Professional dynamic microphones typically do not have enough output 
to properly drive a computer soundcard's Mic Input.  For best results, run 
the output of the microphone into either a microphone pre-amp, mic mixer or 
a suitable transformer/adapter before going into the soundcard.  

  Examples of commonly used dynamic vocal microphones:
      - Shure SM57, SM58, SM48
      - Radio Shack "Highball" mics
      - Samson S11 vocal mic
      - CAD SA2000 vocal mic
  
- A mixer or microphone pre-amp should be connected to the Line In 
  and not the Mic In. 

- A suitable low-impedance, balanced XLR-F to medium-impedance, unbalanced
  1/8" phone plug adapter (such as the Shure Bros. Problem Solver A96F Line 
  Matching Transformer) can be used between the microphone and the soundcard 
  Mic Input.  This particular adapter incorporates a "step-up" transformer 
  that boosts the level coming out of the microphone. 

- A mixer (although pricier) would be a better solution than a mic pre-amp 
  or transformer since a mixer will not only have built-in pre-amps and active
  impedance matching, but will also have tone controls for adjusting the tonal
  quality of both microphones and line level sources (such as CD players and 
  MIDI synthesizers).  The added flexibility is well worth the expense if you 
  are planning to do even semi-serious audio work. 


NOTE: 
You should always be very careful not to overload the soundcard's inputs with
excessive audio signal levels.  Severe overload can permanently damage any 
audio circuit, including those in a soundcard. 



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