Measure using loudspeaker as source

This method is default and should give the most reliable results and is according to ISO 345.

Open Measurement->Settings... and make sure it looks like below if you are measuring with 1 microphone.

If the maximum reverberation time in the room you are measuring is longer than 1.5 seconds, you should type in this new number instead of 1.5 shown in the figure above. To estimate the maximum reverberation time you can clap your hands and listen to the decay.