Power load and source questions (music controller with led strip load)
I saw youtube channel they used this power adapter with RGB strip. The question remain in my head, how did they used this kind of adapter if they are short with 12Watts?


The one on the youtube channel you saw probably worked because: 

1) there is quite a voltage drop on these strips, so the LEDs near the end use a bit less power; 

2) they only draw max current when fully on (Red, Green and Blue 100%), so any RGB color you use (Say purple: red and blue only) is going to draw less than 72W.


  2nd question: if watts in adapter does not care since my music controller support with 216w. Can I buy 2 RGB strip with 72w and use same time?


Your PSU has to supply more energy than your system draws. So you can't use a 60W PSU to supply 144W of LEDs, even if something in the middle can handle 216W.

Bottom line:

If I were you, I'd just buy a PSU that can handle more than what your controller can (say 12V 20A) and call it a day.