Before the participant arrives:

• Run check_audioLevels in MATLAB
• Select choice a) that the mic and headphones are working
• Listen in on participant's headphones and speak into experiment mic. Make sure you can hear your voice through the headphones and that the noise comes through cleanly in each ear.
• Press space to continue
• The next screen will tell you to make sure the headphones are plugged in to the correct output of the headphone amplifier *  
• Use the SPL meter to check the noise level
  • No max or min
  • A mode
  • Slow
  • Level 50-100 db
• Take the foam cover off of the SPL meter and place it inside the headphones
• The noise level should be about 60 db
• If it is not, adjust the appropriate headphone output knob on the headphone amplifier