrical impulses.

Headphones 

Ideally, studio headphones are:

• Designed with more or less flat frequency response with no bass boost or any undue prominence in other frequency regions. This is to make sure that any unpleasantness heard is due to mistakes in the miking/mixes and not in interaction with the headphones. 
• Have decent passive sound isolation. Studios are noisy places. You can't effectively monitor a recording in headphones that do not provide adequate isolation.
• Comfortable, so that one could wear them for hours on end.
• Sturdily built. Professional equipment is not cherished like home hi-fi. It's used and abused and thrown about and stepped and sat on.
• Inexpensive, so that there is no drama when the headphones finally give in to abuse and have to be replaced.
• Ugly, so that no musician would be tempted to "accidentally" mislay a pair into his/her gear bag.
  

Laptop

Garage Band