Canon MVX-150i (Optura 20) + DM 50
 
  The scope of this little test is to show the unwanted motor hiss found on the Canon MVX-150i (Canon Optura 20 for the US market).
The external microphone “Canon DM 50” eliminates much of this hiss, but still it seems that the AGC (Automatic Gain Control) amplifies all “silence” and generates a slightly whistling, when recording in almost silent areas.
Click on the thumbnails for a larger version of the frequency analyzes, and on the icon for the movie clips.
   
 
Movie clips
With original microphone
With DM 50 microphone
Comments
         

Recording performed outdoor.

Size: 3.7 mb, Type: wmv      
Recording performed indoor. Silent.
Size: 1.3 mb, Type: wmv      
Faint music. Please note that the camera (and microphone) is located in front of the mid-tone speaker, resulting in a little unbalanced tone picture.
Size: 2.5 mb, Type: wmv      
Loud music. Please note that the camera (and microphone) is located in front of the mid-tone speaker, resulting in a little unbalanced tone picture.
Size: 8.8 mb, Type: wmv      
 

The frequency analysis was performed with a Blackmann-Harris Fast Fourier Transform (FFT size 16384)