How can I mesure loudness of the soundwave?

Somebody can help me 'measuring' the soundwave loudness : of higher than .. than ..
https://zimjs.com/docs.html?item=SoundWave
thanks to help
I tried the example
but the measurments are not readable
problem Imgur: The magic of the Internet

To just get loudness set the number of soundwaves to 1. Then that will give you an array with only one number that is between 0 and 1 usually. Anything closer to 1 is louder.