Beatdetector doesn't seem to work

Now I’m trying to make the shapes in my renderer react to sound. According to a tutorial, Beatdetector is the node for that.
Well, after several tries it seems that Beatdetector doesn’t hear the mp3 I play, or doesn’t care - it has its own rhythm. In fact, even if I don’t play any music, the sliders keep moving up and down.
What can I do so that it is sensitive to that music?

then you are probably listening to your microphone input. if you play the music on the same computer you need to select ‘stereo mix’ as input. if you dont have it, search the forum for it. this question was here many times…

yep, solved!