The default configuration settings for Term-LAB will "mute" SPL readings below 120 dB. If you want to display values below 120 dB, you will need to change these default settings.
Select “Tools / Hardware Configuration” from the Term-LAB pull-down menu.
Select the “Input Devices” tab.
Click on “Edit” next to Sensor 1.
Change the “Min SPL” value to 80 and then click “Save”. (This is the "Mute Threshold". Any SPL measurement that is LOWER than this threshold value will sho up as "000.0" on the Term-LAB display.)
Repeat this process for Sensor 2.
It is important to note that the software will not allow changes to the input devices if a contest is in process. If you encounter this restriction, start a “New Contest” for each judging mode that has competitors entered present.
Please note that Term-LAB was designed to measure high sound pressure levels. SPL measurements below 110 dB are not recommended. It is normal to see a reading of 95-115 dB WITHOUT any sound present. This is due to the electrical noise floor of the system. To improve the Signal to Noise ratio of measurements below 160 dB, please use the following procedure.
Select "Tools / Display Options" from the Term-LAB pull-down menu.
Change the "Top" slider to a value of 160 dB or less.