AST RESEARCH, INC.       INFORMATIONAL BULLETIN # 0035       02/04/97 
 
 
 
TITLE:  Feedback on Multimedia Mobile Systems
 
 
SUMMARY 
 
   It may be possible to produce feedback from an Ascentia 
   multimedia system's internal speakers or from external speakers 
   connected to the system. 
   
   Feedback is caused by sound coming from the speakers which is 
   picked up by the microphone. The sound is amplified and 
   reproduced by the speakers. This creates a loop of sound being 
   picked up and amplified creating the high pitched sound. This 
   condition may be aggravated 
   on mobile systems due to the close proximity of the microphone 
   and the speakers. 
   
   This issue may be reproduced on desktop computers by holding the 
   microphone close to the speakers.
   
   This issue affects all mobile systems.    
 
 
NOTES 
 
   This condition is easily remedied by decreasing the microphone 
   (mic) gain on the computer. 
   
   For example, to decrease mic gain on an Ascentia P under DOS, 
   perform the following steps:
   
   1. Enter the following command and then press the <Enter> 
      key:
   
        cd\vibra16 
   
   2. Enter the following command and then press the <Enter> 
      key:
   
        mixerset 
   
   3. Arrow-down to the mic slider control (the indicator 
      will blink) and use the left arrow key to decrease the 
      mic level.
   
   4. Press the [Tab] key until "Save" is blinking and press
      the [Enter] key. This will save the DOS mixer 
      settings.
   
   5. Press the [Esc] key to exit the mixer.
   
   To adjust mixer settings in Windows 3.x, use the Creative Mixer.
   
   To adjust mixer settings in Windows 95, use the built-in mixer. 
   
   Please consult your documentation for instructions on adjusting 
   the mixer in your system.    
 
 
TAN TPR 2616PS 
 
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