The first thing you will need is a microphone. There are 2 types of microphones, a Dynamic and a Condenser. A Dynamic mic can be plugged directly into your computer where as a Condenser will need a Preamp to carry what's known as phantom power, this is a voltage to power the mic into the computer.
Preamps come in various forms, it could be a mixer, a stand alone or other types, I want to keep this simple. Then you will need a program on your computer to record your audio.
I recommend Audacity, which is a program that you can download for free. You will also need another program called LAME to convert your . wav files into MP3s.
When you open the Audacity program you will see a bunch of round buttons on the top of your screen, just like you would see on any recording player. The red button is for record, the stop button is for stop, etc. Just below the record button is a drop down menu which gives you various settings ~ phone line, microphone, line in, etc. Set this on microphone when using a Dynamic mic. If you are using a Condenser mic, remember you will need phantom power, then you will need to set this to Line-In. Also on this drop-down menu is Mono Mix and Stereo Mix, this simply means that you want to record in stereo which is double wave file, or mono which is single wave file.
Next thing to do is adjust the settings. To adjust the settings go to the edit button on top of screen. On the drop down menu go to preferences to set your preferences here. You will see Audio, Quality, File Format, etc. Where it says Audio ~ set this on channel # 1 which is Mono, number 2 is Stereo. I recommend starting on number 1 and keep things simple. Next thing to do is set the default sample rate, I recommend setting this to 16-Bit and 44100 Hz. Be sure to keep your volume control on number five or around half way, to get a good signal.
To sum up, this is what you need
A Microphone, Dynamic or Condenser mic
Preamp or Mixer, if using a Condenser Mic, this is for phantom power.
A Stand to hold the Mic
Audacity Program, free to download
Lame Program, also free, to convert . wave files to MP3s
If you need my recommendations on where to purchase any audio equipment for recording, at a reasonable cost, please visit my website at celticseamus
For all your recording needs, visit my website at http://celticseamus.com/