I do not know where in the world you are and what is your kind of music. I am in North America where the beat of most music is the bass so I would use a lowpass filter to feed a peak detector that feeds an LM3915 IC. I have a VU meter in my living room using an LM3915 LED driver IC. The IC lights the LEDs in the bar mode. So that it shows sound levels from the stereo, TV and conversations its input is an electret microphone, not a cable. it does not have a lowpass filter but it shows the beat if the music I listen to.
You showed a Monster Color Organ but it is not a color organ. All colors light at the same time. A color organ has each color light with the level of its band of frequencies.
If you use an LM3915 then it shows sound levels that are 3dB apart and each IC has 10 steps. Maybe you need two ICs that are cascaded to drive 20 LEDs? How many steps do you want? How many LEDs?