MagicVOX  USB Headset Adaptor
Audio Interface Characteristics

• MagicVOX  NP350  USB Headset Adaptor
  http://www.i-bkm.com/english/product02.htm
  
  MagicVOX is a simple USB "Sound Card"
  with three connectors:

• Mic Input
• Headphone Output
• USB connector

• Microsoft Volume Control (mixer)

• Volume Control Slider Position Definition:

• Except as noted, all measurements were made at 1KHz and with Sliders set to Middle.

• Ref:  0.001V = 0 dBmV;  0.010V = 20 dBmV;  0.100V = 40 dBmV.

• All measurements were made on the Left Channel.  A spot check of the Right Channel showed virtually identical results.

  MICROPHONE Input -

• Mic Input Z:

• 960 ohms @ 20Hz
• 945 ohms @ 1KHz
• 311 ohms @ 20KHz

• Mic Bias:

• 1440 ohm to +3.1V

• Advanced Controls:

• None

• Mic Input Connector:

• 1/8 inch (3.5mm) stereo phone jack
• Tip contact is Mic Input w/ +3.1V bias
• Ring contact has no connection
• Sleeve contact is ground
• The Mic Input jack is marked:  

• Clipping:  Input Level for clipping vs. Microphone Slider Position

• Speaker Slider = Middle

• Levels:  Headphone Output Level vs. Microphone Slider Position

• 10mV (20dBmV) Mic input
• Speaker Slider = Middle

  HEADPHONE OUTPUT-

• Headphone Output Source Z:  25 ohms

• Clipping:  380mV (+ 51.6 dBmV) output

• Headphone Output Connector:

• 1/8 inch (3.5mm) stereo phone jack
• Tip contact is Left Headphone Output
• Ring contact is Right Headphone Output
• Sleeve contact is ground
• The Headphone Output jack is marked: 

• Levels:  Headphone Output vs. Speaker Slider Position

• 10mV (20dBmV) Mic input
• Mic Slider = Middle