I don't quite understand why some things are overdone on my eyes on this expressions like the frequencybin.
Anyway I was curious too about how to achieve this effect and I modified it to have that wave look I think you were looking for, as it is the steps are too big and it doesn't look that pleasant.
Capx:
https://www.dropbox.com/s/3bleznaixtlvlot/Audio%20Spectrum%20Effect.capx?dl=0
Also I find quite annoying that fadeout end when the bar moves just a little big in the end, I would like to make it sharper, I wonder if changing the size instead of moving the whole object makes it better, I wonder too why they made it so it moves the whole thing instead of resizing must be a performance choice. On a second thought it may be my screen not been able to refresh fast enough altho construct is capped at 60fps, because I cant get to screenshot the fade effect.
Edit:
Upon further inspection what I did has too little variation between frequencies, so if you want to make something as selective as in the video you may have that when a low sound happen it blow on one corner and the others go down you need to find the start and end frequency just like the guy on the video said it's different for every song it you want it to look as smooth as in the video, otherwise you can use have been done before, which is just a display of all the frequencies divided between the bars.